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Subtypes

2

Neurotoxic envenomation (Buthidae)

The form responsible for essentially all scorpion mortality worldwide. Buthid venom is neurotropic and not cytotoxic: it produces no local tissue reaction to speak of, and the illness is entirely a consequence of sodium-channel-driven autonomic discharge. All of the pathophysiology in this entry from the sodium-channel node onward describes this subtype.

Show evidence (1 reference)

PMID:9679690 SUPPORT Human Clinical

"Different species of the Buthidae family, which were responsible for the remaining 90% of scorpion stings, have a neurotropic and noncytotoxic venom and, as a result, induce no cutaneous reaction."

States the defining property of this subtype and, by contrast, of the other one - in a series large enough to give the proportions.

Cytotoxic envenomation (Hemiscorpius lepturus)

A mechanistically separate disease that happens to be caused by a scorpion. Hemiscorpius lepturus venom is cytolytic rather than neurotoxic, and the sting is characteristically not painful at the time. What follows is delayed dermonecrosis, intravascular haemolysis, acquired ADAMTS13 deficiency with autoantibody, and thrombotic microangiopathy with acute kidney injury. None of the autonomic storm chain applies.

Show evidence (1 reference)

PMID:9679690 SUPPORT Human Clinical

"HL venom is cytotoxic, and HL is the only scorpion whose venom induces a toxic reaction."

Establishes the separate venom class this subtype turns on.

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Mechanistic Hypotheses

2

Catecholamine storm drives the fatal cardiac dysfunction

adrenergic_catecholamine_storm CANONICAL

Evidence balance 2 support

The long-standing account. Sodium-channel toxins drive sympathetic terminals and the adrenal medulla to release catecholamines in bulk; the resulting adrenergic myocarditis, raised afterload and myocardial ischaemia produce left ventricular failure and pulmonary oedema. This is the model that motivates prazosin, and the model under which the alpha-1 blocker's clinical benefit is read as mechanistic confirmation.

Pathograph links

Autonomic Neurotransmitter Storm -> Catecholamine-Mediated Myocardial Injury DIRECT The adrenergic arm, and the one the canonical account holds responsible.

Catecholamine-Mediated Myocardial Injury -> Cardiac Dysfunction and Pulmonary Edema DIRECT

Show evidence (2 references)

PMID:15687982 SUPPORT REVIEW SYNTHESIS Human Clinical

"Adrenergic myocarditis, toxic myocarditis and myocardial ischemia are the 3 mechanisms that explain the cardiac dysfunction."

The canonical account stated as three adrenergic and ischaemic routes, with no cholinergic arm among them.

PMID:37018229 SUPPORT Human Clinical

"The management typically included inotropes (especially dobutamine), prazosin, diuretics, nitroglycerine and digoxin, when indicated."

The practice this hypothesis generates - alpha-1 blockade and inotropic support - pooled across 703 human cases.

An IL-1R/PGE2/acetylcholine neuro-immune axis drives it instead

il1r_pge2_cholinergic_axis EMERGING

Evidence balance 2 support

A mouse account that puts the fatal arm on the other side of the autonomic nervous system. Venom recognition drives cardiac IL-1 receptor signalling and prostaglandin E2 production; PGE2 acting at EP2/EP4 receptors then drives excessive vagal acetylcholine release, and it is that cholinergic signal, not the adrenergic one, which produces the heart failure. Four independent interventions - IL-1R knockout, high-dose dexamethasone, atropine, and vagotomy - each abolish mortality in envenomed mice, and the authors note the pathway is untouched by antivenom. Recorded as EMERGING rather than ALTERNATIVE because nothing in it has been tested in humans.

Pathograph links

Venom-Triggered Cardiac IL-1R Signaling and PGE2 Production -> Excessive Vagal Acetylcholine Release at the Heart DIRECT

Excessive Vagal Acetylcholine Release at the Heart -> Cardiac Dysfunction and Pulmonary Edema DIRECT The claim that distinguishes this hypothesis from the canonical one: the heart failure is cholinergic in origin.

Show evidence (2 references)

PMID:33116136 SUPPORT Model Organism

"cardiac dysfunction and fatal outcomes caused by lethal scorpion envenomation in mice are mediated by a neuro-immune interaction linking IL-1 receptor signaling, prostaglandin E2, and acetylcholine release"

The hypothesis in the authors' own words, with the species it was demonstrated in stated in the same sentence.

PMID:33116136 SUPPORT Model Organism

"we introduce a novel pathway that is targeted by dexamethasone, but not by anti-scorpion venom serum"

What makes the two hypotheses prescribe differently rather than being two descriptions of one thing.

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Discussions and Knowledge Gaps

2

Which arm of the autonomic storm actually produces the fatal cardiac dysfunction in human scorpion envenomation - the adrenergic one, or the IL-1R/PGE2-driven cholinergic one?

KNOWLEDGE GAP which_autonomic_arm_kills

Attached to

pathophysiology#Catecholamine-Mediated Myocardial Injury pathophysiology#Excessive Vagal Acetylcholine Release at the Heart mechanistic_hypotheses#adrenergic_catecholamine_storm mechanistic_hypotheses#il1r_pge2_cholinergic_axis

Both arms are real and both are measurable in the same envenomed animal - adrenaline and acetylcholine rise together. The question is which one the heart failure follows from, and the two answers point at opposite drugs. The canonical account is adrenergic, and prazosin's clinical benefit is usually read as supporting it. The mouse account is cholinergic, and it is supported by something stronger than a correlation: IL-1R knockout, dexamethasone, atropine and vagotomy each abolish mortality, which is four interventions at three different points of one pathway. What makes this more than an academic dispute is that the two accounts prescribe differently. Under the canonical model an alpha-1 blocker treats the lethal mechanism; under the emerging one it treats a real but non-lethal arm while the fatal pathway runs untouched - including, the authors note, untouched by antivenom. A trial of early dexamethasone or of atropine in human envenomation would separate them; none has been done. Note also that the evidence is asymmetric in kind, not just in strength. The adrenergic account rests on human clinical observation and on a therapeutic response; the cholinergic one rests on mechanistic intervention in mice. Neither body of evidence is of the type that would refute the other.

Show evidence (2 references)

PMID:15687982 SUPPORT REVIEW SYNTHESIS Human Clinical

"Adrenergic myocarditis, toxic myocarditis and myocardial ischemia are the 3 mechanisms that explain the cardiac dysfunction."

The canonical side of the disagreement, in a human clinical review.

PMID:33116136 SUPPORT Model Organism

"IL-1R deficiency, the treatment with a high dose of dexamethasone or blockage of parasympathetic signaling using atropine or vagotomy, abolished heart failure and mortality of envenomed mice."

The other side, and the reason it cannot be dismissed as correlation - four interventions on one pathway, each abolishing the outcome.

Does the IL-1R/PGE2/acetylcholine axis shown in envenomed mice operate in human scorpion envenomation?

HUMAN MODEL MISMATCH il1r_axis_is_mouse_only

Attached to

pathophysiology#Venom-Triggered Cardiac IL-1R Signaling and PGE2 Production pathophysiology#Excessive Vagal Acetylcholine Release at the Heart treatments#Early dexamethasone

Every step of this pathway - the inflammasome-dependent IL-1 beta, the sustained PGE2, the EP2/EP4-mediated acetylcholine release, and the rescue by dexamethasone, atropine or vagotomy - was established in mice given Tityus serrulatus venom intraperitoneally at a defined lethal dose. That is a well-controlled demonstration and it is not a human result. Three specific reasons to hold the translation open. The route and dose are not those of a sting: an intraperitoneal bolus at 180 micrograms per kilogram is not a subcutaneous envenomation of uncertain quantity. The species is one whose venom has been studied in Brazil, while most of the world's scorpion mortality is caused by other genera on other continents. And the human evidence that does exist for an inflammatory contribution is correlational - circulating IL-1 beta separates patients with and without cardiac abnormality - which is consistent with the pathway being causal, with it being a marker of severity, and with both. Note that the same study found the pancreatic association statistically insignificant, so the human data support the cardiac half of the mouse account and not the pancreatic half, even though the paper's title names both. This is filed as a model mismatch rather than a knowledge gap because the evidence is not absent: it exists, it is good, and what is open is whether it transfers. Resolving it needs a human study, and the obvious one - early dexamethasone against standard care - is also the one the mouse work proposes.

Show evidence (3 references)

PMID:33116136 SUPPORT Model Organism

"PGE2 signaling via EP2/4 receptors mediates excessive ACh release, which in turn causes the heart failure of envenomed mice"

The pathway whose translation is in question, stated with its species restriction in the same clause.

PMID:41327440 SUPPORT INDIRECT BACKGROUND Model Organism

"Recent experimental studies on animals were held to prove the correlation between interleukin 1 β (IL-1β), lipid peroxidation and nitric oxide (NO) production in the development of cardiac and pancreatic abnormalities after scorpion venom exposure."

The one human study on this axis opens by stating that the causal work was done in animals, which is the mismatch this discussion is about. Graded MODEL_ORGANISM because `evidence_source` classifies the evidence the quoted text describes, and this sentence describes animal studies - the same rule the entry applies in the other direction elsewhere.

PMID:41327440 SUPPORT INDIRECT Human Clinical

"Regarding cardiac abnormality, there were significant statistical differences with both levels of IL-1β and MDA."

The study's own human result, and the whole of it: IL-1 beta separates patients with and without cardiac abnormality. INDIRECT because an association between a cytokine level and a complication does not establish the causal pathway the mouse work describes.

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Pathophysiology

10

Scorpion Venom Neurotoxin Binding to Voltage-Gated Sodium Channels

Buthid venom carries small peptide neurotoxins that bind the voltage-sensing domains of voltage-gated sodium channels. The alpha-toxins are the structurally resolved case: AaH2 from Androctonus australis wedges into voltage-sensing domain IV and traps it in a deactivated state, so the S4 helix cannot make the translation that normally unlatches the fast inactivation gate. The modifier on the channel activity is `GAIN_OF_FUNCTION` rather than `INCREASED` deliberately: the claim is not that sodium current is quantitatively larger but that the channel has been taken outside its own regulatory constraint, since the gate that terminates its opening no longer operates. There is no host variant anywhere in this, so there is nothing for `functional_impact_category` to describe - the gain of function is imposed on a normal channel by a bound peptide.

voltage-gated sodium channel activity, with fast inactivation disabled GO:0005248 ⇑ GAIN OF FUNCTION

Downstream

Failure of Sodium Channel Fast Inactivation and Repetitive Firing Trapping VSD4 in its deactivated state is the same event as preventing fast inactivation - the structure shows the mechanical linkage directly.

Local paresthesia at bite site The immediate local pain is attributed to the venom arriving in the tissue, and it is the earliest sign of envenomation. Marked INDIRECT_UNKNOWN_INTERMEDIATES rather than DIRECT on purpose: the source links the pain to venom penetration without naming the receptor or the afferent population it acts on, so the steps between this node and the symptom are not established here. The obvious candidate - the same sodium-channel action on peripheral nociceptors - is not what the cited sentence says.

Show evidence (1 reference)

PMID:30733386 SUPPORT In Vitro

"AaH2 wedges into voltage-sensing domain IV (VSD4) to impede fast activation by trapping a deactivated state"

The binding event this node records, at 3.5-angstrom resolution in a toxin-channel complex.

Failure of Sodium Channel Fast Inactivation and Repetitive Firing

Channels that cannot inactivate leave the membrane depolarized and firing repetitively. Because sodium-channel fast inactivation is what terminates every action potential, disabling it converts a single stimulus into a train - the cellular event underlying the whole syndrome.

sympathetic postganglionic neuron CL:0011103

membrane depolarization during action potential GO:0086010 ↑ INCREASED

Downstream

Autonomic Neurotransmitter Storm Repetitive firing at autonomic terminals is what empties them.

Show evidence (1 reference)

PMID:30733386 SUPPORT In Vitro

"Fast inactivation of voltage-gated sodium (Nav) channels is essential for electrical signaling"

Why disabling inactivation is not a subtle perturbation: it removes the mechanism that ends each action potential.

Autonomic Neurotransmitter Storm

Both divisions of the autonomic nervous system discharge at once. Sympathetic terminals and the adrenal medulla release catecholamines while parasympathetic terminals release acetylcholine, so the clinical picture is not a coherent adrenergic or cholinergic syndrome but both superimposed - tachycardia with hypersalivation, hypertension with vomiting, sweating with bradycardia.

Catecholamine storm drives the fatal cardiac dysfunction

adrenal medulla chromaffin cell CL:0000336

catecholamine secretion GO:0050432 ↑ INCREASED acetylcholine secretion GO:0061526 ↑ INCREASED

Animal models

Lethally envenomed C57BL/6 mouse (Tityus serrulatus venom, 180 ug/kg i.p.) Mouse recapitulates Both arms of the storm are reproduced and measured directly in plasma - adrenaline and acetylcholine together - alongside the autonomic clinical signs that define the syndrome in people.

Downstream

Catecholamine-Mediated Myocardial Injury The adrenergic arm, and the one the canonical account holds responsible.

Fasciculations

Tremor

Acute pancreatitis Drawn as an indirect edge with unknown intermediates on purpose. The human study establishes pancreatic injury after envenomation and proposes no route to it; the murine IL-1 receptor and nitric-oxide work concerns islet function rather than acinar damage, so nothing in the entry's sources identifies what connects the storm to the pancreas.

Hyperglycemia

Hyperhidrosis

Excessive salivation

Vomiting

Priapism

Tachycardia

Bradycardia

Hypertension

Show evidence (2 references)

PMID:33116136 SUPPORT Model Organism

"We detected a dramatic increase in the concentration of adrenaline and ACh compared to PBS-inoculated mice"

Measures both arms of the storm simultaneously in plasma, which is the claim this node makes - not that one or other transmitter rises.

PMID:34055554 SUPPORT REVIEW SYNTHESIS Human Clinical

"The toxin released by the sting stimulates the autonomic nervous system (ANS), sympathetic and parasympathetic, which activates the coagulation cascade."

The same dual activation stated for the human disease.

Catecholamine-Mediated Myocardial Injury

Sustained adrenergic stimulation injures the myocardium by three routes that the literature has not fully separated: a direct adrenergic myocarditis, a toxic myocarditis attributed to venom itself, and myocardial ischaemia driven by raised oxygen demand together with cytokine and neuropeptide Y effects on the coronary vessels.

Catecholamine storm drives the fatal cardiac dysfunction

cardiac muscle cell CL:0000746

heart UBERON:0000948

Downstream

Cardiac Dysfunction and Pulmonary Edema

Myocarditis

Show evidence (1 reference)

PMID:15687982 SUPPORT REVIEW SYNTHESIS Human Clinical

"Adrenergic myocarditis, toxic myocarditis and myocardial ischemia are the 3 mechanisms that explain the cardiac dysfunction."

The three convergent routes this node bundles, named as three rather than resolved into one - which is the state of the evidence.

Venom-Triggered Cardiac IL-1R Signaling and PGE2 Production

Venom reaching the heart is sensed as a danger signal. Cardiac fibroblasts and resident macrophages produce IL-1 beta through an NLRP3-, ASC- and caspase-1-dependent route and prostaglandin E2 alongside it, and IL-1 receptor signalling is required to sustain the PGE2 output. This node is the entry point of the emerging hypothesis arm and is demonstrated only in mice.

An IL-1R/PGE2/acetylcholine neuro-immune axis drives it instead

cardiac fibroblast CL:0002548

prostaglandin E2 biosynthesis in the envenomed heart GO:0001516 ↑ INCREASED

Animal models

Lethally envenomed C57BL/6 mouse (Tityus serrulatus venom, 180 ug/kg i.p.) Mouse recapitulates This node exists only because of this model. Every step of it - the inflammasome-dependent IL-1 beta, the sustained PGE2, and the IL-1R requirement - was established here and has never been shown in a person.

Downstream

Excessive Vagal Acetylcholine Release at the Heart

Show evidence (1 reference)

PMID:33116136 SUPPORT Model Organism

"TsV increased NLRP3, Asc, and Casp1/11−dependent IL-1β release"

The inflammasome dependency that grounds this node's conformance to the NLRP3 module. The three gene names qualify "dependent IL-1 beta release": the claim is that release required NLRP3, ASC and caspase-1, which is assembly-and-activation evidence rather than transcript upregulation. The character between "11" and "dependent" is U+2212 MINUS SIGN as the source renders it, not a hyphen.

Excessive Vagal Acetylcholine Release at the Heart

The cholinergic arm of the emerging account. Parasympathetic output to the heart is driven beyond the range the organ tolerates, producing the bradycardia and arrhythmia of the syndrome and, in mice, the fatal cardiac dysfunction itself.

An IL-1R/PGE2/acetylcholine neuro-immune axis drives it instead

acetylcholine secretion GO:0061526 ↑ INCREASED

Downstream

Cardiac Dysfunction and Pulmonary Edema The claim that distinguishes this hypothesis from the canonical one: the heart failure is cholinergic in origin.

Show evidence (1 reference)

PMID:33116136 SUPPORT Model Organism

"PGE2 signaling via EP2/4 receptors mediates excessive ACh release, which in turn causes the heart failure of envenomed mice"

Establishes this node directly - that acetylcholine release is driven to excess and that it is what produces the heart failure. The haemodynamic measurement is cited on the animal model instead, where it sits before the mechanism is established and so cannot carry it.

Cardiac Dysfunction and Pulmonary Edema

The convergence point of both hypothesis arms and the proximate cause of almost every scorpion-sting death. Left ventricular failure with pulmonary oedema develops within hours, is far commoner in children, and is reversible in survivors - left ventricular function recovers in almost all who live.

lung UBERON:0002048

Animal models

Lethally envenomed C57BL/6 mouse (Tityus serrulatus venom, 180 ug/kg i.p.) Mouse partially recapitulates Envenomed mice develop falling arterial pressure and heart rate within an hour and die, which is the cardiovascular collapse this node describes.

Downstream

Pulmonary edema

Hypotension

Show evidence (5 references)

PMID:33116136 SUPPORT BACKGROUND Human Clinical

"Major clinical manifestations that precede death after scorpion envenomation include heart failure and pulmonary edema."

Identifies this node as the terminal one. BACKGROUND because it is the mouse paper's framing of the human disease rather than its own finding.

PMID:34055554 SUPPORT REVIEW SYNTHESIS Human Clinical

"Scorpion envenomation is especially fatal in the first hours, usually due to respiratory and/or cardiovascular collapse."

The timing and the mode of death this node produces.

PMID:37018229 SUPPORT Human Clinical

"Almost all survived cases showed rapid recovery and improvement in the left ventricular function."

The reversibility that makes supportive care worth escalating: the myocardial failure is not structural damage.

+ 2 more references

Cytolytic Venom Membrane Damage

The Hemiscorpius lepturus branch, and the point at which this subtype leaves the rest of the entry. The venom is cytolytic rather than neurotoxic, lysing cell membranes at the sting site and in the circulation. The sting itself is characteristically not painful, which is why presentation is late.

Downstream

Intravascular Hemolysis with Acquired ADAMTS13 Deficiency

Skin ulcer

Show evidence (1 reference)

PMID:9679690 SUPPORT Human Clinical

"HL venom is cytotoxic, and HL is the only scorpion whose venom induces a toxic reaction."

The venom property this branch turns on.

Intravascular Hemolysis with Acquired ADAMTS13 Deficiency

Haemolysis is followed by a fall in ADAMTS13 together with an anti-ADAMTS13 IgG in almost every severe case - an acquired, antibody-mediated deficiency of the von Willebrand factor-cleaving protease rather than consumption alone. The deficiency tracks the renal outcome exactly: every child with acute kidney injury had it, and no child with normal ADAMTS13 developed renal failure.

Downstream

Thrombotic Microangiopathy and Acute Kidney Injury

Show evidence (2 references)

PMID:23893367 SUPPORT Human Clinical

"ADAMTS13 was decreased in 91.7 % of patients and the anti-ADAMTS13 antibody (Ab) was increased in 98.3 %."

The node's actual claim, quantified: the protease falls and the autoantibody rises in almost every severe case, which is what makes this an acquired antibody-mediated deficiency rather than consumption alone.

PMID:23893367 SUPPORT Human Clinical

"Sixty scorpion stung children who were referred with severe hemolysis and hemoglobinuria were studied."

The cohort and the presenting haemolysis this node records.

Thrombotic Microangiopathy and Acute Kidney Injury

The terminal node of the cytotoxic branch: disseminated intravascular coagulation and haemolytic uraemic syndrome, with acute kidney injury in about a quarter of severe cases.

kidney UBERON:0002113

Downstream

Acute kidney injury

Hemolytic-uremic syndrome

Thrombocytopenia

Show evidence (1 reference)

PMID:23893367 SUPPORT Human Clinical

"Acute kidney injury was found in 23.3 % and had significant association with severe anemia, thrombocytopenia, pyuria, hematuria and considerable proteinuria"

The haematological and renal findings that define this node.

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Pathograph

Use the checkboxes to hide or show graph categories. Hover nodes for evidence and cross-linked metadata.

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Phenotypes

19

Blood 1

Thrombocytopenia HP:0001873

Show evidence (1 reference)

PMID:23893367 SUPPORT Human Clinical

"Acute kidney injury was found in 23.3 % and had significant association with severe anemia, thrombocytopenia, pyuria, hematuria and considerable proteinuria"

Names thrombocytopenia among the findings associated with the renal outcome in this series.

Cardiovascular 5

Tachycardia HP:0001649

Show evidence (1 reference)

PMID:37018229 SUPPORT Human Clinical

"The most common ECG findings are sinus tachycardia (82%) followed by ST-T changes (64.6%)."

Frequency in the 703-case myocarditis series.

Bradycardia HP:0001662

Show evidence (1 reference)

PMID:37902581 SUPPORT BACKGROUND Human Clinical

"profuse and uncontrollable vomiting, profuse sweating, intense sialorrhea, prostration, seizures, coma, bradycardia, heart failure, severe pulmonary edema and shock"

Lists bradycardia among the features defining the severe grade.

Hypertension HP:0000822

Show evidence (1 reference)

PMID:37902581 SUPPORT BACKGROUND Human Clinical

"the accident is considered mild if it only presents local pain, with or without paresthesia; moderate, if there is severe local pain and systemic manifestations (slight sweating, nausea, occasional vomiting, tachycardia, tachypnea, and hypertension)"

Lists hypertension among the systemic manifestations defining the moderate grade.

Hypotension HP:0002615

Show evidence (1 reference)

PMID:37018229 SUPPORT Human Clinical

"Myocarditis associated with scorpion envenomation was usually reported in children presenting with cardiopulmonary symptoms including pulmonary edema (60.7%) and shock or hypotension (45.8%)."

Frequency of shock among the myocarditis cases, and its co-occurrence with pulmonary oedema.

Myocarditis HP:0012819

Show evidence (1 reference)

PMID:37018229 SUPPORT Human Clinical

"Mortality in confirmed scorpion-related myocarditis cases is estimated at 7.3%."

The case fatality once myocarditis is established, which is what makes this phenotype the one that matters prognostically.

Digestive 2

Vomiting HP:0002013

Show evidence (1 reference)

PMID:37902581 SUPPORT BACKGROUND Human Clinical

"the accident is considered mild if it only presents local pain, with or without paresthesia; moderate, if there is severe local pain and systemic manifestations (slight sweating, nausea, occasional vomiting, tachycardia, tachypnea, and hypertension)"

Vomiting appears at the moderate grade in this grading scheme and becomes uncontrollable at the severe one.

Acute pancreatitis HP:0001735

Show evidence (1 reference)

PMID:2028471 SUPPORT PRIMARY RESULT Human Clinical

"High ICT levels were found in 13 children (93%), indicating that acute pancreatitis is a common complication of envenomation by this scorpion."

Immunoreactive cationic trypsin raised in 13 of 14 envenomed children, which is a biochemical measure of pancreatic injury rather than a clinical impression.

Genitourinary 3

Priapism HP:0200023

Acute kidney injury HP:0001919

Show evidence (1 reference)

PMID:23893367 SUPPORT Human Clinical

"ADAMTS13 decreased in all of the patients with acute kidney injury and none of those with normal levels of ADAMTS13 developed renal failure"

Establishes the renal outcome in this cohort and its complete dependence on the ADAMTS13 fall.

Hemolytic-uremic syndrome HP:0005575

Show evidence (1 reference)

PMID:23893367 SUPPORT Human Clinical

"all patients with AKI had also increased levels of ADAMTS13Ab"

The antibody-mediated ADAMTS13 deficiency that underlies the microangiopathic picture this phenotype names.

Head and Neck 1

Excessive salivation HP:0003781

Show evidence (1 reference)

PMID:37902581 SUPPORT BACKGROUND Human Clinical

"profuse and uncontrollable vomiting, profuse sweating, intense sialorrhea, prostration, seizures, coma, bradycardia, heart failure, severe pulmonary edema and shock"

Lists intense sialorrhea among the features defining the severe grade.

Integument 2

Hyperhidrosis HP:0000975

Show evidence (1 reference)

PMID:37902581 SUPPORT BACKGROUND Human Clinical

"the accident is considered mild if it only presents local pain, with or without paresthesia; moderate, if there is severe local pain and systemic manifestations (slight sweating, nausea, occasional vomiting, tachycardia, tachypnea, and hypertension)"

Sweating appears at the moderate grade and becomes profuse at the severe one, in the same national grading scheme.

Skin ulcer HP:0200042

Show evidence (1 reference)

PMID:9679690 SUPPORT Human Clinical

"Erythema, purpuric changes, bullae, necrosis, and ulcers, or a combination of these, may be seen at different stages."

The staged local lesion this phenotype records.

Metabolism 2

Pulmonary edema HP:0100598

Temporal: ACUTE

Show evidence (1 reference)

PMID:37018229 SUPPORT Human Clinical

"Myocarditis associated with scorpion envenomation was usually reported in children presenting with cardiopulmonary symptoms including pulmonary edema (60.7%) and shock or hypotension (45.8%)."

Frequency in the same series.

Hyperglycemia HP:0003074

Show evidence (2 references)

PMID:32150895 SUPPORT Model Organism

"Il1r1-/- mice were protected from transitory hyperglycemia and did not present disturbances in insulin levels in the serum."

An IL-1 receptor knockout abolishes the hyperglycaemia, which is what puts this phenotype on the inflammatory arm rather than purely on the catecholamine one.

PMID:32150895 SUPPORT BACKGROUND Human Clinical

"Among these events, transitory hyperglycemia is a severe manifestation that influences pulmonary edema, hemodynamic alterations, and cardiac disturbances."

Why the sign matters clinically rather than being an incidental laboratory finding. BACKGROUND: the mouse paper's framing, not its result.

Nervous System 3

Local paresthesia at bite site HP:0020014

Temporal: ACUTE

HPO's term is worded for a bite; the sting is the same clinical entity and HPO carries no sting-specific counterpart. `runoak`/OLS `q=sting, ontology=hp` returns only `HP:6000420` Burning eye sensation and a CHEBI formic-acid hit, and `q=envenomation, ontology=hp` returns nothing, so the specificity is carried in `preferred_term`.

Show evidence (1 reference)

PMID:37902581 SUPPORT BACKGROUND Human Clinical

"the accident is considered mild if it only presents local pain, with or without paresthesia; moderate, if there is severe local pain and systemic manifestations (slight sweating, nausea, occasional vomiting, tachycardia, tachypnea, and hypertension)"

Places local pain with or without paraesthesia as the defining feature of the mild grade, that is, the floor of the clinical spectrum.

Fasciculations HP:0002380

Show evidence (1 reference)

PMID:34055554 SUPPORT REVIEW SYNTHESIS Human Clinical

"Guillain-Barre-like syndrome, myelitis, abnormal eye movements, facial and eye paralysis, fasciculations, and muscle jerks simulating seizures have been reported."

Names fasciculations among the reported neurological manifestations of severe envenomation.

Tremor HP:0001337

Show evidence (1 reference)

PMID:32899951 SUPPORT REVIEW SYNTHESIS Human Clinical

"This excessive release of neurotransmitters provokes an autonomic storm consisting of cardiovascular (tachycardia, peripheral vasoconstriction, hypertension, diaphoresis), metabolic (hyperthermia, hyperglycemia), urogenital (bladder dilatation, urinary retention, ejaculation in males),..."

Attributes tremor to the neurotransmitter release this entry calls the autonomic storm, which is the node it is wired from.

💊

Medical Actions

8

Species-specific antivenom

Action: antivenom administration Ontology label: Pharmacotherapy NCIT:C15986

Platform: Other

Equine F(ab')2 or Fab antivenom against the local species, the only treatment that removes venom rather than opposing its effects. In the pivotal paediatric trial it cleared the clinical syndrome within four hours in every recipient and made circulating venom undetectable, against one of seven on placebo.

Mechanism Target:

INHIBITS Scorpion Venom Neurotoxin Binding to Voltage-Gated Sodium Channels — Antivenom binds circulating venom, so it acts upstream of the channel - which is also why it cannot reverse what the channel has already set in motion.

