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1
Mappings
9
Pathophys.
9
Phenotypes
2
Gaps
16
Pathograph
1
Genes
6
Medical Actions
4
Differentials
1
Deep Research
🔗

Mappings

MONDO
MONDO:0015584 febrile infection-related epilepsy syndrome
skos:exactMatch MONDO
MONDO:0015584 is the febrile infection-related epilepsy syndrome concept, the febrile subgroup of NORSE.
?

Discussions and Knowledge Gaps

2
FIRES is hypothesized to be driven by an IL-1-beta/IL-6 innate-immune cytokine surge, and anakinra/tocilizumab appear more effective when started early. Does early, mechanism-targeted cytokine blockade (versus escalating anesthetics and later immunotherapy) shorten the super-refractory status epilepticus and improve chronic-phase epilepsy and cognitive outcome?
KNOWLEDGE GAP OPEN fires-il1-early-immunotherapy-window
The cytokinopathy model predicts that early IL-1/IL-6 blockade should interrupt the cascade before irreversible neuronal injury, but the evidence is largely from case series and retrospective cohorts, and the optimal timing and agent remain unestablished.
Proposed experiments
Early cytokine-blockade timing trial in FIRES
fires-early-cytokine-blockade-trial
In a multicenter FIRES registry/trial, compare time-to-resolution of super-refractory status epilepticus and chronic-phase seizure/cognitive outcomes by time from onset to initiation of IL-1/IL-6-targeted therapy.
Readouts
Status-epilepticus duration and chronic outcome versus time-to-cytokine-blockade
Show evidence (1 reference)
PMID:27770579 SUPPORT Human Clinical
"Cerebral spinal fluid analysis revealed elevated levels of proinflammatory cytokines before treatment that normalized on anakinra, suggesting a potential pathogenic role for neuroinflammation in FIRES"
Cytokine normalization on anakinra motivates testing early mechanism-targeted cytokine blockade against outcome.
Why does a common febrile illness trigger catastrophic FIRES in a previously healthy child? Is there an underlying genetic predisposition of the innate immune response (e.g., in the IL-1 pathway or other inflammasome/cytokine genes) that determines susceptibility?
KNOWLEDGE GAP OPEN fires-genetic-susceptibility
FIRES strikes previously healthy children without an identified pathogen or classic autoimmune antibody, suggesting a host-susceptibility factor. A functional deficiency of endogenous IL-1RA (IL1RN) has been demonstrated in small FIRES cohorts, but whether this is a reproducible, generalizable susceptibility signature - and how it interacts with the febrile trigger - remains open.
Proposed experiments
Host innate-immune susceptibility genomics in FIRES
fires-host-susceptibility-genomics
Perform genomic/immunogenetic profiling (e.g., IL-1 pathway and inflammasome genes) in a FIRES cohort versus controls to test for a susceptibility signature.
Readouts
Innate-immune genetic susceptibility signature
Show evidence (1 reference)
PMID:30779222 SUPPORT In Vitro
"Our findings suggest that FIRES is associated with reduced expression of intracellular IL1RA isoforms and a functional deficiency in IL1RA inhibitory activity"
An IL1RN/IL-1RA functional-deficiency signature is the leading host-susceptibility lead motivating this gap.