Show evidence (1 reference)

PMID:19439743 SUPPORT Human Clinical

"Plasma venom concentrations were undetectable in all eight antivenom recipients but in only one placebo recipient 1 hour after treatment (P=0.001)."

Measures the effect on circulating venom directly, which is the mechanism this edge asserts rather than the clinical endpoint.

Show evidence (4 references)

PMID:19439743 SUPPORT Human Clinical

"The clinical syndrome resolved more rapidly among recipients of the antivenom than among recipients of placebo, with a resolution of symptoms in all eight antivenom recipients versus one of seven placebo recipients within 4 hours after treatment (P=0.001)."

The randomised, placebo-controlled result behind this treatment.

PMID:24550184 SUPPORT Human Clinical

"The proportion of children deteriorating to clinical grade 3 or 4 was 8% in group A as against 44% in group B (p<0.01)."

A second randomised trial, in children and against a different species, measuring the outcome that matters most here - progression to the severe grades rather than symptom resolution.

PMID:28390429 SUPPORT PRIMARY RESULT Human Clinical

"Antivenom against Centruroides sp. are effective in reversing the clinical syndrome faster than no antivenom treatment in children (RR, 0.02; 95% CI, 0.01 to 0.06; 322 participants; three trials)."

The pooled estimate across three trials and 322 children, which is the strongest form the antivenom claim takes. Note the scope: this is Centruroides, and the same meta-analysis reaches a separate conclusion for Mesobuthus tamulus, where antivenom is an add-on to prazosin rather than a standalone.

+ 1 more reference

Prazosin

Action: Pharmacotherapy NCIT:C15986

Agent: prazosin CHEBI:8364

Platform: Small molecule

An alpha-1 adrenergic antagonist, oral, and cheap. It opposes the adrenergic arm of the storm directly and is the established treatment for Mesobuthus tamulus stings in India, where it is often given without antivenom at all.

Mechanism Target:

INHIBITS Catecholamine-Mediated Myocardial Injury — Blocking alpha-1 receptors opposes the vasoconstriction and afterload rise through which the catecholamine surge injures the myocardium. Note this edge is drawn under the canonical hypothesis; under the emerging one prazosin would be treating an arm that is not the lethal one.

Show evidence (1 reference)

PMID:21209062 SUPPORT INDIRECT Human Clinical

"Recovery from scorpion sting is hastened by simultaneous administration of scorpion antivenom plus prazosin compared with prazosin alone."

Prazosin resolving the autonomic syndrome in both arms of a randomised trial. INDIRECT: a therapeutic response cited as validation of the mechanism it targets, and this design compares adding antivenom rather than prazosin against nothing.

Show evidence (2 references)

PMID:21209062 SUPPORT Human Clinical

"Recovery from scorpion sting is hastened by simultaneous administration of scorpion antivenom plus prazosin compared with prazosin alone."

The randomised comparison that positions prazosin: effective enough to be the control arm, and improved on by adding antivenom.

PMID:21209062 SUPPORT Human Clinical

"Mean (SD) recovery times in hours for the prazosin plus scorpion antivenom group compared with the prazosin alone groups were: sweating 3 (1.1) v 6.6 (2.6); salivation 1.9 (0.9) v 3 (1.9); priapism 4.7 (1.5) v 9.4 (1.5)."

Resolution times for three autonomic signs in both arms. Read carefully: the trial has no placebo, so these numbers measure what adding antivenom does on top of prazosin, and the prazosin-alone arm is the slower one. Cited here because it shows prazosin alone resolving the storm's signs within hours, not because it isolates prazosin's effect - which this design cannot do.

Dobutamine

Action: Pharmacotherapy NCIT:C15986

Agent: dobutamine CHEBI:4670

Platform: Small molecule

A beta-1 agonist inotrope for the myocardial depression and cardiogenic shock of severe envenomation - supporting the failing ventricle rather than acting on the venom or the storm.

Mechanism Target:

MODULATES Cardiac Dysfunction and Pulmonary Edema — Dobutamine acts on neither the venom nor the storm. It supports the failing ventricle at the node where both hypothesis arms converge, which is why it is drawn here and nowhere upstream. MODULATES rather than INHIBITS: beta-1 agonism raises cardiac output against a depressed myocardium, it does not remove the cause of the depression.

Show evidence (1 reference)

PMID:32428515 SUPPORT DIRECT PRIMARY RESULT Human Clinical

"Our study confirms that cardiac dysfunction following scorpion envenomation in Tunisia improved well and safely under dobutamine infusion."

Measures the effect on this node directly - cardiac index rose from 2.7 to 3.6 L/min/m2 at the lowest dose - in 21 Swan-Ganz-monitored patients, which is the claim this edge makes.

Show evidence (3 references)

PMID:32428515 SUPPORT PRIMARY RESULT Human Clinical

"We included 21 patients with pulmonary edema or hemodynamic shock following scorpion envenoming."

The dedicated dobutamine study, and its population: every patient had the pulmonary oedema or shock this treatment is for. An uncontrolled dose-ranging series, not a trial.

PMID:32428515 SUPPORT PRIMARY RESULT Human Clinical

"The optimal dose of dobutamine to start with was between 5 and 10 μg/kg/min."

The dosing conclusion, which is the practical output of the study. Quoted with the source's own non-breaking space before the unit, since the reference validator matches bytes.

PMID:37018229 SUPPORT Human Clinical

"The management typically included inotropes (especially dobutamine), prazosin, diuretics, nitroglycerine and digoxin, when indicated."

Places dobutamine as the usual inotrope in the reviewed cases.

Mechanical ventilation and intensive supportive care

Action: Mechanical Ventilation NCIT:C70909

Platform: Device

Required in about a third of the myocarditis cases, and the reason outcome depends so heavily on how far the patient is from an intensive care bed.

Mechanism Target:

MODULATES Cardiac Dysfunction and Pulmonary Edema — Ventilation takes over gas exchange against the alveolar flooding this node produces. It acts on the consequence, not on the failing ventricle, and nothing it does shortens the myocardial recovery - which is why the edge is MODULATES and why outcome tracks distance from an intensive care bed rather than anything pharmacological.

Show evidence (1 reference)

PMID:37018229 SUPPORT INDIRECT Human Clinical

"Mechanical ventilation was required in 36.7% of the patients."

INDIRECT, and the limit is worth stating: this establishes that the myocarditis at this node is what drives the need for ventilation in over a third of cases. No cited source here measures what ventilation does to the node once started.

Show evidence (1 reference)

PMID:37018229 SUPPORT Human Clinical

"Mechanical ventilation was required in 36.7% of the patients."

The proportion needing ventilation, in the pooled myocarditis series.

Early dexamethasone

Action: Pharmacotherapy NCIT:C15986

Agent: dexamethasone CHEBI:41879

Platform: Small molecule

Not established practice. In envenomed mice, high-dose dexamethasone abolished heart failure and mortality, and the authors propose giving it very early - before antiserum - on the grounds that it reaches a pathway antivenom does not. Recorded because it is a mechanism-directed proposal with a specific rationale, not because there is human evidence for it.

Mechanism Target:

INHIBITS Venom-Triggered Cardiac IL-1R Signaling and PGE2 Production — Suppressing the inflammatory arm at its origin, which is where the emerging hypothesis locates the lethal pathway.

Show evidence (1 reference)

PMID:33116136 SUPPORT Model Organism

"IL-1R deficiency, the treatment with a high dose of dexamethasone or blockage of parasympathetic signaling using atropine or vagotomy, abolished heart failure and mortality of envenomed mice."

Dexamethasone is one of four interventions abolishing the outcome, which is what makes this a mechanism-directed edge rather than an empirical one.

Show evidence (3 references)

PMID:33116136 SUPPORT Model Organism

"we propose the use of dexamethasone administration very early after envenomation, even before antiserum"

The proposal itself, quoted so the entry records it as the authors' recommendation from a mouse model rather than as practice.

PMID:33116136 SUPPORT Model Organism

"we introduce a novel pathway that is targeted by dexamethasone, but not by anti-scorpion venom serum"

The argument for adding it rather than relying on antivenom: the two act on different things.

PMID:39628768 SUPPORT REVIEW SYNTHESIS Other

"In recent decades, new research has revealed that the immune system plays an important role in triggering immunopathological reactions during scorpion envenoming, which places it as a therapeutic target; however, few clinical studies have been conducted."

Confirms both halves of this treatment's status: the immune system is taken seriously as a target, and the clinical evidence for acting on it does not yet exist. Graded OTHER because the quoted sentence is a review's assessment of a field rather than a described study.

Atropine

Action: Pharmacotherapy NCIT:C15986

Agent: atropine CHEBI:16684

Platform: Small molecule

The drug the two hypotheses disagree about most sharply. In envenomed mice it is one of four interventions that abolish cardiac failure and death, and the emerging hypothesis predicts it should work. In human practice it is advised against for routine use - it blocks sweating, which children need for temperature regulation, and it potentiates the adrenergic arm the canonical hypothesis holds responsible. Both positions are curated here because the disagreement is the point: the same drug is protective or harmful depending on which arm is lethal.

Mechanism Target:

INHIBITS Excessive Vagal Acetylcholine Release at the Heart — Muscarinic blockade at the heart, which is the effector step of the emerging hypothesis. This edge is drawn under that hypothesis; under the canonical one atropine is acting on an arm that is not the lethal one, and unopposing the one that is.

Show evidence (1 reference)

PMID:33116136 SUPPORT PRIMARY RESULT Model Organism

"Interestingly, in contrast to treatment with propranolol, the administration of atropine, a nonselective muscarinic antagonist, rescued the mice from mortality"

The comparison that makes this edge mechanistic rather than empirical: blocking the parasympathetic arm rescued the mice where blocking the sympathetic arm did not.

Show evidence (2 references)

PMID:22826633 REFUTE REVIEW SYNTHESIS Other

"In general, antiparasympathetic drugs, such as atropine, are not recommended routinely in the treatment of scorpion envenoming."

The standing human recommendation, and it is against routine use. REFUTE against treating atropine as an established therapy here. Graded OTHER because the quoted sentence is a review's recommendation rather than a described study.

PMID:22826633 SUPPORT REVIEW SYNTHESIS Other

"However, these drugs can be useful in cases of severe bradycardia or complete atrioventricular block, which are sometimes observed."

The narrow indication the same review does accept, quoted so the entry records what atropine is actually used for rather than only what it is advised against.

Plasma exchange and renal replacement therapy

Action: therapeutic plasma exchange Ontology label: Plasmapheresis NCIT:C15304

Platform: Device

Supportive treatment of the cytotoxic branch once thrombotic microangiopathy and renal failure are established. Curated because that branch otherwise reaches its terminal nodes with nothing acting on it, and because the mechanism the entry curates - an acquired ADAMTS13 deficiency with an autoantibody against the enzyme - is the same one plasma exchange addresses in the primary thrombotic microangiopathies, by removing the antibody and replacing the enzyme.

Mechanism Target:

MODULATES Thrombotic Microangiopathy and Acute Kidney Injury — Acting at the terminal node of the cytotoxic branch rather than upstream of it: by the time plasma exchange is started the venom has already lysed the erythrocytes. Read the evidence carefully - the cited case establishes that the combination was given and the child recovered, not that plasma exchange is what produced the recovery. No controlled evidence exists for it in this disease.

Show evidence (1 reference)

PMID:40034936 SUPPORT INDIRECT PRIMARY RESULT Human Clinical

"The patient received supportive treatment, hemodialysis, and plasma exchange, and was discharged after 30 days of hospitalization."

A single case report of use with survival. INDIRECT: an uncontrolled therapeutic response cited in support of the mechanism it is thought to act on, with three interventions given together and no way to separate them.

Anti-heminecrolysin nanobody

Action: Pharmacotherapy NCIT:C15986

Platform: Nanobody

A candidate, not a treatment. Heminecrolysin is the haemolytic and dermonecrotic fraction of Hemiscorpius lepturus venom - the molecule behind the cytotoxic branch - and a camelid single-domain antibody against it neutralised both activities in mice. Recorded because it is the only agent in the entry aimed at the cytolytic lesion itself rather than at its consequences, and because the equine antivenom it would replace causes anaphylaxis.

Mechanism Target:

INHIBITS Cytolytic Venom Membrane Damage — Neutralising the venom fraction that does the lysing, upstream of the haemolysis - which is the one point on this branch where a treatment could act before the damage rather than after it.

Show evidence (1 reference)

PMID:24891523 SUPPORT PRIMARY RESULT Model Organism

"The in vivo neutralization tests demonstrated that F7Nb had good antihemolytic and antidermonecrotic effects against HNc in all tested mice."

Both activities of the toxin neutralised in vivo, which is the claim this edge makes. Mouse only.

Show evidence (2 references)

PMID:24891523 SUPPORT PRIMARY RESULT Model Organism

"Hence, this Nb is a potential leading novel candidate for treating H. lepturus scorpionism in the near future."

The authors' own statement of where this stands - a candidate for development, quoted so the entry does not read it as available therapy.

PMID:24891523 SUPPORT BACKGROUND Other

"However, this immunotherapy creates serious side effects, including anaphylactic shock sometimes even leading to death."

The problem with the existing equine antivenom that motivates a replacement. BACKGROUND: the paper's framing of the clinical situation, not its own result. Graded OTHER because the quoted sentence names an adverse-effect profile without describing the study behind it.

🌍

Environmental Factors

2

Scorpion sting delivering neurotoxic venom

Hazard type: BIOLOGICAL

Duration: ACUTE

Bound to `ECTO:0000730` exposure to neurotoxin, anchored on `CHEBI:50910` neurotoxin, which is exact for the agent class: the buthid venom's active principles are sodium-channel neurotoxins. ECTO has no scorpion, venom or sting class. The searches, against the pinned local build the validator reads: `runoak -i sqlite:obo:ecto search 'l~scorpion'` returns nothing. `runoak -i sqlite:obo:ecto search 'l~venom'` returns nothing. `runoak -i sqlite:obo:ecto search 'l~arthropod'` returns nothing. `runoak -i sqlite:obo:ecto search 'l~bite'` returns nothing. `runoak -i sqlite:obo:ecto search 'l~sting'` returns only `ENVO:01000690` mass wasting and `XCO:0000002` resting, both substring false positives. `runoak -i sqlite:obo:ecto search 't~exposure to neurotoxin'` returns `ECTO:0000730`, and `info ECTO:0000730 -O obo` shows it is `is_a ECTO:0000485` exposure to chemical with biological effect and involves `CHEBI:50910` neurotoxin. Neither it nor its parent is flagged Not4Curation.

The exposure is an injection, not an ingestion or an inhalation, which is why dose scales with body mass and why children are the ones who die. Stings are domestic and rural in the great majority, concentrated in seven regions covering some 2.3 billion people.

Show evidence (1 reference)

PMID:18579104 SUPPORT REVIEW SYNTHESIS Human Clinical

"These involve 2.3 billion at risk population."

The size of the exposed population across the seven identified risk regions.

Mechanism Target:

TRIGGERS Scorpion Venom Neurotoxin Binding to Voltage-Gated Sodium Channels — The sting is what delivers the toxins to the channels; there is no other route into this disease.

Show evidence (1 reference)

PMID:34055554 SUPPORT REVIEW SYNTHESIS Human Clinical

"The toxin released by the sting stimulates the autonomic nervous system (ANS), sympathetic and parasympathetic, which activates the coagulation cascade."

States the sting-to-mechanism step this edge asserts.

TRIGGERS Venom-Triggered Cardiac IL-1R Signaling and PGE2 Production — The inflammatory arm is drawn from the exposure rather than from the autonomic storm, because in the source it does not run through it: venom reaching the heart is recognised directly by resident cardiac cells, not by way of neurotransmitter release. An earlier draft hung this edge off the storm node while its own description said the two run in parallel, which made the graph say something the curation denied.

Show evidence (1 reference)

PMID:33116136 SUPPORT Model Organism

"Cardiac fibroblasts respond to TsV and produce PGE2 and IL-1β in vitro."

The venom is sensed by cardiac cells directly, which is what makes this an edge from the exposure rather than from the neurotransmitter storm.

Scorpion sting delivering cytotoxic venom

Hazard type: BIOLOGICAL

Duration: ACUTE

Bound one level broader than the neurotoxic exposure, to `ECTO:0000537` exposure to toxin, because the agent here is a cytolytic enzyme rather than a neurotoxin and `ECTO:0000730` would be wrong. `runoak -i sqlite:obo:ecto search 't~exposure to toxin'` returns `ECTO:0000537`; the same searches recorded on the neurotoxic exposure above show ECTO has no cytotoxin, phospholipase or venom class to be more specific with.

The same act with a different venom. Hemiscorpius lepturus accounts for about a tenth of stings in Khuzestan and for essentially all of the cutaneous and haemolytic disease there.

Show evidence (1 reference)

PMID:9679690 SUPPORT Human Clinical

"Hemiscorpion (Hemiscorpius) lepturus (HL), which is responsible for more than 10% of the scorpion stings in this area"

States this exposure's share of stings in the studied region directly, rather than leaving it to be derived as the complement of the buthid 90%.

Mechanism Target:

TRIGGERS Cytolytic Venom Membrane Damage — The cytolytic venom is delivered by the same sting route.

🔬

Biochemical Markers

5

N-terminal pro-B-type natriuretic peptide (NT-proBNP) (INCREASED)

Pathograph Readouts

Predicts Cardiac Dysfunction and Pulmonary Edema Positive Prognostic

An admission NT-proBNP identifies the children who will develop cardiotoxicity, hours before echocardiography or the clinical picture does.

Show evidence (2 references)

PMID:33094659 SUPPORT PRIMARY RESULT Human Clinical

"NT-proBNP may be a valuable and sensitive laboratory biomarker to predict cardiotoxicity of scorpion sting in the early hours."

The authors' own statement of the prognostic claim this readout makes.

PMID:33994108 SUPPORT PRIMARY RESULT Human Clinical

"ProBNP 1 was significantly higher in the severe group at admission (P=0.016)."

A second, independent paediatric series reaching the same conclusion from the admission value, against a severity grading rather than against a cardiac endpoint.

Correlates With Cardiac Dysfunction and Pulmonary Edema Negative Diagnostic

The level tracks inversely with measured ventricular performance, which is what makes it a readout of this node rather than a general severity marker.

Show evidence (1 reference)

PMID:33994108 SUPPORT PRIMARY RESULT Human Clinical

"There was a negative correlation between proBNP and echocardiographic findings involving ejection fraction and shortening fraction (r=-0.703, P=0.002)."

Ties the marker directly to ejection and shortening fraction, which is the node this readout points at. Direction is NEGATIVE because the quantity correlated is preserved function, not injury.

Show evidence (2 references)

PMID:33094659 SUPPORT PRIMARY RESULT Human Clinical

"Assessment of NT-proBNP levels showed a significant increase in all moderate to severe cases on admission and 6 h post-envenomation."

The elevation itself, in a prospective series of 483 stung children, and present already on admission rather than only at six hours.

PMID:33094659 SUPPORT PRIMARY RESULT Human Clinical

"The sensitivity of NT-proBNP for the diagnosis of myocardial injury at hospital admission was significantly higher than that of CPK-MB."

The head-to-head comparison against the other marker curated here, in the same patients and at the same time point.

Creatine kinase MB (CK-MB) (INCREASED)

Pathograph Readouts

Readout Of Catecholamine-Mediated Myocardial Injury Positive Diagnostic

CK-MB release reports myocardial cell injury, which is the lesion this node asserts, rather than the ventricular failure it produces.

Show evidence (1 reference)

PMID:33094659 SUPPORT PRIMARY RESULT Human Clinical

"Assessment of CPK-MB levels showed a significant increase in all moderate to severe cases 6 h post-envenomation."

The measurement is of a cardiac-specific enzyme in circulation, so it reports myocyte membrane injury at this node.

Show evidence (1 reference)

PMID:33094659 SUPPORT PRIMARY RESULT Human Clinical

"Assessment of CPK-MB levels showed a significant increase in all moderate to severe cases 6 h post-envenomation."

The elevation, and its timing - six hours, where NT-proBNP was already raised on admission in the same cohort.

Cardiac troponin (INCREASED)

Pathograph Readouts

Readout Of Cardiac Dysfunction and Pulmonary Edema Positive Diagnostic

With a high-sensitivity assay, circulating troponin detects the ventricular dysfunction this node describes. Read together with the null conventional-assay result recorded above.

Show evidence (1 reference)

PMID:39842516 SUPPORT PRIMARY RESULT Human Clinical

"Ultrasensitive troponin presented an AUC of 0.89, with a sensitivity of 84.6%."

Discrimination against cardiac dysfunction identified by cardiac ultrasound, which is this node.

Show evidence (2 references)

PMID:39842516 SUPPORT PRIMARY RESULT Human Clinical

"Ultrasensitive troponin presented an AUC of 0.89, with a sensitivity of 84.6%."

The ultrasensitive assay against echocardiographically confirmed left ventricular dysfunction, and the best discrimination reported in that study.

PMID:33994108 REFUTE PRIMARY RESULT Human Clinical

"There was no difference between the troponin I values (P=0.051)."

A null result for conventional troponin I, in the same patients and at the same time point where proBNP did separate the groups. REFUTE against the claim that troponin is informative here, recorded rather than dropped - the two studies used different assays and different endpoints, which is the most likely reason they disagree.

Soluble ST2 (sST2) (INCREASED)

Pathograph Readouts

Correlates With Cardiac Dysfunction and Pulmonary Edema Positive Diagnostic

A candidate marker, not an established one: one cross-sectional single-centre study of 49 patients, without serial measurement.

Show evidence (1 reference)

PMID:39842516 SUPPORT PRIMARY RESULT Human Clinical

"The cut-off values determined for both biomarkers showed a sensitivity of 92.3%."

The sensitivity at the study's own cut-off, which is what a diagnostic readout claim rests on.

Show evidence (1 reference)

PMID:39842516 SUPPORT PRIMARY RESULT Human Clinical

"The biomarkers of sST2 and FABP-3 showed an association with left ventricular dysfunction, presenting AUCs of 0.77 and 0.81, respectively."

The result establishing sST2 as a candidate marker in this disease, with its discrimination quantified.

Heart-type fatty acid binding protein (FABP3) (INCREASED)

Pathograph Readouts

Correlates With Cardiac Dysfunction and Pulmonary Edema Positive Diagnostic

Same standing and the same limits as sST2 - 49 patients, one centre, no serial sampling - and evaluated against the same echocardiographic endpoint.

Show evidence (1 reference)

PMID:39842516 SUPPORT PRIMARY RESULT Human Clinical

"The study showed an association between sST2 and FABP-3, as well as the presence of acute cardiac dysfunction, identified by cardiac ultrasound."

The association stated against the endpoint that defines this node - acute cardiac dysfunction on ultrasound - rather than against a clinical severity grade.

Show evidence (1 reference)

PMID:39842516 SUPPORT PRIMARY RESULT Human Clinical

"The biomarkers of sST2 and FABP-3 showed an association with left ventricular dysfunction, presenting AUCs of 0.77 and 0.81, respectively."

The result establishing FABP3 as a candidate marker here, and the better discriminating of the two new markers tested.

🔬

Diagnosis

2

Transthoracic echocardiography

The reference standard the whole biochemical section is measured against, and the test that decides management: it separates the child with an autonomic syndrome who will recover from the one with left ventricular failure who needs an intensive care bed. Reversibility is the point - ventricular function recovers in almost all survivors, so a depressed ejection fraction here is a reason to escalate support rather than a prognosis.

echocardiography NCIT:C16525

Markers: Ejection fraction, shortening fraction, left ventricular dysfunction

Results: Left ventricular dysfunction in roughly a quarter of patients presenting with signs of severity.

Curated as a diagnosis rather than as a biomarker because it is the endpoint every marker in the `biochemical:` section is evaluated against - sST2 and FABP3 report AUCs against cardiac ultrasound, and proBNP is correlated against ejection and shortening fraction. Reading the two sections together, the markers are candidates for triaging who gets an echocardiogram sooner, not replacements for it.

Show evidence (2 references)

PMID:39842516 SUPPORT BACKGROUND Human Clinical

"The resources currently available for diagnosing cardiac dysfunction caused by scorpion stings, the most common cause of death, are echocardiograms and laboratory tests, such as troponin, creatine phosphokinase-MB (CKMB), and Brain natriuretic peptide (BNP)."

States the diagnostic standard of care for this disease, and names the same laboratory markers the `biochemical:` section curates. BACKGROUND because it frames the study rather than reporting its result.

PMID:39842516 SUPPORT PRIMARY RESULT Human Clinical

"Left ventricular dysfunction was identified in 13 patients (26.5%), with 7 cases classified as severe."

The yield of the test in a series selected for signs of severity on admission, which is the population it is used in.

Serial ECG and cardiac monitoring

Continuous monitoring with periodic ECG over the first 24 hours, which is the window in which the cardiac complications appear and in which almost all deaths occur.

electrocardiography NCIT:C38053

Markers: Rhythm, rate, repolarization change

Recorded because the entry carries both `Tachycardia` and `Bradycardia` phenotypes, and which of the two a patient shows is the bedside signal that most directly bears on which autonomic arm is dominant - the question the entry's two `mechanistic_hypotheses` disagree about. No cited source here claims ECG resolves that question.

Show evidence (1 reference)

PMID:33094659 SUPPORT PRIMARY RESULT Human Clinical

"subjected to 24 h cardiac monitoring with periodic ECG every 6 h"

The monitoring protocol applied to all 483 symptomatic children in this prospective series, which is what makes it the observed practice rather than a recommendation.

📊

Prevalence

2

Worldwide

Annual Incidence Not yet documented

More than 1.2 million stings a year across the seven identified risk regions. Recorded as a count rather than a rate: the source gives a global sting total against a 2.3 billion at-risk denominator that is itself an estimate, so no per-100,000 figure can be derived from it honestly.

Show evidence (1 reference)

PMID:18579104 SUPPORT REVIEW SYNTHESIS Human Clinical

"The annual number of scorpion stings exceeds 1.2 million leading to more than 3250 deaths (0.27%)."

The global sting count and case fatality this record reports.

Brazil

Annual Incidence 70.0 per 100,000 person-years 1–9 per 10,000 per year

A national rate, in contrast to the worldwide record above which is a count with no usable denominator. Recorded because Brazil is where the incidence is best measured and because the figure is rising there.

Show evidence (1 reference)

PMID:37902581 SUPPORT BACKGROUND Human Clinical

"reaching approximately 70 cases per 100,000 inhabitants-years in 2018"

The rate and its denominator, stated per inhabitant-year.

⚖️

Clinical Burden

Variable

The overwhelming majority of stings cause severe local pain and nothing else, while a small minority progress within hours to myocarditis, pulmonary oedema and death. Over 1.2 million stings a year produce more than 3250 deaths, a case fatality of 0.27% - but that figure averages across a population in which children carry almost all the mortality. No single tier represents both ends, which is what `VARIABLE` is for.

Show evidence (2 references)

PMID:18579104 SUPPORT REVIEW SYNTHESIS Human Clinical

"The annual number of scorpion stings exceeds 1.2 million leading to more than 3250 deaths (0.27%)."

The denominator and the numerator behind the low average case fatality.

PMID:18579104 SUPPORT REVIEW SYNTHESIS Human Clinical

"Although adults are more often concerned, children experience more severe envenomations and among them, mortality is higher."

The spread the average hides, and the reason a single burden tier would misdescribe this disease.

🔬

Clinical Trials

2

NCT00685230 NOT_APPLICABLE COMPLETED

The randomised, double-blind, placebo-controlled paediatric trial of Centruroides-specific F(ab')2 antivenom that established the treatment and led to US approval. Fifteen children in intensive care; resolution of the clinical syndrome within four hours was the primary endpoint.

Target Phenotypes: Local paresthesia at sting site HP:0020014

Show evidence (1 reference)

clinicaltrials:NCT00685230 SUPPORT Human Clinical

"Patients stung by Centruroides scorpions develop a clinical syndrome which may require sedation with benzodiazepines and observation for 6 to 28 hours of intensive care monitoring."

The registration's own statement of the syndrome and the standard of care this trial was testing antivenom against, which is what identifies it as the trial reported in PMID:19439743.

CTRI/2013/09/004002 NOT_APPLICABLE COMPLETED

The Indian paediatric randomised trial of scorpion antivenom plus prazosin against prazosin alone, reported in PMID:24550184. Registered on CTRI rather than ClinicalTrials.gov, which is why it is keyed on its WHO ICTRP identifier.

Show evidence (2 references)

ICTRP:CTRI/2013/09/004002 SUPPORT Other

"| Register | CTRI |"

The WHO ICTRP registration record establishing this trial's identity on a non-ClinicalTrials.gov primary registry.

ICTRP:CTRI/2013/09/004002 SUPPORT Other

"| Prospective Registration | No |"

The retrospective registration, quoted rather than asserted because it bears on how the trial's result should be read.

🐁

Animal Models

1

Lethally envenomed C57BL/6 mouse (Tityus serrulatus venom, 180 ug/kg i.p.)

The model the whole emerging hypothesis rests on. Mice given a lethal intraperitoneal dose of Tityus serrulatus venom develop sweating, ocular and nasal secretion, lethargy and convulsion within an hour, with measurable rises in plasma adrenaline and acetylcholine, falling arterial pressure and heart rate, and death in half to all animals. Its value is that it is interventional where the human literature is observational: genetic knockouts and drugs can be applied to individual steps.

Species

Mouse

Genotype

C57BL/6 wild type, with Il1r1-/-, Nlrp3-/-, Asc-/- and Casp1/11-/- knockouts used as mechanistic controls

Publication

PMID:33116136

Pathograph links

Autonomic Neurotransmitter Storm recapitulates fidelity: moderate observes: organism Both arms of the storm are reproduced and measured directly in plasma - adrenaline and acetylcholine together - alongside the autonomic clinical signs that define the syndrome in people.

Limitations: The route and dose are not those of a sting: an intraperitoneal bolus at a defined lethal dose is not a subcutaneous injection of unknown quantity, and nothing in the model reproduces the dependence on body mass that makes this a disease of children.

Readouts

Plasma adrenaline and acetylcholine

Direction: INCREASED

Interpretation: Simultaneous elevation of both transmitters is the defining measurement of this node, and the reason the entry does not treat the storm as adrenergic alone.

Show evidence (1 reference)

PMID:33116136 SUPPORT Model Organism

"We detected a dramatic increase in the concentration of adrenaline and ACh compared to PBS-inoculated mice"

The measurement itself, against a vehicle control.

Show evidence (1 reference)

PMID:33116136 SUPPORT Model Organism

"exhibited sweating, ocular secretion, nasal secretion, lethargy, and convulsion"

The autonomic clinical picture reproduced in the model, which is what makes it informative for this node.

Venom-Triggered Cardiac IL-1R Signaling and PGE2 Production recapitulates fidelity: unknown observes: cellular This node exists only because of this model. Every step of it - the inflammasome-dependent IL-1 beta, the sustained PGE2, and the IL-1R requirement - was established here and has never been shown in a person.

Limitations: Fidelity is UNKNOWN rather than low or moderate because there is no human counterpart to compare against: the one human study of this axis reports an association between circulating IL-1 beta and cardiac abnormality and does not test the pathway.

Divergences from the human mechanism

species mismatch qualifying

Tityus serrulatus is the Brazilian species this work uses, while most of the world's scorpion mortality is caused by Androctonus, Leiurus, Mesobuthus and Centruroides on other continents, whose venoms differ in toxin composition. Whether their venoms are sensed the same way by cardiac innate immunity is untested.

boundary omission qualifying

The sting is outside the model. Venom is delivered as an intraperitoneal bolus, so absorption from a subcutaneous depot, the dose actually injected by a scorpion, and the delay before care - all of which govern human outcome - are not represented.

Show evidence (1 reference)

PMID:33116136 SUPPORT Model Organism

"Here, we show that scorpion envenomation induces autonomic hyperactivation and heart inflammation in mice."

The claim this link carries, stated by the authors with its species restriction in the same sentence.

Cardiac Dysfunction and Pulmonary Edema partially recapitulates fidelity: moderate observes: organism Envenomed mice develop falling arterial pressure and heart rate within an hour and die, which is the cardiovascular collapse this node describes.

Limitations: The model's cardiac endpoint is haemodynamic collapse and death within about an hour. The human node includes pulmonary oedema and a myocarditis that is reversible over days in survivors, neither of which this model reports - so it captures the fatal arm and not the recovery arm that most patients follow.

Readouts

Mean arterial pressure and heart rate

Direction: DECREASED

Interpretation: Falling pressure and falling rate together is the haemodynamic signature the cholinergic account predicts.

Show evidence (1 reference)

PMID:33116136 SUPPORT Model Organism

"we observed cardiac disorders with diminished mean arterial pressure and heart rates"

The measured cardiovascular outcome in envenomed mice.

Show evidence (2 references)

PMID:33116136 SUPPORT Model Organism

"Lethally envenomed C57Bl/6 (WT) mice (TsV, 180"

The strain, the venom and the dose that define this model. Quoted short because the source renders the units with thin spaces and a minus-sign superscript immediately after; the full dose is stated in the model description and in `genotype` above.

PMID:33116136 SUPPORT Model Organism

"These data confirm that lethally envenomed mice present clinical autonomic manifestations similar to those observed in humans"

The authors' own fidelity claim for the model, and the basis for treating it as informative about the human syndrome at all.

{ }

Source YAML

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name: Scorpion Envenomation
creation_date: '2026-09-18T12:05:00Z'
category: Injury
description: >-
  Systemic poisoning following the sting of a scorpion, overwhelmingly of the
  family Buthidae. The venom's small peptide neurotoxins act on voltage-gated
  sodium channels of excitable membranes, and what follows is driven less by
  direct tissue injury than by the host's own response: a neurotransmitter
  storm releasing catecholamines and acetylcholine together, ending in cardiac
  dysfunction and pulmonary oedema. Stings are counted in the millions annually
  and the deaths are concentrated in children. One genus is different in kind -
  Hemiscorpius lepturus has a cytotoxic rather than a neurotoxic venom and
  causes dermonecrosis, haemolysis and thrombotic microangiopathy instead, so
  the entry models the two as separate subtypes rather than as one disease with
  a wide spectrum.
notes: >-
  No GeneReviews chapter exists for this disease, and none is expected: it is an
  acquired envenomation with no Mendelian basis, so `just check-genereviews`
  returns NO_CHAPTER for both Bookshelf collections. There is likewise no
  `genetic:` section. The research report searched for host susceptibility loci
  and found none established; the age dependence that dominates outcome is body
  mass and cardiovascular reserve rather than genotype, which is recorded in the
  `environmental` risk prose instead of being curated as disease genes.