Pathophysiology

9
Preceding Febrile Infection Trigger
A nonspecific febrile illness (usually an upper-respiratory or gastrointestinal infection) precedes seizure onset by roughly 24 hours to two weeks in a previously healthy individual. No specific pathogen is consistently identified in the CNS, and the fever is understood as a trigger of a maladaptive immune response rather than a direct CNS infection. This node captures the single concept of the initiating febrile trigger.
Leukocyte CL:0000738
Show evidence (1 reference)
PMID:21883180 SUPPORT Human Clinical
"A preceding febrile infection had been reported in 96% of them"
In the multicenter cohort, a preceding febrile infection was reported in 96% of FIRES patients - the defining trigger.
Functional IL-1RA Deficiency (Permissive Host Factor)
A functional deficiency of endogenous interleukin-1 receptor antagonist (IL-1RA, encoded by IL1RN) is a candidate permissive host factor: with the natural brake on IL-1-beta signaling weakened, a common febrile trigger can drive unchecked IL-1-beta activity. This node captures the single concept of the "loss of the anti-inflammatory brakes" - the gene-environment convergence at the heart of the leading FIRES model - kept separate from the febrile trigger and from the downstream inflammatory activation it permits.
Leukocyte CL:0000738
Show evidence (1 reference)
PMID:30779222 SUPPORT In Vitro
"Our findings suggest that FIRES is associated with reduced expression of intracellular IL1RA isoforms and a functional deficiency in IL1RA inhibitory activity"
Functionally deficient endogenous IL-1RA activity in FIRES patient cells is the permissive "loss of brakes" host factor.
Innate Neuroinflammatory Activation
The trigger drives activation of brain-resident innate immunity - microglia and astrocytes - with inflammasome activation and production of pro-inflammatory cytokines, prominently interleukin-1-beta and interleukin-6. A genetic predisposition of the innate immune response (e.g., variation in the IL-1 pathway) is hypothesized. This node captures the single concept of the central neuroinflammatory driver.
Microglial cell CL:0000129 Astrocyte CL:0000127
Microglial cell activation GO:0001774 ↑ INCREASED Interleukin-1 beta production GO:0032611 ↑ INCREASED Interleukin-6 production GO:0032635 ↑ INCREASED
Show evidence (2 references)
PMID:27770579 SUPPORT Human Clinical
"Cerebral spinal fluid analysis revealed elevated levels of proinflammatory cytokines before treatment that normalized on anakinra, suggesting a potential pathogenic role for neuroinflammation in FIRES"
Elevated CSF proinflammatory cytokines that normalized on IL-1 blockade support a pathogenic neuroinflammatory driver in FIRES.
PMID:36871188 SUPPORT Human Clinical
"to investigate inflammation using cerebrospinal fluid (CSF) and serum cytokines/chemokines in patients with new-onset refractory status epilepticus (NORSE) to better understand the pathophysiology of NORSE"
A dedicated cytokine study of NORSE/FIRES supports inflammation as central to the pathophysiology.
Cytokine-Driven Lowering of Seizure Threshold
Interleukin-1-beta and interleukin-6 act on neurons to lower seizure threshold - enhancing NMDA-receptor-mediated excitation, impairing GABAergic inhibition, and disrupting glutamate homeostasis. This node captures the single concept of the cytokine-to-excitability link and conforms to the shared epilepsy final common pathway.
Neuron CL:0000540
Inflammatory response GO:0006954 ↑ INCREASED
Blood-Brain Barrier Dysfunction
Neuroinflammation disrupts the blood-brain barrier, which amplifies central inflammation, permits peripheral immune access, and further destabilizes neuronal excitability. This node captures the single concept of the barrier-dysfunction amplifier arm.
Astrocyte CL:0000127
Acute inflammatory response GO:0002526 ↑ INCREASED
Cortical Excitation-Inhibition Imbalance
The convergent effect of cytokine action and barrier dysfunction is a shift of cortical networks toward excitation and hypersynchrony. This node captures the single concept of the network imbalance and conforms to the shared epilepsy final common pathway.
Neuron CL:0000540
Super-Refractory Status Epilepticus
The acute phase is explosive-onset, multifocal and bilateral tonic-clonic status epilepticus that is refractory to standard antiseizure medications and frequently to anesthetic burst-suppression (super-refractory status epilepticus), often lasting weeks. This node captures the single concept of the acute catastrophic endpoint and conforms to the shared epilepsy final common pathway.
Neuron CL:0000540
Show evidence (1 reference)
PMID:21883180 SUPPORT Human Clinical
"The 77 enrolled patients presented with prolonged refractory status epilepticus"
FIRES presents acutely as prolonged refractory status epilepticus.
Neuronal Injury and Network Reorganization
Prolonged status epilepticus and sustained neuroinflammation cause excitotoxic and inflammatory neuronal injury with mesial-temporal/hippocampal involvement and progressive atrophy, establishing an epileptogenic network. This node captures the single concept of the injury/reorganization step that bridges the acute and chronic phases.
Neuron CL:0000540
Chronic Drug-Resistant Epilepsy and Neurocognitive Sequelae
In survivors, the syndrome transitions to a chronic phase of drug-resistant (usually focal/multifocal) epilepsy accompanied by cognitive impairment and behavioral difficulties. This node captures the single concept of the chronic endpoint, kept distinct from the acute status-epilepticus endpoint, and conforms to the shared epilepsy final common pathway.
Neuron CL:0000540
Show evidence (2 references)
PMID:21883180 SUPPORT Human Clinical
"Sixty-three patients (93%) had refractory epilepsy at follow-up"
In survivors, FIRES evolves into chronic refractory epilepsy (93% at follow-up in the cohort).
PMID:20813015 SUPPORT Human Clinical
"this condition may evolve into pharmacoresistant epilepsy associated with severe cognitive impairment"
FIRES evolves into pharmacoresistant epilepsy with severe cognitive impairment - the chronic-phase endpoint.