  Three scope exclusions, recorded so they read as decisions rather than
  oversights. **Only alpha-toxins are modelled.** Scorpion venom also carries
  beta-NaTx, which shifts the sodium-channel activation threshold rather than
  blocking inactivation, and potassium-channel toxins; neither is in the
  pathograph, because the entry's chain rests on the structurally resolved
  site-3 mechanism and adding the others would mean asserting a chain the
  cited sources do not resolve. **The takotsubo analogy is not curated.**
  `PMID:26135709` proposes scorpion cardiomyopathy as a model for takotsubo
  syndrome, which is a genuinely interesting parallel to the catecholamine
  node - but it is a Letter with no abstract in PubMed, so there is nothing
  quotable and nothing can be built on it. Its cache file stays committed
  because the deep-research report cites it; it is the entry that does not,
  and this sentence is the reason. **The cytotoxic branch stops at the renal
  outcome.** Hepatotoxicity and the late necrotic ulcer's secondary infection
  are both reported for Hemiscorpius lepturus and are not modelled here.
disease_term:
  term:
    id: MONDO:0018755
    label: scorpion envenomation
  preferred_term: Scorpion envenomation
parents:
- Envenomation
clinical_burden:
  burden_level: VARIABLE
  rationale: >-
    The overwhelming majority of stings cause severe local pain and nothing
    else, while a small minority progress within hours to myocarditis,
    pulmonary oedema and death. Over 1.2 million stings a year produce more than
    3250 deaths, a case fatality of 0.27% - but that figure averages across a
    population in which children carry almost all the mortality. No single tier
    represents both ends, which is what `VARIABLE` is for.
  evidence:
  - reference: PMID:18579104
    reference_title: "Epidemiology of scorpionism: a global appraisal."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    snippet: "The annual number of scorpion stings exceeds 1.2 million leading to more than 3250 deaths (0.27%)."
    explanation: The denominator and the numerator behind the low average case fatality.
  - reference: PMID:18579104
    reference_title: "Epidemiology of scorpionism: a global appraisal."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    snippet: "Although adults are more often concerned, children experience more severe envenomations and among them, mortality is higher."
    explanation: >-
      The spread the average hides, and the reason a single burden tier would
      misdescribe this disease.
has_subtypes:
- name: Neurotoxic
  display_name: Neurotoxic envenomation (Buthidae)
  description: >-
    The form responsible for essentially all scorpion mortality worldwide.
    Buthid venom is neurotropic and not cytotoxic: it produces no local tissue
    reaction to speak of, and the illness is entirely a consequence of
    sodium-channel-driven autonomic discharge. All of the pathophysiology in
    this entry from the sodium-channel node onward describes this subtype.
  evidence:
  - reference: PMID:9679690
    reference_title: "Cutaneous manifestations of the Hemiscorpius lepturus sting: a clinical study."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Different species of the Buthidae family, which were responsible for the remaining 90% of scorpion stings, have a neurotropic and noncytotoxic venom and, as a result, induce no cutaneous reaction."
    explanation: >-
      States the defining property of this subtype and, by contrast, of the
      other one - in a series large enough to give the proportions.
- name: Cytotoxic
  display_name: Cytotoxic envenomation (Hemiscorpius lepturus)
  description: >-
    A mechanistically separate disease that happens to be caused by a scorpion.
    Hemiscorpius lepturus venom is cytolytic rather than neurotoxic, and the
    sting is characteristically not painful at the time. What follows is
    delayed dermonecrosis, intravascular haemolysis, acquired ADAMTS13
    deficiency with autoantibody, and thrombotic microangiopathy with acute
    kidney injury. None of the autonomic storm chain applies.
  evidence:
  - reference: PMID:9679690
    reference_title: "Cutaneous manifestations of the Hemiscorpius lepturus sting: a clinical study."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "HL venom is cytotoxic, and HL is the only scorpion whose venom induces a toxic reaction."
    explanation: Establishes the separate venom class this subtype turns on.
mechanistic_hypotheses:
- hypothesis_group_id: adrenergic_catecholamine_storm
  hypothesis_label: Catecholamine storm drives the fatal cardiac dysfunction
  status: CANONICAL
  description: >-
    The long-standing account. Sodium-channel toxins drive sympathetic
    terminals and the adrenal medulla to release catecholamines in bulk;
    the resulting adrenergic myocarditis, raised afterload and myocardial
    ischaemia produce left ventricular failure and pulmonary oedema. This is
    the model that motivates prazosin, and the model under which the
    alpha-1 blocker's clinical benefit is read as mechanistic confirmation.
  evidence:
  - reference: PMID:15687982
    reference_title: "[Cardiovascular dysfunction following severe scorpion envenomation. Mechanisms and physiopathology]."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    snippet: "Adrenergic myocarditis, toxic myocarditis and myocardial ischemia are the 3 mechanisms that explain the cardiac dysfunction."
    explanation: >-
      The canonical account stated as three adrenergic and ischaemic routes,
      with no cholinergic arm among them.
  - reference: PMID:37018229
    reference_title: "Scorpion envenomation-associated myocarditis: A systematic review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The management typically included inotropes (especially dobutamine), prazosin, diuretics, nitroglycerine and digoxin, when indicated."
    explanation: >-
      The practice this hypothesis generates - alpha-1 blockade and inotropic
      support - pooled across 703 human cases.
- hypothesis_group_id: il1r_pge2_cholinergic_axis
  hypothesis_label: An IL-1R/PGE2/acetylcholine neuro-immune axis drives it instead
  status: EMERGING
  description: >-
    A mouse account that puts the fatal arm on the other side of the autonomic
    nervous system. Venom recognition drives cardiac IL-1 receptor signalling
    and prostaglandin E2 production; PGE2 acting at EP2/EP4 receptors then
    drives excessive vagal acetylcholine release, and it is that cholinergic
    signal, not the adrenergic one, which produces the heart failure. Four
    independent interventions - IL-1R knockout, high-dose dexamethasone,
    atropine, and vagotomy - each abolish mortality in envenomed mice, and the
    authors note the pathway is untouched by antivenom. Recorded as EMERGING
    rather than ALTERNATIVE because nothing in it has been tested in humans.
  evidence:
  - reference: PMID:33116136
    reference_title: Interleukin-1 receptor-induced PGE(2) production controls acetylcholine-mediated cardiac dysfunction and mortality during scorpion envenomation.
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: "cardiac dysfunction and fatal outcomes caused by lethal scorpion envenomation in mice are mediated by a neuro-immune interaction linking IL-1 receptor signaling, prostaglandin E2, and acetylcholine release"
    explanation: >-
      The hypothesis in the authors' own words, with the species it was
      demonstrated in stated in the same sentence.
  - reference: PMID:33116136
    reference_title: Interleukin-1 receptor-induced PGE(2) production controls acetylcholine-mediated cardiac dysfunction and mortality during scorpion envenomation.
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: "we introduce a novel pathway that is targeted by dexamethasone, but not by anti-scorpion venom serum"
    explanation: >-
      What makes the two hypotheses prescribe differently rather than being
      two descriptions of one thing.
pathophysiology:
- name: Scorpion Venom Neurotoxin Binding to Voltage-Gated Sodium Channels
  biological_scale: MOLECULAR
  description: >-
    Buthid venom carries small peptide neurotoxins that bind the voltage-sensing
    domains of voltage-gated sodium channels. The alpha-toxins are the
    structurally resolved case: AaH2 from Androctonus australis wedges into
    voltage-sensing domain IV and traps it in a deactivated state, so the S4
    helix cannot make the translation that normally unlatches the fast
    inactivation gate. The modifier on the channel activity is
    `GAIN_OF_FUNCTION` rather than `INCREASED` deliberately: the claim is not
    that sodium current is quantitatively larger but that the channel has been
    taken outside its own regulatory constraint, since the gate that terminates
    its opening no longer operates. There is no host variant anywhere in this,
    so there is nothing for `functional_impact_category` to describe - the
    gain of function is imposed on a normal channel by a bound peptide.
  molecular_functions:
  - preferred_term: voltage-gated sodium channel activity, with fast inactivation disabled
    term:
      id: GO:0005248
      label: voltage-gated sodium channel activity
    modifier: GAIN_OF_FUNCTION
  downstream:
  - target: Failure of Sodium Channel Fast Inactivation and Repetitive Firing
    causal_link_type: DIRECT
    description: >-
      Trapping VSD4 in its deactivated state is the same event as preventing
      fast inactivation - the structure shows the mechanical linkage directly.
    evidence:
    - reference: PMID:30733386
      reference_title: Structural basis of α-scorpion toxin action on Na(v) channels.
      supports: SUPPORT
      evidence_source: IN_VITRO
      snippet: "In the absence of AaH2, the S4 helix of VSD4 undergoes a ~13-angstrom translation to unlatch the intracellular fast-inactivation gating machinery."
      explanation: >-
        Names the movement the toxin prevents, which is what connects toxin
        binding to the loss of inactivation in the next node.
  - target: Local paresthesia at bite site
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    description: >-
      The immediate local pain is attributed to the venom arriving in the
      tissue, and it is the earliest sign of envenomation. Marked
      INDIRECT_UNKNOWN_INTERMEDIATES rather than DIRECT on purpose: the source
      links the pain to venom penetration without naming the receptor or the
      afferent population it acts on, so the steps between this node and the
      symptom are not established here. The obvious candidate - the same
      sodium-channel action on peripheral nociceptors - is not what the cited
      sentence says.
    evidence:
    - reference: PMID:22826633
      reference_title: Emerging options for the management of scorpion stings.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      quote_role: REVIEW_SYNTHESIS
      snippet: "The first symptom of scorpion envenoming is localized pain, which reflects the penetration of the venom and is a valuable warning signal, especially in children."
      explanation: >-
        Attributes the local pain to the venom reaching the tissue and places
        it first in the sequence, which is the edge asserted here.
  evidence:
  - reference: PMID:30733386
    reference_title: Structural basis of α-scorpion toxin action on Na(v) channels.
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: "AaH2 wedges into voltage-sensing domain IV (VSD4) to impede fast activation by trapping a deactivated state"
    explanation: >-
      The binding event this node records, at 3.5-angstrom resolution in a
      toxin-channel complex.
- name: Failure of Sodium Channel Fast Inactivation and Repetitive Firing
  biological_scale: CELLULAR
  description: >-
    Channels that cannot inactivate leave the membrane depolarized and firing
    repetitively. Because sodium-channel fast inactivation is what terminates
    every action potential, disabling it converts a single stimulus into a
    train - the cellular event underlying the whole syndrome.
  biological_processes:
  - preferred_term: membrane depolarization during action potential
    term:
      id: GO:0086010
      label: membrane depolarization during action potential
    modifier: INCREASED
  cell_types:
  - preferred_term: sympathetic postganglionic neuron
    term:
      id: CL:0011103
      label: sympathetic neuron
  downstream:
  - target: Autonomic Neurotransmitter Storm
    causal_link_type: DIRECT
    description: >-
      Repetitive firing at autonomic terminals is what empties them.
    evidence:
    - reference: PMID:33116136
      reference_title: Interleukin-1 receptor-induced PGE(2) production controls acetylcholine-mediated cardiac dysfunction and mortality during scorpion envenomation.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      quote_role: BACKGROUND
      snippet: "toxins present in TsV activate ion channels that induce a neuroexcitatory syndrome known as a neurotransmitter storm"
      explanation: >-
        States the channel-to-storm step. Graded HUMAN_CLINICAL with
        quote_role BACKGROUND because the sentence is this mouse paper's
        introduction restating the established human syndrome, not its own
        result.
  evidence:
  - reference: PMID:30733386
    reference_title: Structural basis of α-scorpion toxin action on Na(v) channels.
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: "Fast inactivation of voltage-gated sodium (Nav) channels is essential for electrical signaling"
    explanation: >-
      Why disabling inactivation is not a subtle perturbation: it removes the
      mechanism that ends each action potential.
- name: Autonomic Neurotransmitter Storm
  biological_scale: ORGANISM
  description: >-
    Both divisions of the autonomic nervous system discharge at once. Sympathetic
    terminals and the adrenal medulla release catecholamines while parasympathetic
    terminals release acetylcholine, so the clinical picture is not a coherent
    adrenergic or cholinergic syndrome but both superimposed - tachycardia with
    hypersalivation, hypertension with vomiting, sweating with bradycardia.
  biological_processes:
  - preferred_term: catecholamine secretion
    term:
      id: GO:0050432
      label: catecholamine secretion
    modifier: INCREASED
  - preferred_term: acetylcholine secretion
    term:
      id: GO:0061526
      label: acetylcholine secretion
    modifier: INCREASED
  cell_types:
  - preferred_term: adrenal medulla chromaffin cell
    term:
      id: CL:0000336
      label: adrenal medulla chromaffin cell
  downstream:
  - target: Catecholamine-Mediated Myocardial Injury
    causal_link_type: DIRECT
    hypothesis_groups:
    - adrenergic_catecholamine_storm
    description: >-
      The adrenergic arm, and the one the canonical account holds responsible.
  - target: Fasciculations
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:32899951
      reference_title: "Autopsy Findings in Case of Fatal Scorpion Sting: A Systematic Review of the Literature."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      quote_role: REVIEW_SYNTHESIS
      snippet: "Edema, erythema, paresthesia, muscle fasciculations and numbness may occur at the site of the sting"
      explanation: >-
        Places muscle fasciculation among the direct neuroexcitatory effects.
        Note this sentence describes the sting site, where the entry's
        fasciculation phenotype is not site-restricted - it is cited for the
        mechanism, with the systemic distribution carried by the phenotype's
        own PMID:34055554 evidence.
  - target: Tremor
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:32899951
      reference_title: "Autopsy Findings in Case of Fatal Scorpion Sting: A Systematic Review of the Literature."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      quote_role: REVIEW_SYNTHESIS
      snippet: "neuromuscular (mydriasis, tremor, agitation, convulsions) complications"
      explanation: >-
        Tremor listed as a neuromuscular complication of the autonomic storm
        this node names, in the same sentence that enumerates the
        cardiovascular and metabolic arms already curated here.
  - target: Acute pancreatitis
    causal_link_type: INDIRECT_UNKNOWN_INTERMEDIATES
    description: >-
      Drawn as an indirect edge with unknown intermediates on purpose. The
      human study establishes pancreatic injury after envenomation and
      proposes no route to it; the murine IL-1 receptor and nitric-oxide work
      concerns islet function rather than acinar damage, so nothing in the
      entry's sources identifies what connects the storm to the pancreas.
    evidence:
    - reference: PMID:2028471
      reference_title: Acute pancreatitis in children following envenomation by the yellow scorpion Leiurus quinquestriatus.
      supports: SUPPORT
      directness: INDIRECT
      evidence_source: HUMAN_CLINICAL
      quote_role: PRIMARY_RESULT
      snippet: "The pancreatitis may account for the abdominal pain and vomiting commonly seen in scorpion envenomation"
      explanation: >-
        The authors' own proposal that the pancreatic injury explains two
        manifestations otherwise read as autonomic. INDIRECT because it is an
        inference the paper offers rather than a result it measures.
  - target: Hyperglycemia
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:33116136
      reference_title: Interleukin-1 receptor-induced PGE(2) production controls acetylcholine-mediated cardiac dysfunction and mortality during scorpion envenomation.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      quote_role: BACKGROUND
      snippet: "The excessive release of ACh is responsible for bradycardia, cardiac arrhythmias, elevated nasal, salivary, lachrymal, pancreatic, and bronchial secretions, along with piloerection and muscle spasms, while exaggerated catecholamine production mediates cardiac arrhythmias, tachycardia, arterial hypertension, shock, hyperglycemia, and leukocytosis"
      explanation: >-
        Names hyperglycaemia among the catecholamine-mediated manifestations.
  - target: Hyperhidrosis
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:37902581
      reference_title: "Moderate or severe scorpion sting: identification of risk factors."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      quote_role: BACKGROUND
      snippet: "profuse and uncontrollable vomiting, profuse sweating, intense sialorrhea, prostration, seizures, coma, bradycardia, heart failure, severe pulmonary edema and shock"
      explanation: >-
        Names profuse sweating among the features defining the severe grade. The
        earlier PMID:33116136 quote was withdrawn from this edge: it lists
        nasal, salivary, lachrymal, pancreatic and bronchial secretions and
        does not name sweat.
  - target: Excessive salivation
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:33116136
      reference_title: Interleukin-1 receptor-induced PGE(2) production controls acetylcholine-mediated cardiac dysfunction and mortality during scorpion envenomation.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      quote_role: BACKGROUND
      snippet: "The excessive release of ACh is responsible for bradycardia, cardiac arrhythmias, elevated nasal, salivary, lachrymal, pancreatic, and bronchial secretions, along with piloerection and muscle spasms, while exaggerated catecholamine production mediates cardiac arrhythmias, tachycardia, arterial hypertension, shock, hyperglycemia, and leukocytosis"
      explanation: >-
        Names salivary secretion among the acetylcholine-mediated manifestations.
  - target: Vomiting
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:37902581
      reference_title: "Moderate or severe scorpion sting: identification of risk factors."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      quote_role: BACKGROUND
      snippet: "profuse and uncontrollable vomiting, profuse sweating, intense sialorrhea, prostration, seizures, coma, bradycardia, heart failure, severe pulmonary edema and shock"
      explanation: >-
        Names uncontrollable vomiting among the features defining the severe
        grade. The PMID:33116136 transmitter list does not name vomiting, so it
        was withdrawn from this edge.
  - target: Priapism
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:21209062
      reference_title: "Efficacy and safety of scorpion antivenom plus prazosin compared with prazosin alone for venomous scorpion (Mesobuthus tamulus) sting: randomised open label clinical trial."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "priapism 4.7 (1.5) v 9.4 (1.5)"
      explanation: >-
        Priapism is tracked as an autonomic sign in both arms of this trial,
        which establishes it as a manifestation of the storm. The
        PMID:33116136 transmitter list does not name it and was withdrawn.
  - target: Tachycardia
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:33116136
      reference_title: Interleukin-1 receptor-induced PGE(2) production controls acetylcholine-mediated cardiac dysfunction and mortality during scorpion envenomation.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      quote_role: BACKGROUND
      snippet: "The excessive release of ACh is responsible for bradycardia, cardiac arrhythmias, elevated nasal, salivary, lachrymal, pancreatic, and bronchial secretions, along with piloerection and muscle spasms, while exaggerated catecholamine production mediates cardiac arrhythmias, tachycardia, arterial hypertension, shock, hyperglycemia, and leukocytosis"
      explanation: >-
        Names tachycardia among the catecholamine-mediated manifestations.
  - target: Bradycardia
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:33116136
      reference_title: Interleukin-1 receptor-induced PGE(2) production controls acetylcholine-mediated cardiac dysfunction and mortality during scorpion envenomation.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      quote_role: BACKGROUND
      snippet: "The excessive release of ACh is responsible for bradycardia, cardiac arrhythmias, elevated nasal, salivary, lachrymal, pancreatic, and bronchial secretions, along with piloerection and muscle spasms, while exaggerated catecholamine production mediates cardiac arrhythmias, tachycardia, arterial hypertension, shock, hyperglycemia, and leukocytosis"
      explanation: >-
        Names bradycardia as the acetylcholine-mediated one, which is why the entry carries both rate abnormalities.
  - target: Hypertension
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:33116136
      reference_title: Interleukin-1 receptor-induced PGE(2) production controls acetylcholine-mediated cardiac dysfunction and mortality during scorpion envenomation.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      quote_role: BACKGROUND
      snippet: "The excessive release of ACh is responsible for bradycardia, cardiac arrhythmias, elevated nasal, salivary, lachrymal, pancreatic, and bronchial secretions, along with piloerection and muscle spasms, while exaggerated catecholamine production mediates cardiac arrhythmias, tachycardia, arterial hypertension, shock, hyperglycemia, and leukocytosis"
      explanation: >-
        Names arterial hypertension among the catecholamine-mediated manifestations.
  evidence:
  - reference: PMID:33116136
    reference_title: Interleukin-1 receptor-induced PGE(2) production controls acetylcholine-mediated cardiac dysfunction and mortality during scorpion envenomation.
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: "We detected a dramatic increase in the concentration of adrenaline and ACh compared to PBS-inoculated mice"
    explanation: >-
      Measures both arms of the storm simultaneously in plasma, which is the
      claim this node makes - not that one or other transmitter rises.
  - reference: PMID:34055554
    reference_title: Neurological and Systemic Manifestations of Severe Scorpion Envenomation.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    snippet: "The toxin released by the sting stimulates the autonomic nervous system (ANS), sympathetic and parasympathetic, which activates the coagulation cascade."
    explanation: The same dual activation stated for the human disease.
- name: Catecholamine-Mediated Myocardial Injury
  biological_scale: TISSUE
  description: >-
    Sustained adrenergic stimulation injures the myocardium by three routes that
    the literature has not fully separated: a direct adrenergic myocarditis, a
    toxic myocarditis attributed to venom itself, and myocardial ischaemia driven
    by raised oxygen demand together with cytokine and neuropeptide Y effects on
    the coronary vessels.
  cell_types:
  - preferred_term: cardiac muscle cell
    term:
      id: CL:0000746
      label: cardiac muscle cell
  locations:
  - preferred_term: heart
    term:
      id: UBERON:0000948
      label: heart
  downstream:
  - target: Cardiac Dysfunction and Pulmonary Edema
    causal_link_type: DIRECT
    hypothesis_groups:
    - adrenergic_catecholamine_storm
    evidence:
    - reference: PMID:15687982
      reference_title: "[Cardiovascular dysfunction following severe scorpion envenomation. Mechanisms and physiopathology]."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      quote_role: REVIEW_SYNTHESIS
      snippet: "The seriousness of scorpion envenomation results essentially from left cardiac function with pulmonary oedema and/or a state of shock."
      explanation: States the step from myocardial injury to the clinical failure syndrome.
  - target: Myocarditis
    causal_link_type: DIRECT
  evidence:
  - reference: PMID:15687982
    reference_title: "[Cardiovascular dysfunction following severe scorpion envenomation. Mechanisms and physiopathology]."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    snippet: "Adrenergic myocarditis, toxic myocarditis and myocardial ischemia are the 3 mechanisms that explain the cardiac dysfunction."
    explanation: >-
      The three convergent routes this node bundles, named as three rather
      than resolved into one - which is the state of the evidence.
- name: Venom-Triggered Cardiac IL-1R Signaling and PGE2 Production
  biological_scale: CELLULAR
  conforms_to: nlrp3_inflammasome_activation#NLRP3 Inflammasome Assembly and Caspase-1 Activation
  description: >-
    Venom reaching the heart is sensed as a danger signal. Cardiac fibroblasts
    and resident macrophages produce IL-1 beta through an NLRP3-, ASC- and
    caspase-1-dependent route and prostaglandin E2 alongside it, and IL-1
    receptor signalling is required to sustain the PGE2 output. This node is the
    entry point of the emerging hypothesis arm and is demonstrated only in mice.
  biological_processes:
  - preferred_term: prostaglandin E2 biosynthesis in the envenomed heart
    term:
      id: GO:0001516
      label: prostaglandin biosynthetic process
    modifier: INCREASED
  cell_types:
  - preferred_term: cardiac fibroblast
    term:
      id: CL:0002548
      label: fibroblast of cardiac tissue
  downstream:
  - target: Excessive Vagal Acetylcholine Release at the Heart
    causal_link_type: DIRECT
    hypothesis_groups:
    - il1r_pge2_cholinergic_axis
    evidence:
    - reference: PMID:33116136
      reference_title: Interleukin-1 receptor-induced PGE(2) production controls acetylcholine-mediated cardiac dysfunction and mortality during scorpion envenomation.
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      snippet: "PGE2 signaling via EP2/4 receptors mediates excessive ACh release, which in turn causes the heart failure of envenomed mice"
      explanation: >-
        Names the receptor through which this edge operates and the outcome it
        produces, in the model organism where it was shown.
  evidence:
  - reference: PMID:33116136
    reference_title: Interleukin-1 receptor-induced PGE(2) production controls acetylcholine-mediated cardiac dysfunction and mortality during scorpion envenomation.
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: "TsV increased NLRP3, Asc, and Casp1/11−dependent IL-1β release"
    explanation: >-
      The inflammasome dependency that grounds this node's conformance to the
      NLRP3 module. The three gene names qualify "dependent IL-1 beta release":
      the claim is that release required NLRP3, ASC and caspase-1, which is
      assembly-and-activation evidence rather than transcript upregulation. The
      character between "11" and "dependent" is U+2212 MINUS SIGN as the source
      renders it, not a hyphen.
- name: Excessive Vagal Acetylcholine Release at the Heart
  biological_scale: ORGANISM
  description: >-
    The cholinergic arm of the emerging account. Parasympathetic output to the
    heart is driven beyond the range the organ tolerates, producing the
    bradycardia and arrhythmia of the syndrome and, in mice, the fatal cardiac
    dysfunction itself.
  biological_processes:
  - preferred_term: acetylcholine secretion
    term:
      id: GO:0061526
      label: acetylcholine secretion
    modifier: INCREASED
  evidence:
  - reference: PMID:33116136
    reference_title: Interleukin-1 receptor-induced PGE(2) production controls acetylcholine-mediated cardiac dysfunction and mortality during scorpion envenomation.
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: "PGE2 signaling via EP2/4 receptors mediates excessive ACh release, which in turn causes the heart failure of envenomed mice"
    explanation: >-
      Establishes this node directly - that acetylcholine release is driven to
      excess and that it is what produces the heart failure. The haemodynamic
      measurement is cited on the animal model instead, where it sits before
      the mechanism is established and so cannot carry it.
  downstream:
  - target: Cardiac Dysfunction and Pulmonary Edema
    causal_link_type: DIRECT
    hypothesis_groups:
    - il1r_pge2_cholinergic_axis
    description: >-
      The claim that distinguishes this hypothesis from the canonical one: the
      heart failure is cholinergic in origin.
    evidence:
    - reference: PMID:33116136
      reference_title: Interleukin-1 receptor-induced PGE(2) production controls acetylcholine-mediated cardiac dysfunction and mortality during scorpion envenomation.
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      snippet: "IL-1R deficiency, the treatment with a high dose of dexamethasone or blockage of parasympathetic signaling using atropine or vagotomy, abolished heart failure and mortality of envenomed mice."
      explanation: >-
        Four independent interventions at three different points of this arm
        each abolish the outcome, which is what makes the edge causal rather
        than correlative in the model.
- name: Cardiac Dysfunction and Pulmonary Edema
  biological_scale: ORGANISM
  description: >-
    The convergence point of both hypothesis arms and the proximate cause of
    almost every scorpion-sting death. Left ventricular failure with pulmonary
    oedema develops within hours, is far commoner in children, and is reversible
    in survivors - left ventricular function recovers in almost all who live.
  locations:
  - preferred_term: lung
    term:
      id: UBERON:0002048
      label: lung
  downstream:
  - target: Pulmonary edema
    causal_link_type: DIRECT
  - target: Hypotension
    causal_link_type: DIRECT
  evidence:
  - reference: PMID:33116136
    reference_title: Interleukin-1 receptor-induced PGE(2) production controls acetylcholine-mediated cardiac dysfunction and mortality during scorpion envenomation.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: BACKGROUND
    snippet: "Major clinical manifestations that precede death after scorpion envenomation include heart failure and pulmonary edema."
    explanation: >-
      Identifies this node as the terminal one. BACKGROUND because it is the
      mouse paper's framing of the human disease rather than its own finding.
  - reference: PMID:34055554
    reference_title: Neurological and Systemic Manifestations of Severe Scorpion Envenomation.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    snippet: "Scorpion envenomation is especially fatal in the first hours, usually due to respiratory and/or cardiovascular collapse."
    explanation: The timing and the mode of death this node produces.
  - reference: PMID:37018229
    reference_title: "Scorpion envenomation-associated myocarditis: A systematic review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Almost all survived cases showed rapid recovery and improvement in the left ventricular function."
    explanation: >-
      The reversibility that makes supportive care worth escalating: the
      myocardial failure is not structural damage.
  - reference: PMID:32899951
    reference_title: "Autopsy Findings in Case of Fatal Scorpion Sting: A Systematic Review of the Literature."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    snippet: "When the sting is fatal, the mechanism of death is often related to cardiotoxicity with terminal pulmonary edema."
    explanation: >-
      A systematic review of post-mortem findings reaching this node as the
      usual mechanism of death - the strongest form the claim can take, since
      it rests on autopsies rather than on clinical impression.
  - reference: PMID:32899951
    reference_title: "Autopsy Findings in Case of Fatal Scorpion Sting: A Systematic Review of the Literature."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    snippet: "However, the cholinergic excess or the neuromuscular excitation can provoke respiratory failure."
    explanation: >-
      Recorded because it names a cholinergic route to death in human autopsy
      material, independently of the mouse work behind the emerging
      hypothesis. It is not evidence for the IL-1R pathway - it says nothing
      about how the cholinergic excess arises - but it is the reason the
      cholinergic arm cannot be dismissed as a mouse artefact.
- name: Cytolytic Venom Membrane Damage
  biological_scale: MOLECULAR
  description: >-
    The Hemiscorpius lepturus branch, and the point at which this subtype leaves
    the rest of the entry. The venom is cytolytic rather than neurotoxic, lysing
    cell membranes at the sting site and in the circulation. The sting itself is
    characteristically not painful, which is why presentation is late.
  notes: >-
    Named for the effect rather than the enzyme. The literature attributes the
    cytolysis to a lysophospholipase D and related lytic enzymes, but no source
    cited in this entry says so and the node carries no `molecular_functions`
    binding to hold the claim, so naming it for a phospholipase would have
    asserted an enzymology the entry does not evidence.
  downstream:
  - target: Intravascular Hemolysis with Acquired ADAMTS13 Deficiency
    causal_link_type: DIRECT
  - target: Skin ulcer
    causal_link_type: DIRECT
  evidence:
  - reference: PMID:9679690
    reference_title: "Cutaneous manifestations of the Hemiscorpius lepturus sting: a clinical study."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "HL venom is cytotoxic, and HL is the only scorpion whose venom induces a toxic reaction."
    explanation: The venom property this branch turns on.
- name: Intravascular Hemolysis with Acquired ADAMTS13 Deficiency
  biological_scale: ORGANISM
  description: >-
    Haemolysis is followed by a fall in ADAMTS13 together with an anti-ADAMTS13
    IgG in almost every severe case - an acquired, antibody-mediated deficiency
    of the von Willebrand factor-cleaving protease rather than consumption
    alone. The deficiency tracks the renal outcome exactly: every child with
    acute kidney injury had it, and no child with normal ADAMTS13 developed
    renal failure.
  downstream:
  - target: Thrombotic Microangiopathy and Acute Kidney Injury
    causal_link_type: DIRECT
    evidence:
    - reference: PMID:23893367
      reference_title: High frequency of acquired ADAMTS13 deficiency after hemolysis in Hemiscorpius Lepturus (scorpion) stung children.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "ADAMTS13 decreased in all of the patients with acute kidney injury and none of those with normal levels of ADAMTS13 developed renal failure"
      explanation: >-
        A complete separation between the two groups, which is about as strong
        as an observational series can make a causal edge.
  evidence:
  - reference: PMID:23893367
    reference_title: High frequency of acquired ADAMTS13 deficiency after hemolysis in Hemiscorpius Lepturus (scorpion) stung children.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "ADAMTS13 was decreased in 91.7 % of patients and the anti-ADAMTS13 antibody (Ab) was increased in 98.3 %."
    explanation: >-
      The node's actual claim, quantified: the protease falls and the
      autoantibody rises in almost every severe case, which is what makes this
      an acquired antibody-mediated deficiency rather than consumption alone.
  - reference: PMID:23893367
    reference_title: High frequency of acquired ADAMTS13 deficiency after hemolysis in Hemiscorpius Lepturus (scorpion) stung children.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Sixty scorpion stung children who were referred with severe hemolysis and hemoglobinuria were studied."
    explanation: The cohort and the presenting haemolysis this node records.
- name: Thrombotic Microangiopathy and Acute Kidney Injury
  biological_scale: ORGANISM
  description: >-
    The terminal node of the cytotoxic branch: disseminated intravascular
    coagulation and haemolytic uraemic syndrome, with acute kidney injury in
    about a quarter of severe cases.
  locations:
  - preferred_term: kidney
    term:
      id: UBERON:0002113
      label: kidney
  downstream:
  - target: Acute kidney injury
    causal_link_type: DIRECT
  - target: Hemolytic-uremic syndrome
    causal_link_type: DIRECT
  - target: Thrombocytopenia
    causal_link_type: DIRECT
  evidence:
  - reference: PMID:23893367
    reference_title: High frequency of acquired ADAMTS13 deficiency after hemolysis in Hemiscorpius Lepturus (scorpion) stung children.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Acute kidney injury was found in 23.3 % and had significant association with severe anemia, thrombocytopenia, pyuria, hematuria and considerable proteinuria"
    explanation: The haematological and renal findings that define this node.
phenotypes:
- category: Neurologic
  name: Local paresthesia at bite site
  description: >-
    Severe pain and paraesthesia at the sting site, immediate and out of
    proportion to anything visible. In buthid stings there is characteristically
    no local reaction to see, which is itself diagnostic.
  phenotype_term:
    preferred_term: Local paresthesia at sting site
    term:
      id: HP:0020014
      label: Local paresthesia at bite site
    temporality: ACUTE
  subtype: Neurotoxic
  notes: >-
    HPO's term is worded for a bite; the sting is the same clinical entity and
    HPO carries no sting-specific counterpart. `runoak`/OLS `q=sting,
    ontology=hp` returns only `HP:6000420` Burning eye sensation and a CHEBI
    formic-acid hit, and `q=envenomation, ontology=hp` returns nothing, so the
    specificity is carried in `preferred_term`.
  evidence:
  - reference: PMID:37902581
    reference_title: "Moderate or severe scorpion sting: identification of risk factors."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: BACKGROUND
    snippet: "the accident is considered mild if it only presents local pain, with or without paresthesia; moderate, if there is severe local pain and systemic manifestations (slight sweating, nausea, occasional vomiting, tachycardia, tachypnea, and hypertension)"
    explanation: >-
      Places local pain with or without paraesthesia as the defining feature of the mild grade, that is, the floor of the clinical spectrum.
- category: Cardiovascular
  name: Tachycardia
  phenotype_term:
    preferred_term: Tachycardia
    term:
      id: HP:0001649
      label: Tachycardia
  subtype: Neurotoxic
  description: The adrenergic arm of the storm, and the commonest ECG finding.
  evidence:
  - reference: PMID:37018229
    reference_title: "Scorpion envenomation-associated myocarditis: A systematic review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The most common ECG findings are sinus tachycardia (82%) followed by ST-T changes (64.6%)."
    explanation: Frequency in the 703-case myocarditis series.
- category: Cardiovascular
  name: Bradycardia
  phenotype_term:
    preferred_term: Bradycardia
    term:
      id: HP:0001662
      label: Bradycardia
  subtype: Neurotoxic
  description: >-
    The cholinergic arm. Recorded separately from tachycardia rather than as a
    single rate abnormality because the two occur in the same patient at
    different times and are attributed to opposite transmitters.
  evidence:
  - reference: PMID:37902581
    reference_title: "Moderate or severe scorpion sting: identification of risk factors."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: BACKGROUND
    snippet: "profuse and uncontrollable vomiting, profuse sweating, intense sialorrhea, prostration, seizures, coma, bradycardia, heart failure, severe pulmonary edema and shock"
    explanation: >-
      Lists bradycardia among the features defining the severe grade.
- category: Cardiovascular
  name: Hypertension
  phenotype_term:
    preferred_term: Hypertension
    term:
      id: HP:0000822
      label: Hypertension
  subtype: Neurotoxic
  evidence:
  - reference: PMID:37902581
    reference_title: "Moderate or severe scorpion sting: identification of risk factors."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: BACKGROUND
    snippet: "the accident is considered mild if it only presents local pain, with or without paresthesia; moderate, if there is severe local pain and systemic manifestations (slight sweating, nausea, occasional vomiting, tachycardia, tachypnea, and hypertension)"
    explanation: >-
      Lists hypertension among the systemic manifestations defining the moderate grade.
- category: Cardiovascular
  name: Hypotension
  phenotype_term:
    preferred_term: Hypotension
    term:
      id: HP:0002615
      label: Hypotension
  subtype: Neurotoxic
  description: Shock, in the later phase and in the severe cases.
  evidence:
  - reference: PMID:37018229
    reference_title: "Scorpion envenomation-associated myocarditis: A systematic review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Myocarditis associated with scorpion envenomation was usually reported in children presenting with cardiopulmonary symptoms including pulmonary edema (60.7%) and shock or hypotension (45.8%)."
    explanation: Frequency of shock among the myocarditis cases, and its co-occurrence with pulmonary oedema.
- category: Respiratory
  name: Pulmonary edema
  phenotype_term:
    preferred_term: Pulmonary edema
    term:
      id: HP:0100598
      label: Pulmonary edema
    temporality: ACUTE
  subtype: Neurotoxic
  description: The dominant proximate cause of death.
  evidence:
  - reference: PMID:37018229
    reference_title: "Scorpion envenomation-associated myocarditis: A systematic review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Myocarditis associated with scorpion envenomation was usually reported in children presenting with cardiopulmonary symptoms including pulmonary edema (60.7%) and shock or hypotension (45.8%)."
    explanation: Frequency in the same series.
- category: Cardiovascular
  name: Myocarditis
  phenotype_term:
    preferred_term: Myocarditis
    term:
      id: HP:0012819
      label: Myocarditis
  subtype: Neurotoxic
  evidence:
  - reference: PMID:37018229
    reference_title: "Scorpion envenomation-associated myocarditis: A systematic review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Mortality in confirmed scorpion-related myocarditis cases is estimated at 7.3%."
    explanation: >-
      The case fatality once myocarditis is established, which is what makes
      this phenotype the one that matters prognostically.
- category: Constitutional
  name: Hyperhidrosis
  phenotype_term:
    preferred_term: Hyperhidrosis
    term:
      id: HP:0000975
      label: Hyperhidrosis
  subtype: Neurotoxic
  evidence:
  - reference: PMID:37902581
    reference_title: "Moderate or severe scorpion sting: identification of risk factors."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: BACKGROUND
    snippet: "the accident is considered mild if it only presents local pain, with or without paresthesia; moderate, if there is severe local pain and systemic manifestations (slight sweating, nausea, occasional vomiting, tachycardia, tachypnea, and hypertension)"
    explanation: >-
      Sweating appears at the moderate grade and becomes profuse at the severe one, in the same national grading scheme.
- category: Gastrointestinal
  name: Excessive salivation
  phenotype_term:
    preferred_term: Excessive salivation
    term:
      id: HP:0003781
      label: Excessive salivation
  subtype: Neurotoxic
  description: >-
    Part of the cholinergic secretory picture, alongside lacrimation and
    bronchial secretion.
  evidence:
  - reference: PMID:37902581
    reference_title: "Moderate or severe scorpion sting: identification of risk factors."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: BACKGROUND
    snippet: "profuse and uncontrollable vomiting, profuse sweating, intense sialorrhea, prostration, seizures, coma, bradycardia, heart failure, severe pulmonary edema and shock"
    explanation: >-
      Lists intense sialorrhea among the features defining the severe grade.
- category: Gastrointestinal
  name: Vomiting
  phenotype_term:
    preferred_term: Vomiting
    term:
      id: HP:0002013
      label: Vomiting
  subtype: Neurotoxic
  evidence:
  - reference: PMID:37902581
    reference_title: "Moderate or severe scorpion sting: identification of risk factors."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: BACKGROUND
    snippet: "the accident is considered mild if it only presents local pain, with or without paresthesia; moderate, if there is severe local pain and systemic manifestations (slight sweating, nausea, occasional vomiting, tachycardia, tachypnea, and hypertension)"
    explanation: >-
      Vomiting appears at the moderate grade in this grading scheme and becomes uncontrollable at the severe one.
- category: Genitourinary
  name: Priapism
  phenotype_term:
    preferred_term: Priapism
    term:
      id: HP:0200023
      label: Priapism
  subtype: Neurotoxic
  description: >-
    An autonomic sign, and in endemic regions an unusually specific one in a
    child with an unwitnessed sting.
- category: Metabolic
  name: Hyperglycemia
  phenotype_term:
    preferred_term: Hyperglycemia
    term:
      id: HP:0003074
      label: Hyperglycemia
  subtype: Neurotoxic
  description: >-
    Counter-regulatory, and in mice shown to run through an IL-1 receptor and
    nitric oxide pathway in the pancreas rather than through catecholamines
    alone.
  evidence:
  - reference: PMID:32150895
    reference_title: Interleukin-1 Receptor-Induced Nitric Oxide Production in the Pancreas Controls Hyperglycemia Caused by Scorpion Envenomation.
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: "Il1r1-/- mice were protected from transitory hyperglycemia and did not present disturbances in insulin levels in the serum."
    explanation: >-
      An IL-1 receptor knockout abolishes the hyperglycaemia, which is what
      puts this phenotype on the inflammatory arm rather than purely on the
      catecholamine one.
  - reference: PMID:32150895
    reference_title: Interleukin-1 Receptor-Induced Nitric Oxide Production in the Pancreas Controls Hyperglycemia Caused by Scorpion Envenomation.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: BACKGROUND
    snippet: "Among these events, transitory hyperglycemia is a severe manifestation that influences pulmonary edema, hemodynamic alterations, and cardiac disturbances."
    explanation: >-
      Why the sign matters clinically rather than being an incidental
      laboratory finding. BACKGROUND: the mouse paper's framing, not its result.
- category: Neurologic
  name: Fasciculations
  phenotype_term:
    preferred_term: Fasciculations
    term:
      id: HP:0002380
      label: Fasciculations
  subtype: Neurotoxic
  description: >-
    Involuntary muscle twitching from the same repetitive firing that drives
    the autonomic discharge, at the neuromuscular junction rather than at the
    ganglia.
  evidence:
  - reference: PMID:34055554
    reference_title: Neurological and Systemic Manifestations of Severe Scorpion Envenomation.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    snippet: "Guillain-Barre-like syndrome, myelitis, abnormal eye movements, facial and eye paralysis, fasciculations, and muscle jerks simulating seizures have been reported."
    explanation: >-
      Names fasciculations among the reported neurological manifestations of
      severe envenomation.
- category: Neurologic
  name: Tremor
  phenotype_term:
    preferred_term: Tremor
    term:
      id: HP:0001337
      label: Tremor
  subtype: Neurotoxic
  description: >-
    Part of the neuromuscular component of the autonomic storm, alongside
    agitation and convulsions.
  evidence:
  - reference: PMID:32899951
    reference_title: "Autopsy Findings in Case of Fatal Scorpion Sting: A Systematic Review of the Literature."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    snippet: "This excessive release of neurotransmitters provokes an autonomic storm consisting of cardiovascular (tachycardia, peripheral vasoconstriction, hypertension, diaphoresis), metabolic (hyperthermia, hyperglycemia), urogenital (bladder dilatation, urinary retention, ejaculation in males), respiratory (bronchial dilation, tachypnea) and neuromuscular (mydriasis, tremor, agitation, convulsions) complications."
    explanation: >-
      Attributes tremor to the neurotransmitter release this entry calls the
      autonomic storm, which is the node it is wired from.
- category: Gastrointestinal
  name: Acute pancreatitis
  phenotype_term:
    preferred_term: Acute pancreatitis
    term:
      id: HP:0001735
      label: Acute pancreatitis
  subtype: Neurotoxic
  description: >-
    Common enough after a Leiurus quinquestriatus sting to be measurable in
    almost every envenomed child, and a plausible explanation for the abdominal
    pain and vomiting that would otherwise be read as autonomic alone. How the
    storm reaches the pancreas is not established: the human study measures the
    injury without proposing a route, and the only mechanistic work is the
    murine IL-1 receptor and nitric-oxide pathway curated behind
    `Hyperglycemia`, which concerns islet function rather than acinar injury.
  evidence:
  - reference: PMID:2028471
    reference_title: Acute pancreatitis in children following envenomation by the yellow scorpion Leiurus quinquestriatus.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: PRIMARY_RESULT
    snippet: "High ICT levels were found in 13 children (93%), indicating that acute pancreatitis is a common complication of envenomation by this scorpion."
    explanation: >-
      Immunoreactive cationic trypsin raised in 13 of 14 envenomed children,
      which is a biochemical measure of pancreatic injury rather than a
      clinical impression.
- category: Dermatologic
  name: Skin ulcer
  phenotype_term:
    preferred_term: Dermonecrosis and ulceration at the sting site
    term:
      id: HP:0200042
      label: Skin ulcer
  subtype: Cytotoxic
  description: >-
    Delayed local necrosis, seen only in the cytotoxic subtype and evolving over
    days through erythema, purpura and bullae.
  evidence:
  - reference: PMID:9679690
    reference_title: "Cutaneous manifestations of the Hemiscorpius lepturus sting: a clinical study."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Erythema, purpuric changes, bullae, necrosis, and ulcers, or a combination of these, may be seen at different stages."
    explanation: The staged local lesion this phenotype records.
- category: Renal
  name: Acute kidney injury
  phenotype_term:
    preferred_term: Acute kidney injury
    term:
      id: HP:0001919
      label: Acute kidney injury
  subtype: Cytotoxic
  evidence:
  - reference: PMID:23893367
    reference_title: High frequency of acquired ADAMTS13 deficiency after hemolysis in Hemiscorpius Lepturus (scorpion) stung children.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "ADAMTS13 decreased in all of the patients with acute kidney injury and none of those with normal levels of ADAMTS13 developed renal failure"
    explanation: >-
      Establishes the renal outcome in this cohort and its complete dependence on the ADAMTS13 fall.
- category: Hematologic
  name: Hemolytic-uremic syndrome
  phenotype_term:
    preferred_term: Hemolytic-uremic syndrome
    term:
      id: HP:0005575
      label: Hemolytic-uremic syndrome
  subtype: Cytotoxic
  evidence:
  - reference: PMID:23893367
    reference_title: High frequency of acquired ADAMTS13 deficiency after hemolysis in Hemiscorpius Lepturus (scorpion) stung children.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "all patients with AKI had also increased levels of ADAMTS13Ab"
    explanation: >-
      The antibody-mediated ADAMTS13 deficiency that underlies the microangiopathic picture this phenotype names.
- category: Hematologic
  name: Thrombocytopenia
  phenotype_term:
    preferred_term: Thrombocytopenia
    term:
      id: HP:0001873
      label: Thrombocytopenia
  subtype: Cytotoxic
  evidence:
  - reference: PMID:23893367
    reference_title: High frequency of acquired ADAMTS13 deficiency after hemolysis in Hemiscorpius Lepturus (scorpion) stung children.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Acute kidney injury was found in 23.3 % and had significant association with severe anemia, thrombocytopenia, pyuria, hematuria and considerable proteinuria"
    explanation: >-
      Names thrombocytopenia among the findings associated with the renal outcome in this series.
biochemical:
- name: N-terminal pro-B-type natriuretic peptide (NT-proBNP)
  presence: INCREASED
  subtype: Neurotoxic
  biomarker_term:
    preferred_term: N-terminal pro-B-type natriuretic peptide
    term:
      id: NCIT:C88524
      label: N-Terminal Fragment Brain Natriuretic Protein
  notes: >-
    The best-characterised marker here, and the one that answers the question
    that matters at triage: which of the children who arrive symptomatic are
    going to develop cardiac failure. It is a readout of ventricular wall
    stress, so it reports the downstream consequence of the storm rather than
    the venom or the storm itself.
  evidence:
  - reference: PMID:33094659
    reference_title: "Scorpion sting: N-terminal fragment of proB-type natriuretic peptide as an early predictor of pediatric cardiotoxicity."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: PRIMARY_RESULT
    snippet: "Assessment of NT-proBNP levels showed a significant increase in all moderate to severe cases on admission and 6 h post-envenomation."
    explanation: >-
      The elevation itself, in a prospective series of 483 stung children, and
      present already on admission rather than only at six hours.
  - reference: PMID:33094659
    reference_title: "Scorpion sting: N-terminal fragment of proB-type natriuretic peptide as an early predictor of pediatric cardiotoxicity."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: PRIMARY_RESULT
    snippet: "The sensitivity of NT-proBNP for the diagnosis of myocardial injury at hospital admission was significantly higher than that of CPK-MB."
    explanation: >-
      The head-to-head comparison against the other marker curated here, in the
      same patients and at the same time point.
  readouts:
  - target: Cardiac Dysfunction and Pulmonary Edema
    relationship: PREDICTS
    direction: POSITIVE
    endpoint_context: PROGNOSTIC
    interpretation: >-
      An admission NT-proBNP identifies the children who will develop
      cardiotoxicity, hours before echocardiography or the clinical picture
      does.
    evidence:
    - reference: PMID:33094659
      reference_title: "Scorpion sting: N-terminal fragment of proB-type natriuretic peptide as an early predictor of pediatric cardiotoxicity."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      quote_role: PRIMARY_RESULT
      snippet: "NT-proBNP may be a valuable and sensitive laboratory biomarker to predict cardiotoxicity of scorpion sting in the early hours."
      explanation: >-
        The authors' own statement of the prognostic claim this readout makes.
    - reference: PMID:33994108
      reference_title: The Role of ProBNP on Prognosis in Scorpion Stings.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      quote_role: PRIMARY_RESULT
      snippet: "ProBNP 1 was significantly higher in the severe group at admission (P=0.016)."
      explanation: >-
        A second, independent paediatric series reaching the same conclusion
        from the admission value, against a severity grading rather than
        against a cardiac endpoint.
  - target: Cardiac Dysfunction and Pulmonary Edema
    relationship: CORRELATES_WITH
    direction: NEGATIVE
    endpoint_context: DIAGNOSTIC
    interpretation: >-
      The level tracks inversely with measured ventricular performance, which
      is what makes it a readout of this node rather than a general severity
      marker.
    evidence:
    - reference: PMID:33994108
      reference_title: The Role of ProBNP on Prognosis in Scorpion Stings.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      quote_role: PRIMARY_RESULT
      snippet: "There was a negative correlation between proBNP and echocardiographic findings involving ejection fraction and shortening fraction (r=-0.703, P=0.002)."
      explanation: >-
        Ties the marker directly to ejection and shortening fraction, which is
        the node this readout points at. Direction is NEGATIVE because the
        quantity correlated is preserved function, not injury.
- name: Creatine kinase MB (CK-MB)
  presence: INCREASED
  subtype: Neurotoxic
  biomarker_term:
    preferred_term: creatine kinase MB
    term:
      id: NCIT:C122778
      label: Creatine Kinase MB
  notes: >-
    Curated alongside NT-proBNP rather than instead of it, because the two are
    not measuring the same thing: CK-MB reports myocyte injury and NT-proBNP
    reports wall stress. In this disease the injury marker is the later and
    less sensitive of the two.
  evidence:
  - reference: PMID:33094659
    reference_title: "Scorpion sting: N-terminal fragment of proB-type natriuretic peptide as an early predictor of pediatric cardiotoxicity."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: PRIMARY_RESULT
    snippet: "Assessment of CPK-MB levels showed a significant increase in all moderate to severe cases 6 h post-envenomation."
    explanation: >-
      The elevation, and its timing - six hours, where NT-proBNP was already
      raised on admission in the same cohort.
  readouts:
  - target: Catecholamine-Mediated Myocardial Injury
    relationship: READOUT_OF
    direction: POSITIVE
    endpoint_context: DIAGNOSTIC
    interpretation: >-
      CK-MB release reports myocardial cell injury, which is the lesion this
      node asserts, rather than the ventricular failure it produces.
    evidence:
    - reference: PMID:33094659
      reference_title: "Scorpion sting: N-terminal fragment of proB-type natriuretic peptide as an early predictor of pediatric cardiotoxicity."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      quote_role: PRIMARY_RESULT
      snippet: "Assessment of CPK-MB levels showed a significant increase in all moderate to severe cases 6 h post-envenomation."
      explanation: >-
        The measurement is of a cardiac-specific enzyme in circulation, so it
        reports myocyte membrane injury at this node.
- name: Cardiac troponin
  presence: INCREASED
  subtype: Neurotoxic
  biomarker_term:
    preferred_term: cardiac troponin I
    term:
      id: NCIT:C17343
      label: Troponin I
  notes: >-
    The one marker here where the evidence is split, and the split appears to
    be an assay effect rather than a disagreement about the biology: a
    conventional troponin I did not separate severity groups, while an
    ultrasensitive assay against an echocardiographic endpoint performed better
    than either new marker tested beside it. Both results are recorded.
  evidence:
  - reference: PMID:39842516
    reference_title: New biomarkers in scorpion stings.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: PRIMARY_RESULT
    snippet: "Ultrasensitive troponin presented an AUC of 0.89, with a sensitivity of 84.6%."
    explanation: >-
      The ultrasensitive assay against echocardiographically confirmed left
      ventricular dysfunction, and the best discrimination reported in that
      study.
  - reference: PMID:33994108
    reference_title: The Role of ProBNP on Prognosis in Scorpion Stings.
    supports: REFUTE
    evidence_source: HUMAN_CLINICAL
    quote_role: PRIMARY_RESULT
    snippet: "There was no difference between the troponin I values (P=0.051)."
    explanation: >-
      A null result for conventional troponin I, in the same patients and at
      the same time point where proBNP did separate the groups. REFUTE against
      the claim that troponin is informative here, recorded rather than
      dropped - the two studies used different assays and different endpoints,
      which is the most likely reason they disagree.
  readouts:
  - target: Cardiac Dysfunction and Pulmonary Edema
    relationship: READOUT_OF
    direction: POSITIVE
    endpoint_context: DIAGNOSTIC
    interpretation: >-
      With a high-sensitivity assay, circulating troponin detects the
      ventricular dysfunction this node describes. Read together with the
      null conventional-assay result recorded above.
    evidence:
    - reference: PMID:39842516
      reference_title: New biomarkers in scorpion stings.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      quote_role: PRIMARY_RESULT
      snippet: "Ultrasensitive troponin presented an AUC of 0.89, with a sensitivity of 84.6%."
      explanation: >-
        Discrimination against cardiac dysfunction identified by cardiac
        ultrasound, which is this node.
- name: Soluble ST2 (sST2)
  presence: INCREASED
  subtype: Neurotoxic
  biomarker_term:
    preferred_term: soluble ST2 (sST2)
    term:
      id: NCIT:C106011
      label: Interleukin-1 Receptor-Like 1
  notes: >-
    Bound to the parent protein because NCIT has no term for the soluble
    isoform. OLS `q=Soluble ST2, ontology=ncit` returns nothing at all;
    `q=ST2, ontology=ncit` returns `NCIT:C105385` ST2 Gene, `NCIT:C106009`
    IL1RL1 wt Allele, `NCIT:C192871` IL1RL1 Positive, `NCIT:C187445` ST2
    Diffuse Large B-Cell Lymphoma and `NCIT:C171824` Astegolimab, none of
    which is the circulating decoy receptor; `q=Interleukin 1 Receptor Like 1,
    ontology=ncit` returns the protein `NCIT:C106011` and the measurement
    `NCIT:C142281`. The isoform identity is carried in `preferred_term`.
    Worth noting that ST2 is an IL-1 family receptor, so a marker of the
    inflammatory arm is doing diagnostic work here whichever hypothesis turns
    out to be right - but the study measures it as a cardiac-dysfunction
    marker and makes no claim about the IL-1R pathway.
  evidence:
  - reference: PMID:39842516
    reference_title: New biomarkers in scorpion stings.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: PRIMARY_RESULT
    snippet: "The biomarkers of sST2 and FABP-3 showed an association with left ventricular dysfunction, presenting AUCs of 0.77 and 0.81, respectively."
    explanation: >-
      The result establishing sST2 as a candidate marker in this disease, with
      its discrimination quantified.
  readouts:
  - target: Cardiac Dysfunction and Pulmonary Edema
    relationship: CORRELATES_WITH
    direction: POSITIVE
    endpoint_context: DIAGNOSTIC
    interpretation: >-
      A candidate marker, not an established one: one cross-sectional
      single-centre study of 49 patients, without serial measurement.
    evidence:
    - reference: PMID:39842516
      reference_title: New biomarkers in scorpion stings.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      quote_role: PRIMARY_RESULT
      snippet: "The cut-off values determined for both biomarkers showed a sensitivity of 92.3%."
      explanation: >-
        The sensitivity at the study's own cut-off, which is what a diagnostic
        readout claim rests on.
- name: Heart-type fatty acid binding protein (FABP3)
  presence: INCREASED
  subtype: Neurotoxic
  biomarker_term:
    preferred_term: heart-type fatty acid binding protein
    term:
      id: NCIT:C20974
      label: Fatty Acid-Binding Protein, Heart
  notes: >-
    Curated with sST2 because they come from the same study and carry the same
    caveats. FABP3 is a small cytosolic protein released early from injured
    myocytes, so on mechanism it belongs beside CK-MB rather than beside
    NT-proBNP - but the study that measures it here evaluates it against
    echocardiographic dysfunction, so that is the node this readout points at.
  evidence:
  - reference: PMID:39842516
    reference_title: New biomarkers in scorpion stings.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: PRIMARY_RESULT
    snippet: "The biomarkers of sST2 and FABP-3 showed an association with left ventricular dysfunction, presenting AUCs of 0.77 and 0.81, respectively."
    explanation: >-
      The result establishing FABP3 as a candidate marker here, and the better
      discriminating of the two new markers tested.
  readouts:
  - target: Cardiac Dysfunction and Pulmonary Edema
    relationship: CORRELATES_WITH
    direction: POSITIVE
    endpoint_context: DIAGNOSTIC
    interpretation: >-
      Same standing and the same limits as sST2 - 49 patients, one centre, no
      serial sampling - and evaluated against the same echocardiographic
      endpoint.
    evidence:
    - reference: PMID:39842516
      reference_title: New biomarkers in scorpion stings.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      quote_role: PRIMARY_RESULT
      snippet: "The study showed an association between sST2 and FABP-3, as well as the presence of acute cardiac dysfunction, identified by cardiac ultrasound."
      explanation: >-
        The association stated against the endpoint that defines this node -
        acute cardiac dysfunction on ultrasound - rather than against a
        clinical severity grade.
environmental:
- name: Scorpion sting delivering neurotoxic venom
  description: >-
    The exposure is an injection, not an ingestion or an inhalation, which is
    why dose scales with body mass and why children are the ones who die. Stings
    are domestic and rural in the great majority, concentrated in seven regions
    covering some 2.3 billion people.
  exposure_term:
    preferred_term: envenomation by buthid scorpion neurotoxins
    term:
      id: ECTO:0000730
      label: exposure to neurotoxin
  exposure_classifications:
    hazard_agent_type:
    - classification_value: BIOLOGICAL
    exposure_duration:
    - classification_value: ACUTE
  influences_mechanisms:
  - target: Scorpion Venom Neurotoxin Binding to Voltage-Gated Sodium Channels
    environmental_effect: TRIGGERS
    causal_link_type: DIRECT
    description: >-
      The sting is what delivers the toxins to the channels; there is no other
      route into this disease.
    evidence:
    - reference: PMID:34055554
      reference_title: Neurological and Systemic Manifestations of Severe Scorpion Envenomation.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      quote_role: REVIEW_SYNTHESIS
      snippet: "The toxin released by the sting stimulates the autonomic nervous system (ANS), sympathetic and parasympathetic, which activates the coagulation cascade."
      explanation: States the sting-to-mechanism step this edge asserts.
  - target: Venom-Triggered Cardiac IL-1R Signaling and PGE2 Production
    environmental_effect: TRIGGERS
    causal_link_type: DIRECT
    description: >-
      The inflammatory arm is drawn from the exposure rather than from the
      autonomic storm, because in the source it does not run through it: venom
      reaching the heart is recognised directly by resident cardiac cells, not
      by way of neurotransmitter release. An earlier draft hung this edge off
      the storm node while its own description said the two run in parallel,
      which made the graph say something the curation denied.
    evidence:
    - reference: PMID:33116136
      reference_title: Interleukin-1 receptor-induced PGE(2) production controls acetylcholine-mediated cardiac dysfunction and mortality during scorpion envenomation.
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      snippet: "Cardiac fibroblasts respond to TsV and produce PGE2 and IL-1β in vitro."
      explanation: >-
        The venom is sensed by cardiac cells directly, which is what makes this
        an edge from the exposure rather than from the neurotransmitter storm.
  notes: >-
    Bound to `ECTO:0000730` exposure to neurotoxin, anchored on `CHEBI:50910`
    neurotoxin, which is exact for the agent class: the buthid venom's active
    principles are sodium-channel neurotoxins. ECTO has no scorpion, venom or
    sting class. The searches, against the pinned local build the validator
    reads:

    `runoak -i sqlite:obo:ecto search 'l~scorpion'` returns nothing.
    `runoak -i sqlite:obo:ecto search 'l~venom'` returns nothing.
    `runoak -i sqlite:obo:ecto search 'l~arthropod'` returns nothing.
    `runoak -i sqlite:obo:ecto search 'l~bite'` returns nothing.
    `runoak -i sqlite:obo:ecto search 'l~sting'` returns only `ENVO:01000690`
    mass wasting and `XCO:0000002` resting, both substring false positives.
    `runoak -i sqlite:obo:ecto search 't~exposure to neurotoxin'` returns
    `ECTO:0000730`, and `info ECTO:0000730 -O obo` shows it is
    `is_a ECTO:0000485` exposure to chemical with biological effect and
    involves `CHEBI:50910` neurotoxin. Neither it nor its parent is flagged
    Not4Curation.
  evidence:
  - reference: PMID:18579104
    reference_title: "Epidemiology of scorpionism: a global appraisal."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    snippet: "These involve 2.3 billion at risk population."
    explanation: The size of the exposed population across the seven identified risk regions.
- name: Scorpion sting delivering cytotoxic venom
  description: >-
    The same act with a different venom. Hemiscorpius lepturus accounts for
    about a tenth of stings in Khuzestan and for essentially all of the
    cutaneous and haemolytic disease there.
  exposure_term:
    preferred_term: envenomation by Hemiscorpius lepturus cytolytic venom
    term:
      id: ECTO:0000537
      label: exposure to toxin
  exposure_classifications:
    hazard_agent_type:
    - classification_value: BIOLOGICAL
    exposure_duration:
    - classification_value: ACUTE
  influences_mechanisms:
  - target: Cytolytic Venom Membrane Damage
    environmental_effect: TRIGGERS
    causal_link_type: DIRECT
    description: The cytolytic venom is delivered by the same sting route.
  notes: >-
    Bound one level broader than the neurotoxic exposure, to `ECTO:0000537`
    exposure to toxin, because the agent here is a cytolytic enzyme rather than
    a neurotoxin and `ECTO:0000730` would be wrong. `runoak -i sqlite:obo:ecto
    search 't~exposure to toxin'` returns `ECTO:0000537`; the same searches
    recorded on the neurotoxic exposure above show ECTO has no cytotoxin,
    phospholipase or venom class to be more specific with.
  evidence:
  - reference: PMID:9679690
    reference_title: "Cutaneous manifestations of the Hemiscorpius lepturus sting: a clinical study."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Hemiscorpion (Hemiscorpius) lepturus (HL), which is responsible for more than 10% of the scorpion stings in this area"
    explanation: >-
      States this exposure's share of stings in the studied region directly,
      rather than leaving it to be derived as the complement of the buthid 90%.
treatments:
- name: Species-specific antivenom
  description: >-
    Equine F(ab')2 or Fab antivenom against the local species, the only
    treatment that removes venom rather than opposing its effects. In the
    pivotal paediatric trial it cleared the clinical syndrome within four hours
    in every recipient and made circulating venom undetectable, against one of
    seven on placebo.
  therapeutic_modality: OTHER
  treatment_term:
    preferred_term: antivenom administration
    term:
      id: NCIT:C15986
      label: Pharmacotherapy
  notes: >-
    Bound to the generic `NCIT:C15986` because NCIT has no antivenom class
    other than a product-specific one. OLS `q=antivenom, ontology=ncit` and
    `q=antivenin, ontology=ncit` each return only `NCIT:C87794` Coral Snake
    (Micrurus fulvius) Immune Globulin Antivenin (Equine), which names a
    different product; `q=immune globulin therapy, ontology=ncit` returns
    `NCIT:C121331` Intravenous Immunoglobulin Therapy, which is pooled human
    immunoglobulin for immunomodulation and not an antivenom. The sibling
    `Snakebite_Envenoming` entry binds the same generic term for the same
    reason.
  target_mechanisms:
  - target: Scorpion Venom Neurotoxin Binding to Voltage-Gated Sodium Channels
    treatment_effect: INHIBITS
    description: >-
      Antivenom binds circulating venom, so it acts upstream of the channel -
      which is also why it cannot reverse what the channel has already set in
      motion.
    evidence:
    - reference: PMID:19439743
      reference_title: Antivenom for critically ill children with neurotoxicity from scorpion stings.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "Plasma venom concentrations were undetectable in all eight antivenom recipients but in only one placebo recipient 1 hour after treatment (P=0.001)."
      explanation: >-
        Measures the effect on circulating venom directly, which is the
        mechanism this edge asserts rather than the clinical endpoint.
  evidence:
  - reference: PMID:19439743
    reference_title: Antivenom for critically ill children with neurotoxicity from scorpion stings.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The clinical syndrome resolved more rapidly among recipients of the antivenom than among recipients of placebo, with a resolution of symptoms in all eight antivenom recipients versus one of seven placebo recipients within 4 hours after treatment (P=0.001)."
    explanation: The randomised, placebo-controlled result behind this treatment.
  - reference: PMID:24550184
    reference_title: "Efficacy of scorpion antivenom plus prazosin versus prazosin alone for Mesobuthus tamulus scorpion sting envenomation in children: a randomised controlled trial."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The proportion of children deteriorating to clinical grade 3 or 4 was 8% in group A as against 44% in group B (p<0.01)."
    explanation: >-
      A second randomised trial, in children and against a different species,
      measuring the outcome that matters most here - progression to the severe
      grades rather than symptom resolution.
  - reference: PMID:28390429
    reference_title: "Management of scorpion envenoming: a systematic review and meta-analysis of controlled clinical trials."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: PRIMARY_RESULT
    snippet: "Antivenom against Centruroides sp. are effective in reversing the clinical syndrome faster than no antivenom treatment in children (RR, 0.02; 95% CI, 0.01 to 0.06; 322 participants; three trials)."
    explanation: >-
      The pooled estimate across three trials and 322 children, which is the
      strongest form the antivenom claim takes. Note the scope: this is
      Centruroides, and the same meta-analysis reaches a separate conclusion
      for Mesobuthus tamulus, where antivenom is an add-on to prazosin rather
      than a standalone.
  - reference: PMID:28390429
    reference_title: "Management of scorpion envenoming: a systematic review and meta-analysis of controlled clinical trials."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: PRIMARY_RESULT
    snippet: "The polyvalent antivenom against Centruroides sp. in USA/Mexico and the monovalent antivenom against M. tamulus in India are effective for rapid resolution of symptoms."
    explanation: >-
      The species- and product-specific conclusion, quoted because it is what
      makes this treatment "species-specific antivenom" rather than
      "antivenom" - the evidence does not generalise across scorpion genera.
- name: Prazosin
  description: >-
    An alpha-1 adrenergic antagonist, oral, and cheap. It opposes the adrenergic
    arm of the storm directly and is the established treatment for Mesobuthus
    tamulus stings in India, where it is often given without antivenom at all.
  therapeutic_modality: SMALL_MOLECULE
  treatment_term:
    preferred_term: Pharmacotherapy
    term:
      id: NCIT:C15986
      label: Pharmacotherapy
    therapeutic_agent:
    - preferred_term: prazosin
      term:
        id: CHEBI:8364
        label: prazosin
  target_mechanisms:
  - target: Catecholamine-Mediated Myocardial Injury
    treatment_effect: INHIBITS
    description: >-
      Blocking alpha-1 receptors opposes the vasoconstriction and afterload rise
      through which the catecholamine surge injures the myocardium. Note this
      edge is drawn under the canonical hypothesis; under the emerging one
      prazosin would be treating an arm that is not the lethal one.
    evidence:
    - reference: PMID:21209062
      reference_title: "Efficacy and safety of scorpion antivenom plus prazosin compared with prazosin alone for venomous scorpion (Mesobuthus tamulus) sting: randomised open label clinical trial."
      supports: SUPPORT
      directness: INDIRECT
      evidence_source: HUMAN_CLINICAL
      snippet: "Recovery from scorpion sting is hastened by simultaneous administration of scorpion antivenom plus prazosin compared with prazosin alone."
      explanation: >-
        Prazosin resolving the autonomic syndrome in both arms of a randomised
        trial. INDIRECT: a therapeutic response cited as validation of the
        mechanism it targets, and this design compares adding antivenom rather
        than prazosin against nothing.
  evidence:
  - reference: PMID:21209062
    reference_title: "Efficacy and safety of scorpion antivenom plus prazosin compared with prazosin alone for venomous scorpion (Mesobuthus tamulus) sting: randomised open label clinical trial."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Recovery from scorpion sting is hastened by simultaneous administration of scorpion antivenom plus prazosin compared with prazosin alone."
    explanation: >-
      The randomised comparison that positions prazosin: effective enough to
      be the control arm, and improved on by adding antivenom.
  - reference: PMID:21209062
    reference_title: "Efficacy and safety of scorpion antivenom plus prazosin compared with prazosin alone for venomous scorpion (Mesobuthus tamulus) sting: randomised open label clinical trial."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Mean (SD) recovery times in hours for the prazosin plus scorpion antivenom group compared with the prazosin alone groups were: sweating 3 (1.1) v 6.6 (2.6); salivation 1.9 (0.9) v 3 (1.9); priapism 4.7 (1.5) v 9.4 (1.5)."
    explanation: >-
      Resolution times for three autonomic signs in both arms. Read carefully:
      the trial has no placebo, so these numbers measure what adding antivenom
      does on top of prazosin, and the prazosin-alone arm is the slower one.
      Cited here because it shows prazosin alone resolving the storm's signs
      within hours, not because it isolates prazosin's effect - which this
      design cannot do.
- name: Dobutamine
  description: >-
    A beta-1 agonist inotrope for the myocardial depression and cardiogenic
    shock of severe envenomation - supporting the failing ventricle rather than
    acting on the venom or the storm.
  therapeutic_modality: SMALL_MOLECULE
  treatment_term:
    preferred_term: Pharmacotherapy
    term:
      id: NCIT:C15986
      label: Pharmacotherapy
    therapeutic_agent:
    - preferred_term: dobutamine
      term:
        id: CHEBI:4670
        label: dobutamine
  target_mechanisms:
  - target: Cardiac Dysfunction and Pulmonary Edema
    treatment_effect: MODULATES
    description: >-
      Dobutamine acts on neither the venom nor the storm. It supports the
      failing ventricle at the node where both hypothesis arms converge,
      which is why it is drawn here and nowhere upstream. MODULATES rather
      than INHIBITS: beta-1 agonism raises cardiac output against a
      depressed myocardium, it does not remove the cause of the depression.
    evidence:
    - reference: PMID:32428515
      reference_title: Dobutamine in the treatment of severe scorpion envenoming.
      supports: SUPPORT
      directness: DIRECT
      evidence_source: HUMAN_CLINICAL
      quote_role: PRIMARY_RESULT
      snippet: "Our study confirms that cardiac dysfunction following scorpion envenomation in Tunisia improved well and safely under dobutamine infusion."
      explanation: >-
        Measures the effect on this node directly - cardiac index rose from
        2.7 to 3.6 L/min/m2 at the lowest dose - in 21 Swan-Ganz-monitored
        patients, which is the claim this edge makes.
  evidence:
  - reference: PMID:32428515
    reference_title: Dobutamine in the treatment of severe scorpion envenoming.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: PRIMARY_RESULT
    snippet: "We included 21 patients with pulmonary edema or hemodynamic shock following scorpion envenoming."
    explanation: >-
      The dedicated dobutamine study, and its population: every patient had
      the pulmonary oedema or shock this treatment is for. An uncontrolled
      dose-ranging series, not a trial.
  - reference: PMID:32428515
    reference_title: Dobutamine in the treatment of severe scorpion envenoming.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: PRIMARY_RESULT
    snippet: "The optimal dose of dobutamine to start with was between 5 and 10 μg/kg/min."
    explanation: >-
      The dosing conclusion, which is the practical output of the study.
      Quoted with the source's own non-breaking space before the unit, since
      the reference validator matches bytes.
  - reference: PMID:37018229
    reference_title: "Scorpion envenomation-associated myocarditis: A systematic review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The management typically included inotropes (especially dobutamine), prazosin, diuretics, nitroglycerine and digoxin, when indicated."
    explanation: Places dobutamine as the usual inotrope in the reviewed cases.
- name: Mechanical ventilation and intensive supportive care
  description: >-
    Required in about a third of the myocarditis cases, and the reason outcome
    depends so heavily on how far the patient is from an intensive care bed.
  therapeutic_modality: DEVICE
  treatment_term:
    preferred_term: Mechanical Ventilation
    term:
      id: NCIT:C70909
      label: Mechanical Ventilation
  target_mechanisms:
  - target: Cardiac Dysfunction and Pulmonary Edema
    treatment_effect: MODULATES
    description: >-
      Ventilation takes over gas exchange against the alveolar flooding this
      node produces. It acts on the consequence, not on the failing ventricle,
      and nothing it does shortens the myocardial recovery - which is why the
      edge is MODULATES and why outcome tracks distance from an intensive care
      bed rather than anything pharmacological.
    evidence:
    - reference: PMID:37018229
      reference_title: "Scorpion envenomation-associated myocarditis: A systematic review."
      supports: SUPPORT
      directness: INDIRECT
      evidence_source: HUMAN_CLINICAL
      snippet: "Mechanical ventilation was required in 36.7% of the patients."
      explanation: >-
        INDIRECT, and the limit is worth stating: this establishes that the
        myocarditis at this node is what drives the need for ventilation in
        over a third of cases. No cited source here measures what ventilation
        does to the node once started.
  evidence:
  - reference: PMID:37018229
    reference_title: "Scorpion envenomation-associated myocarditis: A systematic review."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Mechanical ventilation was required in 36.7% of the patients."
    explanation: The proportion needing ventilation, in the pooled myocarditis series.
- name: Early dexamethasone
  description: >-
    Not established practice. In envenomed mice, high-dose dexamethasone
    abolished heart failure and mortality, and the authors propose giving it
    very early - before antiserum - on the grounds that it reaches a pathway
    antivenom does not. Recorded because it is a mechanism-directed proposal
    with a specific rationale, not because there is human evidence for it.
  therapeutic_modality: SMALL_MOLECULE
  treatment_term:
    preferred_term: Pharmacotherapy
    term:
      id: NCIT:C15986
      label: Pharmacotherapy
    therapeutic_agent:
    - preferred_term: dexamethasone
      term:
        id: CHEBI:41879
        label: dexamethasone
  target_mechanisms:
  - target: Venom-Triggered Cardiac IL-1R Signaling and PGE2 Production
    treatment_effect: INHIBITS
    description: >-
      Suppressing the inflammatory arm at its origin, which is where the
      emerging hypothesis locates the lethal pathway.
    evidence:
    - reference: PMID:33116136
      reference_title: Interleukin-1 receptor-induced PGE(2) production controls acetylcholine-mediated cardiac dysfunction and mortality during scorpion envenomation.
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      snippet: "IL-1R deficiency, the treatment with a high dose of dexamethasone or blockage of parasympathetic signaling using atropine or vagotomy, abolished heart failure and mortality of envenomed mice."
      explanation: >-
        Dexamethasone is one of four interventions abolishing the outcome,
        which is what makes this a mechanism-directed edge rather than an
        empirical one.
  evidence:
  - reference: PMID:33116136
    reference_title: Interleukin-1 receptor-induced PGE(2) production controls acetylcholine-mediated cardiac dysfunction and mortality during scorpion envenomation.
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: "we propose the use of dexamethasone administration very early after envenomation, even before antiserum"
    explanation: >-
      The proposal itself, quoted so the entry records it as the authors'
      recommendation from a mouse model rather than as practice.
  - reference: PMID:33116136
    reference_title: Interleukin-1 receptor-induced PGE(2) production controls acetylcholine-mediated cardiac dysfunction and mortality during scorpion envenomation.
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: "we introduce a novel pathway that is targeted by dexamethasone, but not by anti-scorpion venom serum"
    explanation: >-
      The argument for adding it rather than relying on antivenom: the two act
      on different things.
  - reference: PMID:39628768
    reference_title: "Immunosuppressive therapies in scorpion envenomation: new perspectives for treatment."
    supports: SUPPORT
    evidence_source: OTHER
    quote_role: REVIEW_SYNTHESIS
    snippet: "In recent decades, new research has revealed that the immune system plays an important role in triggering immunopathological reactions during scorpion envenoming, which places it as a therapeutic target; however, few clinical studies have been conducted."
    explanation: >-
      Confirms both halves of this treatment's status: the immune system is
      taken seriously as a target, and the clinical evidence for acting on it
      does not yet exist. Graded OTHER because the quoted sentence is a
      review's assessment of a field rather than a described study.
- name: Atropine
  description: >-
    The drug the two hypotheses disagree about most sharply. In envenomed mice
    it is one of four interventions that abolish cardiac failure and death, and
    the emerging hypothesis predicts it should work. In human practice it is
    advised against for routine use - it blocks sweating, which children need
    for temperature regulation, and it potentiates the adrenergic arm the
    canonical hypothesis holds responsible. Both positions are curated here
    because the disagreement is the point: the same drug is protective or
    harmful depending on which arm is lethal.
  therapeutic_modality: SMALL_MOLECULE
  treatment_term:
    preferred_term: Pharmacotherapy
    term:
      id: NCIT:C15986
      label: Pharmacotherapy
    therapeutic_agent:
    - preferred_term: atropine
      term:
        id: CHEBI:16684
        label: atropine
  target_mechanisms:
  - target: Excessive Vagal Acetylcholine Release at the Heart
    treatment_effect: INHIBITS
    description: >-
      Muscarinic blockade at the heart, which is the effector step of the
      emerging hypothesis. This edge is drawn under that hypothesis; under the
      canonical one atropine is acting on an arm that is not the lethal one,
      and unopposing the one that is.
    evidence:
    - reference: PMID:33116136
      reference_title: Interleukin-1 receptor-induced PGE(2) production controls acetylcholine-mediated cardiac dysfunction and mortality during scorpion envenomation.
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      quote_role: PRIMARY_RESULT
      snippet: "Interestingly, in contrast to treatment with propranolol, the administration of atropine, a nonselective muscarinic antagonist, rescued the mice from mortality"
      explanation: >-
        The comparison that makes this edge mechanistic rather than empirical:
        blocking the parasympathetic arm rescued the mice where blocking the
        sympathetic arm did not.
  evidence:
  - reference: PMID:22826633
    reference_title: Emerging options for the management of scorpion stings.
    supports: REFUTE
    evidence_source: OTHER
    quote_role: REVIEW_SYNTHESIS
    snippet: "In general, antiparasympathetic drugs, such as atropine, are not recommended routinely in the treatment of scorpion envenoming."
    explanation: >-
      The standing human recommendation, and it is against routine use.
      REFUTE against treating atropine as an established therapy here.
      Graded OTHER because the quoted sentence is a review's recommendation
      rather than a described study.
  - reference: PMID:22826633
    reference_title: Emerging options for the management of scorpion stings.
    supports: SUPPORT
    evidence_source: OTHER
    quote_role: REVIEW_SYNTHESIS
    snippet: "However, these drugs can be useful in cases of severe bradycardia or complete atrioventricular block, which are sometimes observed."
    explanation: >-
      The narrow indication the same review does accept, quoted so the entry
      records what atropine is actually used for rather than only what it is
      advised against.
  notes: >-
    The reason given against routine use is itself mechanistic and worth
    reading next to the pathograph: blocking the parasympathetic arm leaves
    the sympathetic one unopposed, which is the arm the canonical hypothesis
    says does the damage. So the human caution and the mouse result are not
    simply in conflict - they are what the two hypotheses each predict.
- name: Plasma exchange and renal replacement therapy
  description: >-
    Supportive treatment of the cytotoxic branch once thrombotic
    microangiopathy and renal failure are established. Curated because that
    branch otherwise reaches its terminal nodes with nothing acting on it,
    and because the mechanism the entry curates - an acquired ADAMTS13
    deficiency with an autoantibody against the enzyme - is the same one
    plasma exchange addresses in the primary thrombotic microangiopathies,
    by removing the antibody and replacing the enzyme.
  therapeutic_modality: DEVICE
  treatment_term:
    preferred_term: therapeutic plasma exchange
    term:
      id: NCIT:C15304
      label: Plasmapheresis
  notes: >-
    Bound to `NCIT:C15304` Plasmapheresis as the nearest clinical-action term;
    OLS `q=Therapeutic Plasma Exchange, ontology=ncit` returns `NCIT:C133348`
    Therapeutic Exchange Plasma, which names the blood product rather than the
    procedure, and `NCIT:C15304`. The existing `Atypical_Hemolytic_Uremic_Syndrome`
    and `Heparin-Induced_Thrombocytopenia` entries bind the same term for the
    same reason. `DEVICE` follows this entry's mechanical-ventilation record:
    an extracorporeal circuit is the closest platform the modality enum
    offers for an apheresis procedure.
  target_mechanisms:
  - target: Thrombotic Microangiopathy and Acute Kidney Injury
    treatment_effect: MODULATES
    description: >-
      Acting at the terminal node of the cytotoxic branch rather than upstream
      of it: by the time plasma exchange is started the venom has already
      lysed the erythrocytes. Read the evidence carefully - the cited case
      establishes that the combination was given and the child recovered, not
      that plasma exchange is what produced the recovery. No controlled
      evidence exists for it in this disease.
    evidence:
    - reference: PMID:40034936
      reference_title: Hemolytic Uremic Syndrome Secondary to Scorpion Envenomation in a 7-Year-Old Boy from Southwestern Iran.
      supports: SUPPORT
      directness: INDIRECT
      evidence_source: HUMAN_CLINICAL
      quote_role: PRIMARY_RESULT
      snippet: "The patient received supportive treatment, hemodialysis, and plasma exchange, and was discharged after 30 days of hospitalization."
      explanation: >-
        A single case report of use with survival. INDIRECT: an uncontrolled
        therapeutic response cited in support of the mechanism it is thought
        to act on, with three interventions given together and no way to
        separate them.
- name: Anti-heminecrolysin nanobody
  description: >-
    A candidate, not a treatment. Heminecrolysin is the haemolytic and
    dermonecrotic fraction of Hemiscorpius lepturus venom - the molecule
    behind the cytotoxic branch - and a camelid single-domain antibody
    against it neutralised both activities in mice. Recorded because it is
    the only agent in the entry aimed at the cytolytic lesion itself rather
    than at its consequences, and because the equine antivenom it would
    replace causes anaphylaxis.
  therapeutic_modality: NANOBODY
  treatment_term:
    preferred_term: Pharmacotherapy
    term:
      id: NCIT:C15986
      label: Pharmacotherapy
  notes: >-
    No `therapeutic_agent` binding: F7Nb is a research construct with no
    ontology identity, and NCIT has no generic single-domain-antibody class
    to fall back on - OLS `q=Single Domain Antibody, ontology=ncit` returns
    only named products (`NCIT:C211548` Lutetium Lu 177 Anti-PD-L1 Nanobody
    RAD204, `NCIT:C120068` Anti-CEACAM6 AFAIKL2 Antibody Fragment/Jack Bean
    Urease Immunoconjugate L-DOS47) and unrelated constructs. `NCIT:C20401`
    Monoclonal Antibody was considered and rejected: a nanobody is a
    single-domain fragment, not a monoclonal antibody, and the distinction is
    exactly what this treatment turns on.
  target_mechanisms:
  - target: Cytolytic Venom Membrane Damage
    treatment_effect: INHIBITS
    description: >-
      Neutralising the venom fraction that does the lysing, upstream of the
      haemolysis - which is the one point on this branch where a treatment
      could act before the damage rather than after it.
    evidence:
    - reference: PMID:24891523
      reference_title: A camelid antibody candidate for development of a therapeutic agent against Hemiscorpius lepturus envenomation.
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      quote_role: PRIMARY_RESULT
      snippet: "The in vivo neutralization tests demonstrated that F7Nb had good antihemolytic and antidermonecrotic effects against HNc in all tested mice."
      explanation: >-
        Both activities of the toxin neutralised in vivo, which is the claim
        this edge makes. Mouse only.
  evidence:
  - reference: PMID:24891523
    reference_title: A camelid antibody candidate for development of a therapeutic agent against Hemiscorpius lepturus envenomation.
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    quote_role: PRIMARY_RESULT
    snippet: "Hence, this Nb is a potential leading novel candidate for treating H. lepturus scorpionism in the near future."
    explanation: >-
      The authors' own statement of where this stands - a candidate for
      development, quoted so the entry does not read it as available therapy.
  - reference: PMID:24891523
    reference_title: A camelid antibody candidate for development of a therapeutic agent against Hemiscorpius lepturus envenomation.
    supports: SUPPORT
    evidence_source: OTHER
    quote_role: BACKGROUND
    snippet: "However, this immunotherapy creates serious side effects, including anaphylactic shock sometimes even leading to death."
    explanation: >-
      The problem with the existing equine antivenom that motivates a
      replacement. BACKGROUND: the paper's framing of the clinical situation,
      not its own result. Graded OTHER because the quoted sentence names an
      adverse-effect profile without describing the study behind it.
prevalence:
- population: Worldwide
  measure_type: ANNUAL_INCIDENCE
  rate_denominator: POPULATION_PER_YEAR
  notes: >-
    More than 1.2 million stings a year across the seven identified risk
    regions. Recorded as a count rather than a rate: the source gives a global
    sting total against a 2.3 billion at-risk denominator that is itself an
    estimate, so no per-100,000 figure can be derived from it honestly.
  prevalence_class: NOT_YET_DOCUMENTED
  evidence:
  - reference: PMID:18579104
    reference_title: "Epidemiology of scorpionism: a global appraisal."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    snippet: "The annual number of scorpion stings exceeds 1.2 million leading to more than 3250 deaths (0.27%)."
    explanation: The global sting count and case fatality this record reports.
- population: Brazil
  measure_type: ANNUAL_INCIDENCE
  prevalence_class: BAND_1_5_PER_10000
  rate_per_100000: 70.0
  rate_denominator: PERSON_YEARS
  notes: >-
    A national rate, in contrast to the worldwide record above which is a count
    with no usable denominator. Recorded because Brazil is where the incidence
    is best measured and because the figure is rising there.
  evidence:
  - reference: PMID:37902581
    reference_title: "Moderate or severe scorpion sting: identification of risk factors."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: BACKGROUND
    snippet: "reaching approximately 70 cases per 100,000 inhabitants-years in 2018"
    explanation: The rate and its denominator, stated per inhabitant-year.
clinical_trials:
- name: NCT00685230
  phase: NOT_APPLICABLE
  status: COMPLETED
  description: >-
    The randomised, double-blind, placebo-controlled paediatric trial of
    Centruroides-specific F(ab')2 antivenom that established the treatment and
    led to US approval. Fifteen children in intensive care; resolution of the
    clinical syndrome within four hours was the primary endpoint.
  target_phenotypes:
  - preferred_term: Local paresthesia at sting site
    term:
      id: HP:0020014
      label: Local paresthesia at bite site
  notes: >-
    `phase: NOT_APPLICABLE` because the registration records no FDA phase for
    it; the cached ClinicalTrials.gov record carries the design and population
    but no phase designation.
  evidence:
  - reference: clinicaltrials:NCT00685230
    reference_title: "Prospective, Randomized, Double-Blind, Controlled Study of Alacramyn® vs. Placebo in Pediatric Patients With Systemic Signs of Scorpion Sting Envenomation"
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Patients stung by Centruroides scorpions develop a clinical syndrome which may require sedation with benzodiazepines and observation for 6 to 28 hours of intensive care monitoring."
    explanation: >-
      The registration's own statement of the syndrome and the standard of
      care this trial was testing antivenom against, which is what identifies
      it as the trial reported in PMID:19439743.
- name: CTRI/2013/09/004002
  phase: NOT_APPLICABLE
  status: COMPLETED
  description: >-
    The Indian paediatric randomised trial of scorpion antivenom plus prazosin
    against prazosin alone, reported in PMID:24550184. Registered on CTRI
    rather than ClinicalTrials.gov, which is why it is keyed on its WHO ICTRP
    identifier.
  notes: >-
    Registered retrospectively - the ICTRP record shows registration in
    September 2013 against first enrolment in June 2012, with Prospective
    Registration recorded as No. Worth knowing when weighing the result.
  evidence:
  - reference: ICTRP:CTRI/2013/09/004002
    reference_title: "A Randomized open label clinical trial to find out efficacy of scorpion anti- Venom plus prazosin combination in children of scorpion sting envenomation"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "| Register | CTRI |"
    explanation: >-
      The WHO ICTRP registration record establishing this trial's identity on
      a non-ClinicalTrials.gov primary registry.
  - reference: ICTRP:CTRI/2013/09/004002
    reference_title: "A Randomized open label clinical trial to find out efficacy of scorpion anti- Venom plus prazosin combination in children of scorpion sting envenomation"
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "| Prospective Registration | No |"
    explanation: >-
      The retrospective registration, quoted rather than asserted because it
      bears on how the trial's result should be read.
diagnosis:
- name: Transthoracic echocardiography
  description: >-
    The reference standard the whole biochemical section is measured against,
    and the test that decides management: it separates the child with an
    autonomic syndrome who will recover from the one with left ventricular
    failure who needs an intensive care bed. Reversibility is the point -
    ventricular function recovers in almost all survivors, so a depressed
    ejection fraction here is a reason to escalate support rather than a
    prognosis.
  diagnosis_term:
    preferred_term: echocardiography
    term:
      id: NCIT:C16525
      label: Echocardiography Test
  markers: Ejection fraction, shortening fraction, left ventricular dysfunction
  results: >-
    Left ventricular dysfunction in roughly a quarter of patients presenting
    with signs of severity.
  evidence:
  - reference: PMID:39842516
    reference_title: New biomarkers in scorpion stings.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: BACKGROUND
    snippet: "The resources currently available for diagnosing cardiac dysfunction caused by scorpion stings, the most common cause of death, are echocardiograms and laboratory tests, such as troponin, creatine phosphokinase-MB (CKMB), and Brain natriuretic peptide (BNP)."
    explanation: >-
      States the diagnostic standard of care for this disease, and names the
      same laboratory markers the `biochemical:` section curates. BACKGROUND
      because it frames the study rather than reporting its result.
  - reference: PMID:39842516
    reference_title: New biomarkers in scorpion stings.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: PRIMARY_RESULT
    snippet: "Left ventricular dysfunction was identified in 13 patients (26.5%), with 7 cases classified as severe."
    explanation: >-
      The yield of the test in a series selected for signs of severity on
      admission, which is the population it is used in.
  notes: >-
    Curated as a diagnosis rather than as a biomarker because it is the
    endpoint every marker in the `biochemical:` section is evaluated against -
    sST2 and FABP3 report AUCs against cardiac ultrasound, and proBNP is
    correlated against ejection and shortening fraction. Reading the two
    sections together, the markers are candidates for triaging who gets an
    echocardiogram sooner, not replacements for it.
- name: Serial ECG and cardiac monitoring
  description: >-
    Continuous monitoring with periodic ECG over the first 24 hours, which is
    the window in which the cardiac complications appear and in which almost
    all deaths occur.
  diagnosis_term:
    preferred_term: electrocardiography
    term:
      id: NCIT:C38053
      label: Electrocardiography
  markers: Rhythm, rate, repolarization change
  evidence:
  - reference: PMID:33094659
    reference_title: "Scorpion sting: N-terminal fragment of proB-type natriuretic peptide as an early predictor of pediatric cardiotoxicity."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: PRIMARY_RESULT
    snippet: "subjected to 24 h cardiac monitoring with periodic ECG every 6 h"
    explanation: >-
      The monitoring protocol applied to all 483 symptomatic children in this
      prospective series, which is what makes it the observed practice rather
      than a recommendation.
  notes: >-
    Recorded because the entry carries both `Tachycardia` and `Bradycardia`
    phenotypes, and which of the two a patient shows is the bedside signal
    that most directly bears on which autonomic arm is dominant - the question
    the entry's two `mechanistic_hypotheses` disagree about. No cited source
    here claims ECG resolves that question.
animal_models:
- name: Lethally envenomed C57BL/6 mouse (Tityus serrulatus venom, 180 ug/kg i.p.)
  species: Mouse
  genotype: C57BL/6 wild type, with Il1r1-/-, Nlrp3-/-, Asc-/- and Casp1/11-/- knockouts used as mechanistic controls
  publication: PMID:33116136
  description: >-
    The model the whole emerging hypothesis rests on. Mice given a lethal
    intraperitoneal dose of Tityus serrulatus venom develop sweating, ocular
    and nasal secretion, lethargy and convulsion within an hour, with
    measurable rises in plasma adrenaline and acetylcholine, falling arterial
    pressure and heart rate, and death in half to all animals. Its value is
    that it is interventional where the human literature is observational:
    genetic knockouts and drugs can be applied to individual steps.
  evidence:
  - reference: PMID:33116136
    reference_title: Interleukin-1 receptor-induced PGE(2) production controls acetylcholine-mediated cardiac dysfunction and mortality during scorpion envenomation.
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: "Lethally envenomed C57Bl/6 (WT) mice (TsV, 180"
    explanation: >-
      The strain, the venom and the dose that define this model. Quoted short
      because the source renders the units with thin spaces and a minus-sign
      superscript immediately after; the full dose is stated in the model
      description and in `genotype` above.
  - reference: PMID:33116136
    reference_title: Interleukin-1 receptor-induced PGE(2) production controls acetylcholine-mediated cardiac dysfunction and mortality during scorpion envenomation.
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: "These data confirm that lethally envenomed mice present clinical autonomic manifestations similar to those observed in humans"
    explanation: >-
      The authors' own fidelity claim for the model, and the basis for
      treating it as informative about the human syndrome at all.
  modeled_mechanisms:
  - target: Autonomic Neurotransmitter Storm
    relationship: RECAPITULATES
    fidelity: MODERATE
    model_scale: ORGANISM
    description: >-
      Both arms of the storm are reproduced and measured directly in plasma -
      adrenaline and acetylcholine together - alongside the autonomic clinical
      signs that define the syndrome in people.
    limitations: >-
      The route and dose are not those of a sting: an intraperitoneal bolus at
      a defined lethal dose is not a subcutaneous injection of unknown
      quantity, and nothing in the model reproduces the dependence on body
      mass that makes this a disease of children.
    readouts:
    - name: Plasma adrenaline and acetylcholine
      target: Autonomic Neurotransmitter Storm
      direction: INCREASED
      interpretation: >-
        Simultaneous elevation of both transmitters is the defining
        measurement of this node, and the reason the entry does not treat the
        storm as adrenergic alone.
      evidence:
      - reference: PMID:33116136
        reference_title: Interleukin-1 receptor-induced PGE(2) production controls acetylcholine-mediated cardiac dysfunction and mortality during scorpion envenomation.
        supports: SUPPORT
        evidence_source: MODEL_ORGANISM
        snippet: "We detected a dramatic increase in the concentration of adrenaline and ACh compared to PBS-inoculated mice"
        explanation: The measurement itself, against a vehicle control.
    evidence:
    - reference: PMID:33116136
      reference_title: Interleukin-1 receptor-induced PGE(2) production controls acetylcholine-mediated cardiac dysfunction and mortality during scorpion envenomation.
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      snippet: "exhibited sweating, ocular secretion, nasal secretion, lethargy, and convulsion"
      explanation: >-
        The autonomic clinical picture reproduced in the model, which is what
        makes it informative for this node.
  - target: Venom-Triggered Cardiac IL-1R Signaling and PGE2 Production
    relationship: RECAPITULATES
    fidelity: UNKNOWN
    model_scale: CELLULAR
    description: >-
      This node exists only because of this model. Every step of it - the
      inflammasome-dependent IL-1 beta, the sustained PGE2, and the IL-1R
      requirement - was established here and has never been shown in a person.
    limitations: >-
      Fidelity is UNKNOWN rather than low or moderate because there is no
      human counterpart to compare against: the one human study of this axis
      reports an association between circulating IL-1 beta and cardiac
      abnormality and does not test the pathway.
    divergences:
    - divergence_type: SPECIES_MISMATCH
      materiality: QUALIFYING
      description: >-
        Tityus serrulatus is the Brazilian species this work uses, while most
        of the world's scorpion mortality is caused by Androctonus, Leiurus,
        Mesobuthus and Centruroides on other continents, whose venoms differ
        in toxin composition. Whether their venoms are sensed the same way by
        cardiac innate immunity is untested.
    - divergence_type: BOUNDARY_OMISSION
      materiality: QUALIFYING
      description: >-
        The sting is outside the model. Venom is delivered as an
        intraperitoneal bolus, so absorption from a subcutaneous depot, the
        dose actually injected by a scorpion, and the delay before care - all
        of which govern human outcome - are not represented.
    evidence:
    - reference: PMID:33116136
      reference_title: Interleukin-1 receptor-induced PGE(2) production controls acetylcholine-mediated cardiac dysfunction and mortality during scorpion envenomation.
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      snippet: "Here, we show that scorpion envenomation induces autonomic hyperactivation and heart inflammation in mice."
      explanation: >-
        The claim this link carries, stated by the authors with its species
        restriction in the same sentence.
  - target: Cardiac Dysfunction and Pulmonary Edema
    relationship: PARTIALLY_RECAPITULATES
    fidelity: MODERATE
    model_scale: ORGANISM
    description: >-
      Envenomed mice develop falling arterial pressure and heart rate within
      an hour and die, which is the cardiovascular collapse this node
      describes.
    limitations: >-
      The model's cardiac endpoint is haemodynamic collapse and death within
      about an hour. The human node includes pulmonary oedema and a
      myocarditis that is reversible over days in survivors, neither of which
      this model reports - so it captures the fatal arm and not the recovery
      arm that most patients follow.
    readouts:
    - name: Mean arterial pressure and heart rate
      target: Cardiac Dysfunction and Pulmonary Edema
      direction: DECREASED
      interpretation: >-
        Falling pressure and falling rate together is the haemodynamic
        signature the cholinergic account predicts.
      evidence:
      - reference: PMID:33116136
        reference_title: Interleukin-1 receptor-induced PGE(2) production controls acetylcholine-mediated cardiac dysfunction and mortality during scorpion envenomation.
        supports: SUPPORT
        evidence_source: MODEL_ORGANISM
        snippet: "we observed cardiac disorders with diminished mean arterial pressure and heart rates"
        explanation: The measured cardiovascular outcome in envenomed mice.
discussions:
- discussion_id: which_autonomic_arm_kills
  kind: KNOWLEDGE_GAP
  prompt: >-
    Which arm of the autonomic storm actually produces the fatal cardiac
    dysfunction in human scorpion envenomation - the adrenergic one, or the
    IL-1R/PGE2-driven cholinergic one?
  attaches_to:
  - pathophysiology#Catecholamine-Mediated Myocardial Injury
  - pathophysiology#Excessive Vagal Acetylcholine Release at the Heart
  - mechanistic_hypotheses#adrenergic_catecholamine_storm
  - mechanistic_hypotheses#il1r_pge2_cholinergic_axis
  rationale: >-
    Both arms are real and both are measurable in the same envenomed animal -
    adrenaline and acetylcholine rise together. The question is which one the
    heart failure follows from, and the two answers point at opposite drugs.
    The canonical account is adrenergic, and prazosin's clinical benefit is
    usually read as supporting it. The mouse account is cholinergic, and it is
    supported by something stronger than a correlation: IL-1R knockout,
    dexamethasone, atropine and vagotomy each abolish mortality, which is four
    interventions at three different points of one pathway.