Pathograph

Use the checkboxes to hide or show graph categories. Hover nodes for evidence and cross-linked metadata.
Pathograph: causal mechanism network for Febrile Infection-Related Epilepsy Syndrome Interactive directed graph showing how pathophysiology mechanisms, phenotypes, genetic factors and variants, experimental models, environmental triggers, and treatments relate through causal and linked edges.

Phenotypes

9
Metabolism 1
Preceding Fever Fever HP:0001945
Show evidence (1 reference)
PMID:21883180 SUPPORT Human Clinical
"A preceding febrile infection had been reported in 96% of them"
A preceding febrile infection was reported in 96% of the FIRES cohort.
Nervous System 7
Focal Seizures Focal-onset seizure HP:0007359
Bilateral Tonic-Clonic Seizures Bilateral tonic-clonic seizure HP:0002069
Encephalopathy Encephalopathy HP:0001298
Cognitive Impairment Cognitive impairment HP:0100543
Show evidence (1 reference)
PMID:21883180 SUPPORT Human Clinical
"Only 12 of the 68 surviving patients (18%) retained normal cognitive level"
The great majority of FIRES survivors have cognitive impairment (only 18% retained a normal cognitive level).
Intellectual Disability Intellectual disability HP:0001249
Show evidence (1 reference)
PMID:21883180 SUPPORT Human Clinical
"Only 12 of the 68 surviving patients (18%) retained normal cognitive level"
Only 18% of survivors retained a normal cognitive level, indicating intellectual disability in the great majority.
Behavioral Abnormality Atypical behavior HP:0000708
Show evidence (1 reference)
PMID:27770579 SUPPORT Human Clinical
"behavior and memory difficulties later in childhood"
Survivors develop behavior and memory difficulties later in childhood.
Chronic Drug-Resistant Epilepsy Seizure HP:0001250
Temporal: CHRONIC
Show evidence (1 reference)
PMID:21883180 SUPPORT Human Clinical
"Sixty-three patients (93%) had refractory epilepsy at follow-up"
Survivors are left with chronic refractory epilepsy (93% at follow-up).
Other 1
Refractory Status Epilepticus Status epilepticus HP:0002133
Temporal: ACUTE
Show evidence (1 reference)
PMID:21883180 SUPPORT Human Clinical
"The 77 enrolled patients presented with prolonged refractory status epilepticus"
FIRES presents with prolonged refractory status epilepticus.
🧬

Genetic Associations

1
IL1RN
Gene: IL1RN hgnc:6000 relationship_type: SUSCEPTIBILITY variant_origin: GERMLINE
Show evidence (2 references)
PMID:30779222 SUPPORT In Vitro
"Our findings suggest that FIRES is associated with reduced expression of intracellular IL1RA isoforms and a functional deficiency in IL1RA inhibitory activity"
FIRES patients show reduced intracellular IL-1RA expression and functionally deficient IL-1RA activity, implicating IL1RN in susceptibility.
PMID:30779222 SUPPORT Human Clinical
"Levels of endogenous IL1RA and IL1β were elevated in the serum and CSF of patients with FIRES"
Endogenous IL-1RA and IL-1-beta are elevated in FIRES serum and CSF, consistent with active IL-1 pathway inflammation that outstrips the IL-1RA brake.
💊