    What makes this more than an academic dispute is that the two accounts
    prescribe differently. Under the canonical model an alpha-1 blocker treats
    the lethal mechanism; under the emerging one it treats a real but
    non-lethal arm while the fatal pathway runs untouched - including, the
    authors note, untouched by antivenom. A trial of early dexamethasone or of
    atropine in human envenomation would separate them; none has been done.

    Note also that the evidence is asymmetric in kind, not just in strength.
    The adrenergic account rests on human clinical observation and on a
    therapeutic response; the cholinergic one rests on mechanistic intervention
    in mice. Neither body of evidence is of the type that would refute the
    other.
  evidence:
  - reference: PMID:15687982
    reference_title: "[Cardiovascular dysfunction following severe scorpion envenomation. Mechanisms and physiopathology]."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    quote_role: REVIEW_SYNTHESIS
    snippet: "Adrenergic myocarditis, toxic myocarditis and myocardial ischemia are the 3 mechanisms that explain the cardiac dysfunction."
    explanation: The canonical side of the disagreement, in a human clinical review.
  - reference: PMID:33116136
    reference_title: Interleukin-1 receptor-induced PGE(2) production controls acetylcholine-mediated cardiac dysfunction and mortality during scorpion envenomation.
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: "IL-1R deficiency, the treatment with a high dose of dexamethasone or blockage of parasympathetic signaling using atropine or vagotomy, abolished heart failure and mortality of envenomed mice."
    explanation: >-
      The other side, and the reason it cannot be dismissed as correlation -
      four interventions on one pathway, each abolishing the outcome.
- discussion_id: il1r_axis_is_mouse_only
  kind: HUMAN_MODEL_MISMATCH
  prompt: >-
    Does the IL-1R/PGE2/acetylcholine axis shown in envenomed mice operate in
    human scorpion envenomation?
  attaches_to:
  - pathophysiology#Venom-Triggered Cardiac IL-1R Signaling and PGE2 Production
  - pathophysiology#Excessive Vagal Acetylcholine Release at the Heart
  - treatments#Early dexamethasone
  rationale: >-
    Every step of this pathway - the inflammasome-dependent IL-1 beta, the
    sustained PGE2, the EP2/EP4-mediated acetylcholine release, and the rescue
    by dexamethasone, atropine or vagotomy - was established in mice given
    Tityus serrulatus venom intraperitoneally at a defined lethal dose. That is
    a well-controlled demonstration and it is not a human result.

    Three specific reasons to hold the translation open. The route and dose are
    not those of a sting: an intraperitoneal bolus at 180 micrograms per
    kilogram is not a subcutaneous envenomation of uncertain quantity. The
    species is one whose venom has been studied in Brazil, while most of the
    world's scorpion mortality is caused by other genera on other continents.
    And the human evidence that does exist for an inflammatory contribution is
    correlational - circulating IL-1 beta separates patients with and without
    cardiac abnormality - which is consistent with the pathway being causal,
    with it being a marker of severity, and with both. Note that the same
    study found the pancreatic association statistically insignificant, so the
    human data support the cardiac half of the mouse account and not the
    pancreatic half, even though the paper's title names both.

    This is filed as a model mismatch rather than a knowledge gap because the
    evidence is not absent: it exists, it is good, and what is open is whether
    it transfers. Resolving it needs a human study, and the obvious one - early
    dexamethasone against standard care - is also the one the mouse work
    proposes.
  evidence:
  - reference: PMID:33116136
    reference_title: Interleukin-1 receptor-induced PGE(2) production controls acetylcholine-mediated cardiac dysfunction and mortality during scorpion envenomation.
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: "PGE2 signaling via EP2/4 receptors mediates excessive ACh release, which in turn causes the heart failure of envenomed mice"
    explanation: >-
      The pathway whose translation is in question, stated with its species
      restriction in the same clause.
  - reference: PMID:41327440
    reference_title: "The correlation between Interleukin 1 β (IL-1β) as an inflammatory marker and Malondialdehyde (MDA) as a lipid peroxidation marker and the development of cardiac and pancreatic complications in humans suspected to scorpion poisoning."
    supports: SUPPORT
    directness: INDIRECT
    evidence_source: MODEL_ORGANISM
    quote_role: BACKGROUND
    snippet: "Recent experimental studies on animals were held to prove the correlation between interleukin 1 β (IL-1β), lipid peroxidation and nitric oxide (NO) production in the development of cardiac and pancreatic abnormalities after scorpion venom exposure."
    explanation: >-
      The one human study on this axis opens by stating that the causal work
      was done in animals, which is the mismatch this discussion is about.
      Graded MODEL_ORGANISM because `evidence_source` classifies the evidence
      the quoted text describes, and this sentence describes animal studies -
      the same rule the entry applies in the other direction elsewhere.
  - reference: PMID:41327440
    reference_title: "The correlation between Interleukin 1 β (IL-1β) as an inflammatory marker and Malondialdehyde (MDA) as a lipid peroxidation marker and the development of cardiac and pancreatic complications in humans suspected to scorpion poisoning."
    supports: SUPPORT
    directness: INDIRECT
    evidence_source: HUMAN_CLINICAL
    snippet: "Regarding cardiac abnormality, there were significant statistical differences with both levels of IL-1β and MDA."
    explanation: >-
      The study's own human result, and the whole of it: IL-1 beta separates
      patients with and without cardiac abnormality. INDIRECT because an
      association between a cytokine level and a complication does not
      establish the causal pathway the mouse work describes.

📚

References & Deep Research

Deep Research

1

Deep research results are used as seeds for research; they do not undergo the same validation as the main records and may contain errors. How we use deep research.

Evaluations and curation notes (3)

Record notes

No GeneReviews chapter exists for this disease, and none is expected: it is an acquired envenomation with no Mendelian basis, so `just check-genereviews` returns NO_CHAPTER for both Bookshelf collections. There is likewise no `genetic:` section. The research report searched for host susceptibility loci and found none established; the age dependence that dominates outcome is body mass and cardiovascular reserve rather than genotype, which is recorded in the `environmental` risk prose instead of being curated as disease genes. Three scope exclusions, recorded so they read as decisions rather than oversights. **Only alpha-toxins are modelled.** Scorpion venom also carries beta-NaTx, which shifts the sodium-channel activation threshold rather than blocking inactivation, and potassium-channel toxins; neither is in the pathograph, because the entry's chain rests on the structurally resolved site-3 mechanism and adding the others would mean asserting a chain the cited sources do not resolve. **The takotsubo analogy is not curated.** `PMID:26135709` proposes scorpion cardiomyopathy as a model for takotsubo syndrome, which is a genuinely interesting parallel to the catecholamine node - but it is a Letter with no abstract in PubMed, so there is nothing quotable and nothing can be built on it. Its cache file stays committed because the deep-research report cites it; it is the entry that does not, and this sentence is the reason. **The cytotoxic branch stops at the renal outcome.** Hepatotoxicity and the late necrotic ulcer's secondary infection are both reported for Hemiscorpius lepturus and are not modelled here.

Review round 1b: diagnosis section, ventilation join, four blue suggestions · 2026-09-18T14:16:22Z · View source

Second push on the same review. The formal review body landed on the API after the first push, and it carries detail the summary comment did not: two parts of the blocking findings and four blue suggestions. My mistake was answering from the summary rather than waiting for the review object, which cost a cycle. This push closes everything remaining. Remaining parts of the blocking findings. - diagnosis: section added, which finding 1 asked for explicitly and the first push did not deliver. Transthoracic echocardiography (NCIT:C16525) and serial ECG with cardiac monitoring (NCIT:C38053). Echocardiography is curated as a diagnosis rather than as a biomarker because it is the endpoint every marker in the biochemical: section is evaluated against - sST2 and FABP3 report AUCs against cardiac ultrasound, proBNP is correlated against ejection and shortening fraction - and its notes say so, so the two sections read together rather than as duplicates. The ECG record's notes state that the tachycardia/bradycardia split is the bedside signal bearing on which autonomic arm dominates, and state explicitly that no cited source claims ECG resolves that question. - Mechanical ventilation and intensive supportive care now carries target_mechanisms to Cardiac Dysfunction and Pulmonary Edema (MODULATES). The evidence is the 36.7% requirement figure, graded directness INDIRECT, with the explanation saying plainly what it does and does not establish: the node drives the need for ventilation, and no cited source here measures what ventilation does to the node once started. - PMID:28390429, the controlled-trial meta-analysis, was uncited and is now cited twice on the antivenom treatment - the pooled Centruroides RR across 322 children, and the species-specific conclusion, which is what makes this treatment species-specific antivenom rather than antivenom. Blue suggestions, all taken. - S1 neuromuscular cluster: Fasciculations and Tremor added, both wired off Autonomic Neurotransmitter Storm. Note the reviewer offered HP:0002378 for Fasciculations; that CURIE is Hand tremor. The correct term is HP:0002380, which is what is bound. Both were looked up rather than copied. - S2 pancreatitis: Acute pancreatitis (HP:0001735) added with PMID:2028471, which was fetched and uncited. The edge from the storm node is INDIRECT_UNKNOWN_INTERMEDIATES on purpose - the human study measures pancreatic injury and proposes no route, and the murine IL-1R/NO work behind Hyperglycemia concerns islet function rather than acinar damage, so nothing in the sources identifies the intermediates. That is stated in the edge description rather than glossed. - S3 beta-NaTx and KTx: recorded as an explicit exclusion in the entry notes, with the reason - the chain rests on the structurally resolved site-3 mechanism and adding the others would mean asserting a chain the cited sources do not resolve. - S4 uncited caches: six of the seven the reviewer listed are now cited. The seventh, PMID:26135709, cannot be cited: it is a Letter with content_type unavailable and no abstract in PubMed, so there is no quotable text. The reviewer suggested pruning it; it is cited by the committed deep-research report, so pruning it would break that, and the entry notes record instead that the entry does not cite it and why. The cited-PMID set was re-derived from the entry, report and sidecar immediately before this decision rather than reused from earlier in the session. An earlier draft of that notes paragraph said the cache 'has been pruned'. That was false - the re-derivation showed the report cites it - and it was corrected before commit. Prose describing repository state is content and it rots, which is exactly the case CLAUDE.md warns about. Validation: just validate-disorders passes; 123/123 snippets verified offline, up from 111. Weighted compliance 93.4%, up from 92.8%. All 19 phenotypes causally connected. Causal graph orphan_targets empty (45 nodes, 47 edges). Offline gates green: entity-refs, causal-targets, qualifier-terms, duplicate-keys, enum-values, environmental-evidence, snippet-length, title-snippets, snippet-grading, reference-titles. Every snippet verified as an exact substring before being written; every script edit asserted its anchor matched exactly once, and one of those assertions caught a wrong anchor before anything was written.