Medical Actions

6
Anakinra (IL-1 Receptor Antagonist)
Action: Pharmacotherapy NCIT:C15986
Agent: anakinra CHEBI:231683
Anakinra, a recombinant interleukin-1 receptor antagonist, targets the IL-1-beta-driven neuroinflammation thought to underlie FIRES and is used as an early targeted immunotherapy, with reports of seizure improvement especially when started early.
Mechanism Target:
INHIBITS Innate Neuroinflammatory Activation — Anakinra blocks IL-1 receptor signaling, dampening the IL-1-beta-driven neuroinflammatory cascade.
Show evidence (2 references)
PMID:27770579 SUPPORT Human Clinical
"Anakinra was well tolerated and effective"
The first report of anakinra in FIRES found it well tolerated and effective for super-refractory status epilepticus.
PMID:27770579 SUPPORT Human Clinical
"Anakinra is a recombinant version of the human interleukin-1 receptor antagonist used to treat autoinflammatory disorders"
Anakinra's mechanism is IL-1 receptor antagonism, matching the IL-1-beta-driven neuroinflammation model of FIRES.
Tocilizumab (IL-6 Receptor Antagonist)
Action: Pharmacotherapy NCIT:C15986
Tocilizumab, an anti-interleukin-6-receptor monoclonal antibody, targets the IL-6-driven arm of the neuroinflammation and is used as a second-line immunomodulatory option in refractory NORSE/FIRES when IL-1 blockade is insufficient.
Mechanism Target:
INHIBITS Innate Neuroinflammatory Activation — Tocilizumab blocks IL-6 receptor signaling, reducing the IL-6-driven inflammatory arm.
Ketogenic Diet
Action: ketogenic diet intake Ontology label: Ketogenic Diet NCIT:C173168
The ketogenic diet is a mainstay of FIRES management and can help terminate refractory status epilepticus, with anti-seizure and anti-inflammatory effects; early initiation is often recommended.
Mechanism Target:
INHIBITS Super-Refractory Status Epilepticus — The ketogenic diet can help terminate refractory status epilepticus.
Show evidence (2 references)
PMID:20813015 SUPPORT Human Clinical
"In seven patients, KD was efficacious within 2-4 days (mean 2 days) following the onset of ketonuria"
The ketogenic diet terminated refractory status epilepticus in most FIRES patients, shortly after ketonuria onset.
PMID:21883180 SUPPORT Human Clinical
"with the possible exception of a ketogenic diet"
In the multicenter cohort, the ketogenic diet was the only modality with a possible effect on shortening the acute phase.
First-Line Immunotherapy
Action: Immunosuppressive Therapy NCIT:C15261
First-line immunotherapy - high-dose corticosteroids, intravenous immunoglobulin, and/or plasma exchange - is used acutely to suppress the presumed immune-mediated process, though responses are frequently incomplete.
Mechanism Target:
INHIBITS Innate Neuroinflammatory Activation — Broad immunosuppression aims to dampen the neuroinflammatory driver.
Show evidence (2 references)
PMID:21883180 PARTIAL Human Clinical
"intravenous immunoglobulin (IVIG, 30 patients), steroids (29 patients)"
First-line immunotherapy (IVIG, steroids) is commonly used in FIRES, although the cohort found limited evidence of efficacy for these acute-phase modalities.
PMID:35997591 SUPPORT Other
"To develop consensus-based recommendations for the management of adult and paediatric patients with NORSE/FIRES based on best evidence and experience"
International consensus recommendations exist for NORSE/FIRES management, including acute immunotherapy.
Anesthetic Burst-Suppression
Action: Pharmacotherapy NCIT:C15986
Continuous intravenous anesthetics (e.g., midazolam, barbiturates, ketamine) are used to induce burst-suppression and control the super-refractory status epilepticus in the intensive care unit; this is supportive seizure control rather than disease-modifying.
Mechanism Target:
INHIBITS Super-Refractory Status Epilepticus — Anesthetic burst-suppression suppresses ongoing status epilepticus.
Show evidence (1 reference)
PMID:21883180 SUPPORT Human Clinical
"burst-suppression coma (BSC, 46 patients)"
Anesthetic-induced burst-suppression coma was used to control the acute status epilepticus in most patients in the cohort.
Cannabidiol
Action: Pharmacotherapy NCIT:C15986
Agent: cannabidiol CHEBI:69478
Pharmaceutical-grade cannabidiol has been reported to reduce seizures in FIRES and is used as an adjunct in the chronic drug-resistant phase.
Mechanism Target:
INHIBITS Chronic Drug-Resistant Epilepsy and Neurocognitive Sequelae — Cannabidiol reduces seizure burden as an adjunctive antiseizure agent.
🔬

Biochemical Markers

1
Elevated CSF and Serum Pro-Inflammatory Cytokines (INCREASED)
Context: Elevated cerebrospinal fluid and serum pro-inflammatory cytokines - notably interleukin-1-beta, interleukin-6, and the interleukin-1 receptor antagonist (IL-1RA) - are the biochemical signature of innate-immune activation in FIRES and are being explored as a biomarker to guide immunotherapy.
Pathograph Readouts
Readout Of Innate Neuroinflammatory Activation Positive Diagnostic
Elevated CSF/serum cytokines report the active neuroinflammatory driver of FIRES.
Show evidence (2 references)
PMID:30779222 SUPPORT Human Clinical
"Levels of endogenous IL1RA and IL1β were elevated in the serum and CSF of patients with FIRES"
Endogenous IL-1RA and IL-1-beta are elevated in the serum and CSF of FIRES patients - the biochemical cytokine signature.
PMID:36871188 SUPPORT Human Clinical
"to investigate inflammation using cerebrospinal fluid (CSF) and serum cytokines/chemokines in patients with new-onset refractory status epilepticus (NORSE) to better understand the pathophysiology of NORSE"
A dedicated CSF/serum cytokine study supports the cytokine/chemokine signature in NORSE/FIRES.
🔀

Differential Diagnoses

4

Conditions with similar clinical presentations that must be differentiated from Febrile Infection-Related Epilepsy Syndrome:

New-Onset Refractory Status Epilepticus (without preceding fever) Not Yet Curated MONDO:0018199
Overlapping Features NORSE is the parent category; FIRES is specifically the subgroup with a mandatory preceding febrile infection. NORSE cases without a preceding fever, or with an identified cause, are distinguished on that basis - so FIRES is a clinical subset defined by the febrile prodrome and by exclusion of other NORSE etiologies.
Show evidence (1 reference)
PMID:29399791 SUPPORT Other
"NORSE is a clinical presentation, not a specific diagnosis, in a patient without active epilepsy or other preexisting relevant neurological disorder, with new onset of refractory status epilepticus without a clear acute or active structural, toxic or metabolic cause"
The consensus defines NORSE as the parent presentation; FIRES is its febrile subcategory, which is the basis for distinguishing them.
Overlapping Features Anti-NMDA receptor encephalitis is a leading autoimmune mimic that can cause new-onset refractory status epilepticus; it is distinguished by detection of anti-NMDAR antibodies and its characteristic psychiatric/dyskinetic prodrome, and must be excluded before diagnosing FIRES.
Herpes Simplex Encephalitis Not Yet Curated MONDO:0012521
Overlapping Features Herpes simplex (and other viral) encephalitis is a treatable infectious cause of febrile encephalopathy with seizures that must be excluded (CSF PCR, MRI) before FIRES is diagnosed, since FIRES requires the absence of an identified CNS pathogen.
Overlapping Features Dravet syndrome (SCN1A) features fever-sensitive, often prolonged seizures and status epilepticus and can enter the differential of a febrile-triggered encephalopathy; it is distinguished by earlier (infantile) onset, the characteristic evolution, and SCN1A genetic testing.
{ }