Create: Scorpion Envenomation (MONDO:0018755) · 2026-09-18T12:31:39Z · View source

New entry for scorpion envenomation, curated from a claude_code deep-research run (research/Scorpion_Envenomation-deep-research-claude_code.md, 257.89s, 23 web searches, 62 citations). Disease choice and duplicate preflight. The first candidate was lathyrism; the Step 1 preflight found it already curated and merged (PR #4213, June 2026) and it was dropped before any work was done. A second pass enumerated the 72 MONDO descendants of MONDO:0029000 poisoning against every MONDO CURIE referenced anywhere in kb/, which left 44 unused; scorpion envenomation was chosen from that list. Preflight on the chosen disease: no kb/ or stubs/ file, no PR and no issue naming scorpion or MONDO:0018755. The only related entry is Snakebite_Envenoming, which is a sibling rather than an overlap. Report validation. Reference validation was clean - 47/47 references resolved, confabulation_rate 0.0. Term validation set needs_review: true, and the four mislabelled terms split into two harmless and two seriously wrong. The harmless two were HP:0001649 and HP:0001662, where the report had prefixed the ontology labels ("Sympathetic predominance: tachycardia"). The wrong two were CL:0011105, offered as "parasympathetic neuron" and actually dopamanergic interplexiform cell, and UBERON:0001911, offered as "skin of body - sting site" and actually mammary gland. A third was caught by reading rather than by the validator: HP:0031297 was offered as "Skin ulcer" but is an obsolete coronary sinus atrial septal defect term, replaced by HP:0011643; the real Skin ulcer is HP:0200042. None of the report's suggested CURIEs was used. Every binding in the entry was looked up independently against OLS or the pinned local ECTO build at the moment it was written. preflight-dr returned SKIP, as expected for a disease MONDO records no causal gene for, so disease identity was checked by hand against the report's Section 1: it names MONDO:0018755, ICD-10-CM T63.2, MeSH Scorpion Stings, and describes buthid envenomation throughout. No Named Entity Confusion. Content: ten pathophysiology nodes in one chain with two branches and a parallel hypothesis arm. The spine runs venom neurotoxin binding at the sodium-channel voltage sensor -> loss of fast inactivation and repetitive firing -> autonomic neurotransmitter storm -> catecholamine-mediated myocardial injury -> cardiac dysfunction and pulmonary oedema. The storm node fans out to eight symptom phenotypes, each cited to a sentence that names which transmitter produces it. Sixteen phenotypes, all sixteen causally connected. The entry's substantive argument is that two accounts of what kills are on the table and they prescribe differently, so both are curated as mechanistic_hypotheses with edges opting in via hypothesis_groups. adrenergic_catecholamine_storm (CANONICAL) is the classical adrenergic myocarditis account, supported by human clinical review and by prazosin's measured benefit. il1r_pge2_cholinergic_axis (EMERGING) is PMID:33116136, in which IL-1R signalling drives PGE2, PGE2 drives excessive vagal acetylcholine, and that cholinergic arm causes the heart failure - with IL-1R knockout, dexamethasone, atropine and vagotomy each abolishing mortality in mice, and the authors noting the pathway is untouched by antivenom. Status is EMERGING rather than ALTERNATIVE because nothing in it has been tested in humans. That claim is also curated as a HUMAN_MODEL_MISMATCH rather than a knowledge gap, on the distinction CLAUDE.md draws: the evidence is not absent, it exists and is good, and what is open is whether it transfers. The discussion records three specific reasons to hold it open - an intraperitoneal bolus is not a sting, Tityus serrulatus is not the genus causing most of the world's mortality, and the only human data are correlational (PMID:41327440, cited INDIRECT for exactly that reason). A second discussion, which_autonomic_arm_kills, records the disagreement itself and notes that the two bodies of evidence are asymmetric in kind, so neither could refute the other. has_subtypes splits Neurotoxic (Buthidae) from Cytotoxic (Hemiscorpius lepturus) because these are two mechanisms, not one spectrum: PMID:9679690 reports that buthid venom is neurotropic and noncytotoxic and induces no cutaneous reaction at all, while HL venom is cytolytic. The cytotoxic branch has its own chain - phospholipase activity -> intravascular haemolysis with acquired ADAMTS13 deficiency -> thrombotic microangiopathy and acute kidney injury - and shares none of the autonomic nodes. Every phenotype carries a subtype key. conforms_to: the IL-1R node declares nlrp3_inflammasome_activation#NLRP3 Inflammasome Assembly and Caspase-1 Activation, which the source supports directly - it reports NLRP3-, ASC- and caspase-1-dependent IL-1 beta release after venom. No conformance was declared to any cardiac module: cardiac_ion_channel_repolarization scopes itself to inherited arrhythmia syndromes in structurally normal hearts, which this is not. Ontology decisions worth recording. GO:0005248 voltage-gated sodium channel activity carries modifier GAIN_OF_FUNCTION rather than INCREASED, because the claim is qualitative - the gate that terminates channel opening has been disabled by a bound peptide - and there is no host variant, so nothing for functional_impact_category to describe. An earlier draft bound GO:0035725 in molecular_functions and failed the MolecularFunctionTerm enum, correctly: it is a biological process. ECTO has no scorpion, venom, arthropod, bite or sting class. The neurotoxic exposure binds ECTO:0000730 exposure to neurotoxin, anchored on CHEBI:50910, and the cytotoxic one binds the broader ECTO:0000537 exposure to toxin because its agent is a cytolytic enzyme rather than a neurotoxin. Six searches and their outputs are written verbatim into the exposures' notes, including the two substring false positives that 'l~sting' returns, so the next curator re-runs them rather than guessing. Neither term is flagged Not4Curation. NCIT has no generic antivenom class - OLS q=antivenom and q=antivenin against ncit each return only NCIT:C87794, a coral-snake product - so the antivenom treatment binds the generic NCIT:C15986, matching what the sibling Snakebite_Envenoming entry does, with the searches recorded. HPO has no sting-specific term either; HP:0020014 Local paresthesia at bite site is worded for a bite and the specificity is carried in preferred_term, with q=sting and q=envenomation against hp recorded as returning nothing usable. One edge is deliberately INDIRECT_UNKNOWN_INTERMEDIATES: the local pain edge. The source attributes the pain to venom penetration without naming the receptor or afferent population, and the obvious candidate - the same sodium-channel action on nociceptors - is not what the sentence says, so the intermediates are recorded as unknown rather than assumed. Sources refused. The report cited Medscape, Wikidata, icd10data.com, a UN guidance PDF and several journal landing pages. None was used. Where such a passage named a real finding a peer-reviewed source was located for it instead - the seven risk regions and the 2.3 billion denominator came from PMID:18579104, the severity grading from PMID:37902581. References: 18 distinct (16 literature plus the NCT and ICTRP trial registrations), all cited with exact quotes. PMC identifiers in the report were resolved to PMIDs through the NCBI converter before fetching, and DOIs to PMIDs through esearch, so PMID-keyed evidence is used throughout rather than the DOI-keyed form the validator skips. One fetched cache was pruned (PMID_21876146, the same PNAS paper the report cites by DOI and which the entry does not cite); the cited set was re-derived immediately before pruning and no orphans remain. Red-team review before PR. A subagent reviewed the entry with fresh context against the dismech-pr-review skill and returned one CRITICAL and ten IMPORTANT findings; all were verified independently against the caches and ontologies before being acted on, and all were fixed in this same session before any commit. The CRITICAL one is worth recording in full because it is the failure mode the repo's own guidance names. The NLRP3 conformance evidence had been quoted as "TsV increased NLRP3, Asc, and Casp1/11" - truncated mid-clause. The source reads "TsV increased NLRP3, Asc, and Casp1/11-dependent IL-1 beta release": those three names qualify "dependent", so the paper says release REQUIRED the inflammasome components. As truncated, the snippet asserted instead that venom upregulated them - which is transcript-upregulation evidence, exactly what the NLRP3 module's node description excludes as insufficient for conformance. Worse, the explanation justified the truncation by claiming the full clause could not be quoted because of a superscript; that was false. The full clause is an exact substring, the character between "11" and "dependent" being U+2212 MINUS SIGN rather than a hyphen. Fixed by quoting the full clause and removing the false justification. Every gate passed in both states, which is the point: nothing in the stack reads which claim a true quote is attached to. Other findings fixed: three storm-to-symptom edges (hyperhidrosis, vomiting, priapism) cited a transmitter-mapping sentence that does not name them, and were re-cited to sources that do; six quote_role values on PMID:37902581 were REVIEW_SYNTHESIS when that paper's publication_types is Journal Article only and the quotes come from its introduction, so they are now BACKGROUND; PMID:41327440 was graded HUMAN_CLINICAL on a sentence that describes animal studies and is now MODEL_ORGANISM, with a second item added for its actual human result; the discussion prose claimed IL-1 beta tracks with cardiac AND pancreatic complications when that study found the pancreatic association insignificant, and now says so; CL:0000166 chromaffin cell was replaced by the exact CL:0000336 adrenal medulla chromaffin cell; HP:0002307 Drooling was replaced by HP:0003781 Excessive salivation, which is the secretory-drive concept the mechanism claims rather than the orofacial-overflow one; two ADAMTS13 evidence items were moved onto the sentences that state their claims; a node named Cytotoxic Venom Phospholipase Activity asserted an enzymology nothing cited supports and was renamed Cytolytic Venom Membrane Damage with the reason recorded; and an edge whose own description said the inflammatory arm runs in parallel was drawn from the storm node anyway, and is now drawn from the exposure so the graph says what the curation says. Process note worth recording. Two evidence additions earlier in the session printed success while silently doing nothing, because the edits used str.replace without asserting the anchor matched. They were caught only by reading the compliance breakdown, which showed the canonical hypothesis and one discussion at zero evidence. Every subsequent edit asserts its anchor count. Content added in the review round, against the skill's Content-Completeness Checklist: an animal_models entry for the C57BL/6 Tityus serrulatus model, with three typed ModelMechanismLinks carrying fidelity, model_scale, readouts, limitations and SPECIES_MISMATCH / BOUNDARY_OMISSION divergences. This matters because the entire EMERGING hypothesis and four pathophysiology nodes rest on that one model, and the translational caveats were previously trapped in discussion prose where nothing can query them. Also added: a clinical_trials block carrying NCT00685230 (the Boyer trial) and CTRI/2013/09/004002 via its WHO ICTRP record, which is the non-ClinicalTrials.gov registry case CLAUDE.md documents - fetched with just ictrp-fetch, and its retrospective registration quoted rather than asserted because it bears on how the result reads. A second prevalence record carries a real rate with its denominator (70 per 100,000 inhabitant-years, Brazil) alongside the worldwide count. Deliberately not done, and why. There is no datasets block: the disease has no disease-specific omics resource in the report, and a GEO search on scorpion venom returns venom-gland transcriptomes of the animal rather than host-response data, which is the Named Entity Confusion case CLAUDE.md describes reached through dataset search. Several phenotypes the report describes (pancreatitis, stroke, the neuromuscular hyperexcitability cluster) and several treatments (atropine, levosimendan, nanobody antivenoms) are left out of this first pass rather than curated thinly; the cached sources for them are committed, so the next round has them to hand. Validation on the pushed tree: just validate-disorders passes; 85/85 snippets verified offline against the committed cache; weighted compliance 91.4%; phenotype connectivity 16/16 (100%). just check-genereviews returns NO_CHAPTER for both Bookshelf collections, which the entry's notes record and which is expected for an acquired envenomation. just model-scale-audit does not flag this entry. Full pytest tests/test_data.py: 6806 passed. Offline gates green: duplicate-keys, entity-refs, causal-targets, qualifier-terms, title-snippets, snippet-length, snippet-grading, enum-values, folded-hyphens, environmental-evidence, reference-titles, not4curation.

Claude Code ▸

Scorpion Envenomation — Comprehensive Research Report

claude-haiku-4-5-20251001, claude-sonnet-5 62 citations 2026-09-18T12:00:21.036662

Scorpion Envenomation — Comprehensive Research Report

1. Disease Information

Overview. Scorpion envenomation is the clinical syndrome produced by injection of venom through the telson (stinger) of a scorpion, ranging from a trivial local sting to a life-threatening toxicological emergency dominated by autonomic "storm," neuromuscular hyperexcitability, and cardiopulmonary collapse. Of more than 2,900 described scorpion species, roughly 100 (nearly all in family Buthidae) are of medical significance (Medscape/eMedicine overview; PMC8158070 "Neurological and Systemic Manifestations of Severe Scorpion Envenomation"). It is classified by WHO among the neglected tropical diseases of high public-health relevance in endemic regions (PMC12170520, "Scorpionism: a neglected tropical disease with global public health implications," 2025).

Key identifiers. - MONDO: MONDO:0018755 (scorpion envenomation; "has cause: scorpion sting") - ICD-10-CM: T63.2 (Toxic effect of venom of scorpion), with subcodes T63.2X1– (accidental), T63.2X3– (assault), T63.2X4– (undetermined) - MeSH: "Scorpion Stings" (D012620) - Note: this is an injury/toxicological entry rather than a classical Mendelian or complex genetic disease — OMIM/Orphanet do not carry a disease record for it (consistent with the "Injury" category assigned to this stub).

Synonyms/alternative names: scorpionism, scorpion sting, scorpion stinging, scorpion poisoning, scorpion toxicosis (veterinary literature).

Evidence basis. Information is derived overwhelmingly from aggregated clinical/epidemiologic case series, hospital cohorts, and national poison-control/registry data (Mexico, Brazil, Iran, Tunisia, Morocco, India) rather than individual-patient EHR mining, supplemented by controlled clinical trials of antivenom and toxin-mechanism studies in animal/cell models.

Sources: Scorpion Envenomation – Medscape · Neurological and Systemic Manifestations of Severe Scorpion Envenomation – PMC8158070 · Scorpionism: a neglected tropical disease – PMC12170520 · scorpion envenomation – Wikidata Q55788313 · ICD-10 T63.2X1A – icd10data.com

2. Etiology

Disease causal factor: direct envenomation — injection of a complex peptide/protein venom through the scorpion telson. This is a mechanistic/toxicological (not genetic) etiology; there is no host causal gene. All "risk factors" below are risk factors for exposure or for severity of envenomation, not for genetic disease susceptibility per se.

Genetic risk/modifier factors (host side): None established as disease-causing loci. The closest analogues in the literature are (a) age-dependent physiologic vulnerability (smaller body mass, immature autonomic/cardiovascular reserve in children) rather than a genotype, and (b) individual "sensitivity to venom" invoked qualitatively by Ministry of Health severity models without a defined genetic marker (PMC10615126, "Moderate or severe scorpion sting: identification of risk factors").

Environmental/exposure risk factors: - Geography — seven historically recognized high-risk regions: North Saharan Africa, Sahelian Africa, southern Africa, Near/Middle East, South India, Mexico, and northern South America/Amazon basin east of the Andes, covering an estimated 2.3 billion people at risk (Chippaux & Goyffon 2008, PMID:18579104, Acta Tropica 107:71-79). - Occupation — farming, agricultural labor, firewood collection, animal husbandry (handling ducks/hens), and rural residence. - Housing quality — thatched roofs, cracks/crevices in walls and floors that harbor scorpions; sleeping on the floor without a bed net. - Age — children under 15, and especially under 5–10 years, are disproportionately at risk of severe/fatal envenomation because of lower body mass amplifying effective venom dose per kg (multiple sources below). - Sting location — stings on the torso, head, or neck (closer to central circulation) predict faster systemic absorption and greater severity than distal-limb stings. - Time-to-treatment — delay >3 hours between sting and antivenom/hospital care is an independent severity predictor. - Climate/behavior — scorpion activity (and sting incidence) rises with warm-season nocturnal foraging.

Protective factors (environmental): footwear use, bed nets suspended below thatched roofs, sealing of household cracks/crevices, shaking out shoes/bedding before use, improved rural healthcare access enabling rapid antivenom administration, and community education/awareness campaigns.

Gene–environment interactions: not characterized in the literature as a formal GxE model; the closest is pharmacogenomic variability in individual antivenom/catecholamine response, which remains unstudied at a population-genetic level.

Sources: Epidemiology of scorpionism: a global appraisal – PMID:18579104 · Scorpionism at the human–environment interface – PMC13006650 · Moderate or severe scorpion sting: risk factors – PMC10615126 · DHMOSH UN Guidance for Prevention/Management of Scorpion Stings

3. Phenotypes

Local phenotypes (signs)

Local pain/paresthesia at sting site — nearly universal, immediate, often severe and out of proportion to visible findings for buthid stings (HP:0012531 Pain / HP:0040218 Paresthesia). Onset: immediate. Frequency: ~99–100% for most species.
Erythema, edema, tenderness (HP:0010783 Erythema) — mild local envenomation category, estimated ~68.6% of cases.
Skin necrosis / bullae / ulceration — characteristic of cytotoxic species (Hemiscorpius lepturus), classically delayed and initially painless, evolving over days (HP:0031297 Skin ulcer). PMID:9679690 "Cutaneous manifestations of the Hemiscorpius lepturus sting."

Systemic/autonomic phenotypes

Autonomic "storm" — mixed sympathetic and parasympathetic hyperactivity: tachycardia, hypertension, diaphoresis, hypersalivation, lacrimation, vomiting (cholinergic "SLUDGE" pattern) followed often by a later parasympathetic/hypotensive phase.
Sympathetic predominance: tachycardia (HP:0001649), hypertension (HP:0000822), hyperthermia (HP:0001945), pulmonary edema (HP:0100598).
Parasympathetic predominance: bradycardia (HP:0001662), hypotension (HP:0002615), sialorrhea/hypersalivation (HP:0002307), lacrimation, priapism (HP:0030731) — reported as a Grade II severity feature in children, pathogenically linked to acetylcholine-driven parasympathetic activation.
Cardiotoxicity — arrhythmia, myocarditis, cardiogenic shock, congestive heart failure; onset can be within 2 hours of the sting. Reported mortality in confirmed scorpion myocarditis ≈7.3% (PLOS NTD systematic review, PMID:37018229).
Pulmonary edema/respiratory failure — leading proximate cause of death; occurs with or without hemoptysis in 7–32% of respiratory cases; mechanism combines direct toxin-induced increased pulmonary vascular permeability with catecholamine-driven afterload/hypoxia.
Neuromuscular hyperexcitability — fasciculations, tremor, opsoclonus/roving eye movements, trismus, dysarthria, cranial-nerve hyperactivity (HP:0001336 Myoclonus, HP:0002378 Fasciculations).
Gastrointestinal — nausea, vomiting, abdominal pain, hypersalivation, and acute pancreatitis — hyperamylasemia in ~80% of a case series, elevated immunoreactive cationic trypsin in 93% of pediatric cases after Leiurus quinquestriatus stings (PMID:2028471).
Endocrine/metabolic — stress hyperglycemia mediated by catecholamine/counter-regulatory hormone release, correlating with severity (recent 2025/2026 cohort, PMC12974955).
Hematologic/renal (cytotoxic species, e.g., Hemiscorpius lepturus) — intravascular hemolysis, disseminated intravascular coagulation, acquired ADAMTS13 deficiency, hemolytic-uremic syndrome, acute kidney injury (PMID:23893367; PMC2813541; PMC11872030).
Neurological complications (rare) — ischemic and hemorrhagic stroke, seizures, altered consciousness/coma (systematic review, PMC11403367).
Local mechanical/traumatic sequelae — massive tissue defect reconstruction case reports for severe cytotoxic necrosis.

Phenotype characteristics

Onset: typically minutes (local pain, autonomic symptoms); systemic/cardiopulmonary complications generally manifest within 1–6 hours, occasionally up to 24 hours.
Severity/frequency by grade (commonly used 3–4 tier systems):
Mild (Grade I): local pain ± paresthesia only — most common (~68.6% in one classification).
Moderate (Grade II/III): ascending local signs, mild systemic signs, sweating, vomiting, tachycardia/tachypnea, hypertension, cranial-nerve involvement, twitching (~26.8%).
Severe (Grade IV): profuse vomiting/sweating/salivation, seizures, coma, bradycardia, heart failure, severe pulmonary edema, shock — life-threatening.
Progression: typically rapid (hours) rather than chronic; most survivors resolve within 24–48 hours with or without antivenom.
Quality of life: acute, self-limited in the majority; severe cases can leave residual organ dysfunction (renal, cardiac) or, rarely, neurological deficits after stroke. Formal EQ-5D/SF-36 data specific to scorpion envenomation are not established in the literature reviewed.

Sources: Scorpion Envenomation Clinical Presentation – Medscape · Classification of clinical consequences of scorpion stings: consensus development · Neurological and Systemic Manifestations – PMC8158070 · Scorpion envenomation-associated myocarditis: systematic review – PMID:37018229 · Acute pancreatitis following Leiurus quinquestriatus envenomation – PMID:2028471 · Predictive value of admission blood glucose – PMC12974955 · Stroke as a rare complication of scorpion stings – PMC11403367 · ADAMTS13 deficiency after hemolysis – PMID:23893367 · Cutaneous manifestations of Hemiscorpius lepturus sting – PMID:9679690 · Scorpion Envenomation with Delayed Ischemic Priapism – AJTMH

4. Genetic/Molecular Information

Scorpion envenomation has no human causal gene — it is toxin-mediated, not a Mendelian disease. The relevant "genetic/molecular" content is the venom toxin side:

Venom toxin classes (the causal molecular agents): - Long-chain neurotoxins acting on voltage-gated Na⁺ channels (Nav): - α-NaTx (α-scorpion toxins, receptor site 3): bind the voltage-sensing domain IV (VSD4) of Nav channels and inhibit fast inactivation, prolonging Na⁺ current and depolarization. Structural work (cryo-EM, 3.5 Å) resolved a eukaryotic Nav channel in complex with the lethal α-toxin AaH2, showing it wedges into VSD4 and traps a deactivated gating-charge state ("Structural basis of α-scorpion toxin action on Nav channels," Science, DOI:10.1126/science.aav8573; PNAS PMID for site mapping: PMC3696675 "Modular Organization of α-Toxins"). - β-NaTx (β-scorpion toxins, receptor site 4): bind the S3b–S4 voltage-sensor paddle of domain II and shift voltage-dependence of activation to more hyperpolarized potentials, lowering the threshold for channel opening and causing repetitive/spontaneous firing (Rockefeller J Gen Physiol review of excitatory/depressant β-toxin modes). - Net physiological effect: massive, uncontrolled presynaptic neurotransmitter release (acetylcholine at parasympathetic terminals; norepinephrine/epinephrine at sympathetic terminals and adrenal medulla), producing the autonomic storm. - K⁺ channel toxins (KTx, α/β/γ/κ families): block Kv channels, further prolonging depolarization and neurotransmitter release; e.g., α-KTx4.9 from Tityus fasciolatus. - Bradykinin-potentiating peptides (BPPs) and natriuretic-like/hypotensin peptides (e.g., Tityus serrulatus Hypotensins, TsHpt) — contribute to vascular tone changes. - Enzymes: hyaluronidase (spreading factor), metalloproteinases, phospholipases. - Cytolytic/hemolytic toxins (notably Hemiscorpius lepturus): lysophospholipase D and related lytic enzymes causing cell-membrane lysis, hemolysis, and tissue necrosis — mechanistically distinct from the neurotoxic Buthidae venoms.

Nomenclature note for dismech curation: because there is no host causal gene, this section is best modeled via CHEBI (venom peptide/small-molecule mediators — e.g., acetylcholine CHEBI:15355, epinephrine CHEBI:33568, norepinephrine CHEBI:33569, prostaglandin E2 CHEBI:15551) and GO molecular function/biological process terms rather than HGNC gene bindings. The Nav1.x / Kv channel targets in the human host can be annotated with HGNC gene symbols where the specific isoform is documented (e.g., SCN9A/Nav1.7 hgnc:10598, SCN4A/Nav1.4 hgnc:10593) — the referenced study "CeII8/CeII9" toxins are isoform-selective for Nav1.7 vs Nav1.4 (PMID:20600228).

Allele frequency / somatic-germline / ACMG classification: not applicable — this is not a variant-based disease.

Modifier genes: none established; host channel isoform expression pattern (which Nav/Kv subtypes are expressed at a given synapse) determines tissue-specific toxin effect but is not itself a "modifier gene" in the ACMG sense.

Epigenetics/chromosomal abnormalities: not applicable.

Sources: Structural basis of α-scorpion toxin action on Nav channels – Science · Modular Organization of α-Toxins – PMC3696675 · Scorpion β-toxin interference with NaV channel voltage sensor – J Gen Physiol · Mapping the receptor site for α-scorpion toxins – PNAS · CeII8/CeII9 Nav1.7/Nav1.4-selective toxins – PMID:20600228 · Novel components of Tityus serrulatus venom – transcriptomic approach · Tityus serrulatus Hypotensins · Purification of neurotoxic peptides from Hemiscorpius lepturus – PMC7211352

5. Environmental Information

Environmental factor = the disease trigger itself: scorpion envenomation is, by definition, an environmentally/mechanically caused injury (ECTO/exposure framing: exposure to scorpion venom via sting). There are no separate "contributing" environmental toxins in the classic sense, though secondary environmental modifiers include: - Ambient temperature/season — scorpion activity and human outdoor/nocturnal exposure both increase in hot months, raising sting incidence. - Housing construction materials (thatch, mud-brick with crevices) enabling scorpion cohabitation with humans. - Rural/agricultural occupational exposure (see Etiology above).

Lifestyle factors: going barefoot, sleeping on the floor, not shaking out shoes/clothing before use, storing firewood/rubble near dwellings.

Infectious agents: not applicable — scorpion envenomation is not infectious, though secondary wound infection of necrotic cytotoxic lesions (e.g., from Hemiscorpius) can occur as a complication, not an etiologic agent.

Sources: Scorpionism at the human–environment interface – PMC13006650 · DHMOSH UN Guidance

6. Mechanism / Pathophysiology

Ordered causal chain

Venom injection via telson delivers a mixture of Na⁺-channel toxins (α-NaTx, β-NaTx), K⁺-channel toxins, phospholipases/hyaluronidase, and (in cytotoxic species) lytic enzymes into subcutaneous tissue → leads to local nociceptor activation (intense pain) and, for neurotoxic Buthidae venoms, rapid systemic absorption.
α-NaTx binds Nav channel VSD4 and blocks fast inactivation; β-NaTx binds Nav channel domain II voltage sensor and lowers the activation threshold → leads to prolonged Na⁺ influx and repetitive, uncontrolled action-potential firing at peripheral and autonomic nerve terminals (demonstrated structurally for AaH2-Nav complex, Science 2019).
Repetitive firing at sympathetic postganglionic terminals and the adrenal medulla → results in massive release of norepinephrine and epinephrine ("catecholamine storm") → tachycardia, hypertension, diaphoresis, hyperglycemia (via counter-regulatory hormone release), and increased myocardial oxygen demand.
Simultaneous repetitive firing at parasympathetic (cholinergic) terminals → results in acetylcholine release → bradycardia (in the later/mixed phase), hypersalivation, lacrimation, gastric hypermotility, priapism.
Catecholamine excess → leads to (a) direct catecholamine-induced myocardial injury ("adrenergic/toxic myocarditis," inflammatory infiltrate), and (b) increased myocardial O₂ demand with relative coronary hypoperfusion → myocardial ischemia — three convergent mechanisms proposed for cardiac dysfunction: adrenergic myocarditis, toxic (direct venom) myocarditis, and ischemia (PLOS NTD systematic review, PMID:37018229).
In parallel, venom (and the host inflammatory response to it) triggers IL-1 receptor signaling → induces prostaglandin E2 (PGE2) production → PGE2 drives excessive acetylcholine release at the heart via vagal efferents → causes acetylcholine-mediated cardiac dysfunction, heart failure, and death in a validated mouse model; IL-1R deficiency, dexamethasone, atropine, or vagotomy each abolish this pathway and prevent mortality (Nature Communications 2020, PMID/PMC7595177 — direct mechanistic/causal evidence, MODEL_ORGANISM).
A parallel IL-1R→nitric-oxide pathway in the pancreas has been shown to control hyperglycemia after envenomation (PMC7150851), linking the inflammatory cascade to the metabolic phenotype described in Section 3.
Direct toxin action plus catecholamine/cytokine-driven increases in pulmonary vascular permeability → leads to noncardiogenic-plus-cardiogenic pulmonary edema, the dominant proximate cause of death, sometimes with hemoptysis.
Combined cardiogenic (myocarditis/arrhythmia) and pulmonary (edema, hypoxia) failure → results in cardiogenic/cardiopulmonary shock, the terminal common pathway in fatal cases, typically within the first hours to ~24 hours after the sting.
Branch — cytotoxic (non-neurotoxic) venoms (e.g., Hemiscorpius lepturus): lysophospholipase D and other lytic enzymes directly lyse cell membranes at the sting site and systemically → leads to local dermonecrosis (initially painless) plus intravascular hemolysis, complement/coagulation activation, acquired ADAMTS13 deficiency (with autoantibody formation) → results in disseminated intravascular coagulation, thrombotic microangiopathy, and hemolytic-uremic syndrome with acute kidney injury — a mechanistically distinct downstream chain from the Nav/Kv-driven autonomic-storm pathway above.
Branch — pancreatic injury: autonomic hyperstimulation (direct cholinergic/adrenergic overactivity on acinar cells) plus possible direct venom enzymatic effects → leads to acute pancreatitis (elevated amylase/trypsinogen), contributing to abdominal pain/vomiting.
Branch — neurological: severe hypertensive surges and coagulopathy (in cytotoxic envenomation) can precipitate hemorrhagic or ischemic stroke; direct venom neuroexcitatory action can produce seizures independent of stroke.

Detail by mechanistic category

Molecular pathways: Nav/Kv channel gating cascades (not classical signaling pathways like Wnt/MAPK); downstream, IL-1R→cyclooxygenase→PGE2→muscarinic acetylcholine signaling constitutes a defined, experimentally verified pathway (Nature Comm 2020).
Cellular processes: exocytotic neurotransmitter release (GO:0007269 neurotransmission), sympathetic/parasympathetic neuron activation, cardiomyocyte injury/apoptosis-necrosis, inflammatory cytokine release, complement activation, erythrocyte lysis (cytotoxic venoms).
Protein dysfunction: the "dysfunction" is imposed on host ion channels by toxin binding (gain-of-function-like persistent activation), not intrinsic host protein misfolding.
Immune involvement: IL-1β/IL-1R–PGE2 axis is central and causally demonstrated; correlational human data link IL-1β and malondialdehyde (oxidative stress marker) to cardiac/pancreatic complication risk (PMC12670810).
Tissue damage mechanisms: catecholamine-induced myocardial injury, hypoxic/ischemic injury from pulmonary edema, direct cytolysis (Hemiscorpius), oxidative stress (elevated MDA).
Advanced/omics data: proteomic/transcriptomic venom-gland profiling (e.g., Tityus obscurus and T. serrulatus, PMID:29561852) has catalogued the toxin repertoire (Na/K channel toxins as the dominant "toxin core," alongside metalloproteinases and hyaluronidases) but there is no reported single-cell or spatial transcriptomic human host-response dataset specific to scorpion envenomation.

Suggested GO terms: GO:0086010 (membrane depolarization during action potential), GO:0001508 (action potential), GO:0007268 (chemical synaptic transmission), GO:0043473 (pigmentation — n/a), GO:0034405 (response to fluid shear stress — n/a), GO:0006954 (inflammatory response), GO:0019233 (sensory perception of pain), GO:0001516 (prostaglandin biosynthetic process), GO:0007613 (memory — n/a). Suggested CL terms: CL:0000101 (sensory neuron), CL:0011103 (sympathetic neuron), CL:0011105 (parasympathetic neuron), CL:0000746 (cardiac muscle cell), CL:0000232 (erythrocyte, for hemolytic branch), CL:0000583 (alveolar macrophage — inflammatory branch).

Sources: Interleukin-1 receptor-induced PGE2 production controls acetylcholine-mediated cardiac dysfunction and mortality – Nat Commun, PMC7595177 · IL-1R-induced NO production in the pancreas controls hyperglycemia – PMC7150851 · Scorpion envenomation-associated myocarditis: systematic review – PMID:37018229 / PLOS NTD · Cardiovascular dysfunction following severe scorpion envenomation: mechanisms – PMID:15687982 · Structural basis of α-scorpion toxin action on Nav channels – Science · Scorpion β-toxin interference with NaV channel voltage sensor – JGP · IL-1β/MDA correlation with cardiac and pancreatic complications – PMC12670810 · Proteomic/transcriptomic venom gland profiles – PMID:29561852 · High frequency of acquired ADAMTS13 deficiency – PMID:23893367

7. Anatomical Structures Affected

Organ level: - Primary: skin/subcutis (sting site), autonomic nervous system, heart, lungs. - Secondary: pancreas (pancreatitis), kidneys (AKI, especially cytotoxic species), brain (stroke, seizures — rare), eyes (periocular sting → corneal ulceration case report), genital vasculature (priapism). - Body systems: cardiovascular, respiratory, nervous (peripheral autonomic + central), endocrine/metabolic, hematologic (cytotoxic species), integumentary.

Tissue/cell level: peripheral sensory and autonomic (sympathetic and parasympathetic) neurons and nerve terminals; cardiomyocytes; pulmonary capillary endothelium (increased permeability); pancreatic acinar cells; renal tubular/glomerular endothelium (thrombotic microangiopathy in cytotoxic envenomation); erythrocytes (hemolysis).

Subcellular level: plasma-membrane voltage-gated Na⁺ and K⁺ channels (site of primary toxin action; GO Cellular Component: GO:0005248 voltage-gated sodium channel activity is a molecular function, GO:0034706 sodium channel complex is the CC term); synaptic vesicles (neurotransmitter exocytosis); mitochondria (secondary oxidative-stress injury).

Localization (UBERON): UBERON:0000948 (heart), UBERON:0002048 (lung), UBERON:0001264 (pancreas), UBERON:0002113 (kidney), UBERON:0001911 (skin of body — sting site, typically extremities), UBERON:0001021 (nerve), UBERON:0000375 (autonomic nerve — sympathetic/parasympathetic subdivisions).

Lateralization: local sting effects are unilateral/focal at the sting site; systemic effects are bilateral/generalized.

Sources: Cardiac involvement in scorpion envenomation: review · Corneal ulceration following periocular scorpion sting – PMC11199440 · Acute kidney injury and pancreatitis due to scorpion sting

8. Temporal Development

Onset: acute, occurring at any age but disproportionately in children; local pain is immediate, systemic/autonomic signs typically within 15 minutes to a few hours, cardiopulmonary complications typically within 1–24 hours.

Progression: most cases are self-limited over 24–48 hours (mild/moderate); severe envenomation can progress rapidly (hours) to cardiogenic shock, pulmonary edema, or death, particularly in young children with delayed treatment. There is no chronic/relapsing course analogous to a genetic disease, though rare chronic-relapsing pancreatitis has been reported as a late sequela in one case report from Trinidad (PMID:8687203).

Disease course pattern: acute, generally monophasic; biphasic autonomic pattern (early sympathetic surge, later parasympathetic/cholinergic phase) is well described clinically.

Critical period for intervention: the first several hours after the sting — antivenom is most effective when given early (systematic review/meta-analysis: antivenom reverses the clinical syndrome faster than no treatment; PMID:28390429), and IL-1R/PGE2 pathway blockade (dexamethasone) has been proposed for administration "very early after envenomation, even before antiserum" based on the mouse mechanistic model (PMC7595177).

Sources: Management of scorpion envenoming: systematic review and meta-analysis – PMID:28390429 · Chronic relapsing pancreatitis from scorpion sting – PMID:8687203 · Interleukin-1 receptor-induced PGE2 – PMC7595177

9. Inheritance and Population

Not a genetic/heritable disease — no inheritance pattern, penetrance, expressivity, anticipation, mosaicism, founder effect, or carrier frequency applies.

Epidemiology: - Global incidence: estimates range from ~1.2 million (Chippaux & Goyffon 2008, PMID:18579104) to ~1.5 million scorpion stings annually. - Global mortality: >3,000 deaths/year (Chippaux/Goyffon original estimate: >3,250 deaths, 0.27% case fatality across the seven at-risk regions); scorpion envenomation is described as the second leading cause of death from venomous animals after snakebite. - Regional burden: the MENA region accounts for ~42% of the global sting burden and roughly half of related mortality. High-burden countries: Mexico, Brazil, Iran, Algeria, Morocco, Tunisia, India. - Age distribution: children <15 years (especially <5–10 years) bear disproportionate morbidity/mortality. - Sex ratio: not sharply skewed in most series, though occupational exposure patterns can shift regional sex ratios (e.g., higher male exposure in agricultural work). - Geographic variant distribution: species-specific — Centruroides sculpturatus (Sonoran Desert bark scorpion) in the US Southwest/Mexico; Androctonus australis (North Africa, probably the most lethal species worldwide) and Leiurus quinquestriatus in North Africa/Middle East; Mesobuthus tamulus (Indian red scorpion) on the Indian subcontinent; Tityus serrulatus, T. bahiensis, T. obscurus, T. silvestris (Brazil/French Guiana/Amazon); Hemiscorpius lepturus (Iran, cytotoxic syndrome).

Sources: Epidemiology of scorpionism: a global appraisal – PMID:18579104 · Scorpionism: neglected tropical disease – PMC12170520 · Assessing the burden of Scorpionism in NW Iran – PMC12286322 · Epidemiological patterns in Ecuador – PMC11951006 · Distribution, biology, and management of medically relevant bark scorpions – Oxford J Integ Pest Mgmt

10. Diagnostics

Clinical diagnosis: history of sting/scorpion sighting plus characteristic local pain and, in moderate-severe cases, autonomic/neuromuscular signs; diagnosis is predominantly clinical, not laboratory-based, for triage.

Laboratory tests: - CBC (leukocytosis common), amylase/lipase (pancreatitis screening), glucose (hyperglycemia, prognostic), creatine kinase (rhabdomyolysis), renal function tests. - Cardiac biomarkers: troponin I shows limited discrimination between mild-moderate and severe groups in pediatric cohorts; NT-proBNP/proBNP is a more sensitive early predictor of pediatric cardiotoxicity, significantly elevated in severe cases at admission and at 12–24 hours (PMID:33994108; PMID:33094659). Emerging biomarkers sST2 and FABP-3 show association with LV dysfunction (sensitivity 92.3%) in a recent (2025) study ("New biomarkers in scorpion stings," PMID:39842516). - Coagulation studies, LDH, haptoglobin, ADAMTS13 activity, and Coombs testing for suspected Hemiscorpius-type hemolytic/DIC presentations.

Imaging: chest X-ray (pulmonary edema pattern), echocardiography (LV dysfunction, wall-motion abnormalities including takotsubo-like patterns; PMID:26135709 "Scorpion envenomation cardiomyopathy: a promising model for takotsubo syndrome"), cranial CT/MRI when stroke is suspected.

Electrophysiology: ECG for arrhythmia/ischemia surveillance (ST-T changes, QT prolongation reported); EEG if seizures.

Genetic testing: not applicable — no genetic test exists or is indicated for this condition.

Histopathology/biopsy: autopsy series document myocarditis (lymphocytic/catecholaminergic pattern), pulmonary edema, and occasionally pancreatic necrosis in fatal cases (PMC7551928, "Autopsy Findings in Case of Fatal Scorpion Sting: A Systematic Review").

Clinical severity/diagnostic criteria: several regionally validated classification systems (3-tier mild/moderate/severe; 4-grade systems incorporating local pain → systemic neuromuscular signs → cardiopulmonary collapse); a "Scorpion Envenomation: ICU Transfer Prediction Score" has recently been proposed (PMC13331192).

Differential diagnosis: other envenomations (spider bite, snakebite), acute abdomen/pancreatitis of other cause, myocardial infarction, sepsis, thyroid storm, pheochromocytoma crisis (given catecholamine excess phenotype), organophosphate poisoning (cholinergic overlap).

Screening: no population screening applicable; this is an acute injury, not a condition amenable to newborn/carrier screening.

Sources: The Role of ProBNP on Prognosis in Scorpion Stings – PMID:33994108 · NT-proBNP as early predictor of pediatric cardiotoxicity – PMID:33094659 · New biomarkers in scorpion stings – PMID:39842516 · Scorpion envenomation cardiomyopathy: a takotsubo model – PMID:26135709 · Autopsy findings in fatal scorpion sting – PMC7551928 · Scorpion Envenomation: ICU Transfer Prediction Score – PMC13331192 · Diagnostic value of GPX4, IL-13, periostin, thiol/disulfide balance – PMC12629928

11. Outcome/Prognosis

Mortality: overall case-fatality low (~0.27% globally per Chippaux/Goyffon), but far higher in untreated severe pediatric cases in endemic low-resource settings; confirmed myocarditis cases carry ~7.3% mortality. Pediatric ICU cohorts (e.g., Qena Governorate, Egypt) have specifically studied predictors of in-hospital mortality (PMC6779185).

Morbidity: most survivors recover fully within 24–72 hours; severe cases may have prolonged ICU stays (mechanical ventilation required in ~35% of severe respiratory-failure cases in one series) and, rarely, residual renal impairment (post-AKI, especially cytotoxic Hemiscorpius cases) or neurological deficits post-stroke.

Complications: cardiogenic shock, pulmonary edema, myocarditis/heart failure, acute pancreatitis, AKI/HUS (cytotoxic species), DIC, stroke (rare), priapism, secondary wound infection/necrosis.

Recovery potential: generally excellent with prompt supportive care ± antivenom; echocardiographic LV dysfunction (including takotsubo-pattern cardiomyopathy) is typically reversible over days to weeks.

Prognostic factors: young age (<5–10 years), delayed time-to-treatment (>3 hours), sting on torso/head/neck, elevated NT-proBNP/sST2/FABP-3, hyperglycemia at admission, species (e.g., Androctonus australis, Tityus serrulatus, Centruroides spp., Leiurus quinquestriatus associated with higher lethality than most other genera).

Sources: Scorpion envenomation-associated myocarditis: systematic review – PMID:37018229 · Predictors for Mortality in Children, Qena Governorate, Egypt – PMC6779185 · Predictive value of admission blood glucose – PMC12974955

12. Treatment

Pharmacotherapy — antivenom (specific antidote): - Species-specific F(ab′)₂ equine antivenom is first-line for moderate-severe envenomation by medically significant species. Systematic review/meta-analysis of controlled trials (PMID:28390429; PMC5385045) found antivenom against Centruroides effective in reversing the clinical syndrome faster than no antivenom (322 participants across 3 trials). - Anascorp® (Centruroides [Scorpion] Immune F(ab′)₂, equine) — FDA-approved August 4, 2011, the first US-approved scorpion antivenom (orphan drug, priority review). Pivotal RCT (Boyer et al., NEJM 2009, DOI:10.1056/NEJMoa0808455): 100% resolution of clinical syndrome within 4 hours vs. 14.3% with placebo in 15 pediatric ICU patients with clinically significant Centruroides envenomation. - Monovalent antivenom against Mesobuthus tamulus (India) combined with prazosin resolves symptoms faster than prazosin alone (mean difference ≈12.6 hours faster).

Adjunctive/symptomatic pharmacotherapy: - Prazosin (selective α1-adrenergic antagonist, CHEBI:8364) — counteracts catecholamine-mediated vasoconstriction/peripheral ischemia; established add-on for M. tamulus stings; NCIT: C15986 (Pharmacotherapy) as treatment action term, therapeutic_agent CHEBI:8364. - Dobutamine (β1-agonist inotrope) — for myocardial depression/cardiogenic shock, typical infusion 5–10 µg/kg/min (PMID:32428515, "Dobutamine in the treatment of severe scorpion envenoming"). - Atropine — for symptomatic bradycardia/excess cholinergic effects (mechanistically supported by the IL-1R/PGE2/acetylcholine pathway study, PMC7595177, where atropine or vagotomy abolished mortality in the mouse model). - Corticosteroids (dexamethasone) — proposed as very-early adjunct based on the same mechanistic model, to blunt IL-1R-driven PGE2/acetylcholine cascade; also explored in a 2024 review of "Immunosuppressive therapies in scorpion envenomation." - Levosimendan — case-report-level evidence for acute heart failure with renal impairment post-severe envenomation (PMC12360093). - Diuretics, nitroglycerin, digoxin — used adjunctively for pulmonary edema/heart failure management per clinical judgement. - Analgesics/local anesthetics — for local pain management in mild cases (most stings require only this).

Advanced therapeutics under development: - Nanobody (VHH, camelid single-domain antibody)-based antivenoms — smaller (15 kDa vs. ~100 kDa for F(ab′)₂), better tissue penetration; a camelid antibody candidate against Hemiscorpius lepturus venom has been described (PMC5395729), and recombinant scorpion-antivenom production in E. coli is an active area (2023 review, Appl Microbiol Biotechnol, DOI:10.1007/s00253-023-12578-1). - scFv/VHH recombinant fragments targeting Na⁺-channel neurotoxins are the focus of most recent pharmaceutical-development work, aiming to reduce serum-sickness risk associated with equine antivenoms.

Surgical/interventional: generally not indicated except for debridement/reconstruction of severe necrotic wounds from cytotoxic species (e.g., Hemiscorpius neck-defect reconstruction case report) or dialysis for AKI/HUS.

Supportive/critical care: cardiac monitoring, mechanical ventilation for respiratory failure (required in ~35% of severe cases in one cohort), ICU admission for grade III/IV envenomation, fluid/electrolyte management, glycemic monitoring.

Treatment algorithm: graded, severity-stratified — Grade I/mild: local care + analgesia; Grade II/moderate: antivenom ± prazosin, close monitoring; Grade III/IV/severe: antivenom + ICU-level supportive care (dobutamine, mechanical ventilation, atropine/steroids as adjuncts).

Experimental/clinical trials: NCT01599936 (Anascorp pediatric open-label trial), NCT01336660 (equine F(ab′)₂ trial, Morocco), NCT00753064 (AScVS and/or prazosin), NCT00696683 (natural history study), NCT00624078 (Anascorp treatment protocol).

Sources: Antivenom for Critically Ill Children with Neurotoxicity from Scorpion Stings – NEJM · Management of scorpion envenoming: systematic review/meta-analysis – PMID:28390429 · Dobutamine in the treatment of severe scorpion envenoming – PMID:32428515 · Emerging options for the management of scorpion stings – PMC3401053 · A camelid antibody candidate against Hemiscorpius lepturus – PMC5395729 · Production of recombinant scorpion antivenoms in E. coli – Appl Microbiol Biotechnol 2023 · Immunosuppressive therapies in scorpion envenomation – Frontiers Toxicol 2024 · Intravenous Levosimendan case report – PMC12360093 · FDA Anascorp label

13. Prevention

Primary prevention: - Footwear use outdoors/at night; shaking out shoes, clothing, and bedding before use. - Bed nets suspended beneath thatched or gapped roofing to prevent scorpions falling onto sleepers. - Sealing cracks/crevices in walls, floors, and foundations; removing woodpiles/rubble near dwellings; general household decluttering. - Community/occupational education campaigns for farmers, laborers, and rural residents (identified as most vulnerable groups).

Secondary prevention: rapid recognition and healthcare-seeking behavior; training of rural/peripheral healthcare workers in clinical recognition and immediate management, since time-to-treatment >3 hours independently predicts severity.

Tertiary prevention: ICU protocols to prevent/limit complications (mechanical ventilation readiness, cardiac monitoring, dialysis access for AKI) in endemic-region referral centers.

Immunization: no vaccine exists or is in development for scorpion envenomation (unlike some snake-antivenom vaccine research programs).

Screening/risk stratification: clinical severity-grading systems (Section 10) function as triage/risk-stratification tools rather than population screening.

Genetic counseling: not applicable.

Public health/environmental interventions: vector (scorpion) control around dwellings, improved housing construction standards, national/regional scorpion-sting surveillance and reporting systems (as increasingly implemented in Mexico, Iran, Ecuador).

Sources: Scorpionism at the human–environment interface – eco-epidemiological synthesis – PMC13006650 · DHMOSH UN Guidance for the Prevention and Management of Scorpion Stings · Scorpionism: neglected tropical disease with global public health implications – PMC12170520

14. Other Species / Natural Disease

Veterinary relevance: scorpion envenomation is a recognized cause of acute illness in domestic animals, especially dogs and cats in endemic regions. - A case report of a Tityus bahiensis sting in a small-breed dog documented pain, aggressiveness, tachypnea, tachycardia, and local erythema, resolving within 24 hours of supportive treatment (Brazil, ScienceDirect/SciELO case report). - A retrospective study of 11 dogs and 1 cat with scorpionism in Manizales, Colombia (2009–2018) found no fatalities; two severe and five moderate cases, with local pain and limb lameness as the primary presenting signs (PMID:31563524). - Death in animals, as in humans, occurs via cardiocirculatory failure and pulmonary edema. - Corneal ulceration following periocular scorpion sting has been reported (case report context; primarily human but illustrates ocular local-toxicity mechanism relevant across species) — PMC11199440.

Comparative biology: the Nav/Kv channel toxin mechanism is broadly conserved across mammals (and indeed across the arthropod prey targeted by these toxins in nature), which is why rodent (mouse, rat, guinea pig) and canine/feline models recapitulate core neuroexcitatory and cardiovascular phenotypes, though species-specific LD50 differences are substantial (e.g., toxicity of Buthus tamulus venom varies by age and species — LD50 in mice 7.2±1.35 vs. adult rats/guinea pigs 1.14±0.08, PMID:8146875).

Zoonotic potential: not applicable — scorpion envenomation is an injury, not a transmissible/zoonotic infectious disease.

Sources: Envenomation by scorpion in dog: case report · Retrospective study of scorpionism in 11 dogs and a cat, Colombia – PMID:31563524 · Toxicity of scorpion (Buthus tamulus) venom: age/species influence – PMID:8146875 · Merck Veterinary Manual: Spider and Scorpion Bites/Stings to Animals

15. Model Organisms

Rodent (mouse/rat) models are the dominant experimental system: - Mechanistic causal model: the IL-1R–PGE2–acetylcholine cardiac-dysfunction pathway was established in a mouse envenomation model, with genetic (IL-1R-knockout) and pharmacologic (dexamethasone, atropine, vagotomy) interventions each abolishing mortality — a high-fidelity, causally interrogable model of the human cardiotoxic phenotype (PMC7595177, Nat Commun 2020). - Hyperglycemia model: a parallel mouse model demonstrated an IL-1R–nitric oxide pancreatic pathway controlling venom-induced hyperglycemia (PMC7150851). - LD50/toxicity models: intraperitoneal or intracisternal venom injection in mice is the standard lethality assay across many species' venoms (e.g., Leiurus quinquestriatus IP LD50 ≈0.25–0.50 mg/kg; Hemiscorpius lepturus LD50 ≈177 µg/mouse); species- and age-dependent toxicity has been demonstrated across mice, rats, and guinea pigs (PMID:8146875). - Electrophysiology models: mouse phrenic nerve–hemidiaphragm and sciatic nerve preparations are used to study venom-induced neurotoxicity at the neuromuscular junction (e.g., Odontobuthus doriae venom studies, PMC3813362). - Cardiomyopathy model: rat/experimental models of scorpion-envenomation cardiomyopathy have been proposed as a naturally occurring analog of human takotsubo (stress) cardiomyopathy (PMID:26135709), offering a translational bridge for catecholamine-cardiotoxicity research generally. - Histopathology models: Hemiscorpius lepturus venom injected in mice reproduces the cytotoxic/hemolytic/nephrotoxic phenotype seen in human envenomation, supporting model validity for the cytotoxic-species branch of pathophysiology.

Model recapitulation vs. limitations: rodent models robustly recapitulate the acute autonomic/cardiotoxic and cytotoxic (Hemiscorpius) phenotypes and have been directly used to establish causal mechanism (not merely correlation) for the IL-1R/PGE2/acetylcholine pathway — an unusually strong (RECAPITULATES-grade) evidentiary link for a toxin-mediated syndrome. Limitations include species-dependent LD50/sensitivity differences (rodents vs. primates/humans) and the absence of validated large-animal or iPSC-cardiomyocyte models specific to this condition in the literature surveyed.

Model databases: no dedicated MGI/IMPC genetic-knockout resource exists for "scorpion envenomation" per se (it is an induced/pharmacologic model, not a genetic strain), but IL1R1-knockout mice (a standard IMPC/MGI-catalogued line) are the specific genetic tool used in the causal cardiotoxicity study above.

Sources: Interleukin-1 receptor-induced PGE2 production – PMC7595177 · IL-1R-induced NO production in the pancreas – PMC7150851 · Scorpion envenomation cardiomyopathy: takotsubo model – PMID:26135709 · Toxicity of scorpion venom influenced by age/species – PMID:8146875 · Effects of Odontobuthus doriae venom on mouse sciatic nerve – PMC3813362 · Histopathological changes induced by Hemiscorpius lepturus venom in mice

Reference Validation

Checked with linkml-reference-validator 0.2.1.

Outcome	Count
References checked	47
Resolved	47
Unresolved (possible confabulation)	0
Unverifiable	0
References weighed for topical relevance	47
On topic	27
Off topic	0

All extracted references resolved successfully.

Term Validation

Checked with linkml-term-validator 0.4.5, through the ols: adapter.

Outcome	Count
Terms checked	45
Resolved	44
Unresolved (possible confabulation)	0
Obsolete	1
Unverifiable	0
Terms whose name was checked	25
Terms named correctly	14
Terms named as a different term	4
Terms whose name is worth a second look	7

Terms the report names something else

These identifiers resolve, so nothing about them looks wrong, and the ontology calls them something unrelated to what the report calls them. That usually means the identifier is not the one the sentence needs:

HP:0001649 (1 mention) - the report calls it "Sympathetic predominance: tachycardia"; HP calls it Tachycardia
HP:0001662 (1 mention) - the report calls it "Parasympathetic predominance: bradycardia"; HP calls it Bradycardia
CL:0011105 (1 mention) - the report calls it "parasympathetic neuron"; CL calls it dopamanergic interplexiform cell
UBERON:0001911 (1 mention) - the report calls it "skin of body — sting site, typically extremities"; UBERON calls it mammary gland

Obsolete terms

These terms are real but deprecated. Citing one is not a fabrication; it does mean the report is naming something the ontology has retired:

HP:0031297 (obsolete Coronary sinus atrial septal defect) (1 mention) - replaced by HP:0011643

Terms whose name is worth a second look

The report's name for these is recognisably related to the term's own name without being one of them. A loose paraphrase reads the same way as a citation of the wrong sibling term - and so does a related synonym, which the ontology records precisely because it names something adjacent rather than the same thing - so these are listed rather than judged:

MONDO:0018755 (1 mention) - the report calls it "scorpion envenomation; "has cause: scorpion sting"; MONDO calls it scorpion envenomation
GO:0043473 (1 mention) - the report calls it "pigmentation — n/a"; GO calls it pigmentation
GO:0034405 (1 mention) - the report calls it "response to fluid shear stress — n/a"; GO calls it response to fluid shear stress
GO:0007613 (1 mention) - the report calls it "memory — n/a"; GO calls it memory
CL:0000232 (1 mention) - the report calls it "erythrocyte, for hemolytic branch"; CL calls it erythrocyte
CL:0000583 (1 mention) - the report calls it "alveolar macrophage — inflammatory branch"; CL calls it alveolar macrophage
UBERON:0000375 (1 mention) - the report calls it "autonomic nerve — sympathetic/parasympathetic subdivisions"; UBERON calls it mandibular nerve, and lists "trigeminal nerve mandibular division" among its other names

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Scorpion Envenomation — Comprehensive Research Report

1. Disease Information

2. Etiology

3. Phenotypes

Local phenotypes (signs)

Systemic/autonomic phenotypes

Phenotype characteristics

4. Genetic/Molecular Information

5. Environmental Information

6. Mechanism / Pathophysiology

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7. Anatomical Structures Affected

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13. Prevention

14. Other Species / Natural Disease

15. Model Organisms

Reference Validation

Term Validation

Terms the report names something else

Obsolete terms

Terms whose name is worth a second look