Source YAML

click to show
name: Febrile Infection-Related Epilepsy Syndrome
creation_date: "2026-07-24T00:00:00Z"
category: Complex
description: >-
  Febrile infection-related epilepsy syndrome (FIRES) is a catastrophic
  epileptic encephalopathy that strikes previously healthy school-aged children
  a few days to two weeks after a nonspecific febrile illness. It is defined as
  the subgroup of new-onset refractory status epilepticus (NORSE) that requires a
  preceding febrile infection, and it develops without an identified acute
  structural, toxic, metabolic, or infectious (CNS pathogen) cause. The leading
  mechanistic model is a disorder of innate immunity: a febrile trigger drives
  microglial/inflammasome activation and a pro-convulsant cytokine surge
  (interleukin-1-beta, interleukin-6), which - together with blood-brain barrier
  dysfunction - lowers seizure threshold and produces explosive, multifocal,
  drug-resistant status epilepticus. The illness is biphasic: an acute
  super-refractory status epilepticus phase (often requiring prolonged anesthetic
  burst-suppression) is followed, in survivors, by a chronic phase of
  drug-resistant epilepsy with cognitive and behavioral sequelae. Because the
  acute and chronic phases are mechanistically distinct endpoints of the same
  cascade, this entry keeps them as separate downstream nodes rather than
  bundling them.
parents:
- Epilepsy
- Neurological Disease
synonyms:
- FIRES
- AERRPS
- acute encephalitis with refractory repetitive partial seizures
- DESC syndrome
- devastating epileptic encephalopathy in school-aged children
disease_term:
  preferred_term: febrile infection-related epilepsy syndrome
  term:
    id: MONDO:0015584
    label: febrile infection-related epilepsy syndrome
mappings:
  mondo_mappings:
  - term:
      id: MONDO:0015584
      label: febrile infection-related epilepsy syndrome
    mapping_predicate: skos:exactMatch
    mapping_source: MONDO
    mapping_justification: >-
      MONDO:0015584 is the febrile infection-related epilepsy syndrome concept,
      the febrile subgroup of NORSE.
prevalence:
- population: Children/adolescents (Germany)
  measure_type: ANNUAL_INCIDENCE
  prevalence_class: BAND_1_9_PER_1000000
  rate_per_100000: 0.1
  notes: >-
    Orphanet cites an annual incidence on the order of 1 per 1,000,000 in
    children/adolescents. FIRES is very rare - only on the order of 100+
    well-characterized cases have been published worldwide - and ascertainment is
    difficult because the syndrome is defined clinically and by exclusion. It
    predominantly affects previously healthy school-aged children.
- population: Children/adolescents (Germany)
  measure_type: POINT_PREVALENCE
  prevalence_class: BAND_1_9_PER_100000
  rate_per_100000: 1.0
  notes: >-
    Orphanet cites a point prevalence on the order of 1 per 100,000 in
    children/adolescents (kept as a separate record from annual incidence, which
    is roughly tenfold lower, to avoid conflating the two measures).
diagnosis:
- name: Clinical Diagnosis by Consensus Criteria (Diagnosis of Exclusion)
  diagnosis_term:
    preferred_term: clinical assessment
    term:
      id: NCIT:C124351
      label: Clinical Evaluation
  description: >-
    FIRES is a clinical diagnosis made when a previously healthy person develops
    new-onset refractory status epilepticus after a preceding febrile infection
    (typically 24 hours to 2 weeks before onset), once acute structural, toxic,
    metabolic, and identifiable infectious/autoimmune causes have been excluded.
    Workup includes MRI, EEG, CSF analysis, autoimmune/paraneoplastic antibody
    panels, and infectious and metabolic studies - all of which are, by
    definition, non-diagnostic of an alternative cause.
  results: >-
    New-onset refractory status epilepticus with a documented preceding febrile
    illness and no identified alternative cause.
  evidence:
  - reference: PMID:29399791
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "FIRES is a subcategory of NORSE, applicable for all ages, that requires a prior febrile infection starting between 2 weeks and 24 hours prior to onset of refractory status epilepticus, with or without fever at onset of status epilepticus"
    explanation: >-
      The international consensus definition specifies the diagnostic criteria
      for FIRES: a NORSE presentation with a mandatory preceding febrile infection
      in the defined time window.
pathophysiology:
- name: Preceding Febrile Infection Trigger
  description: >-
    A nonspecific febrile illness (usually an upper-respiratory or
    gastrointestinal infection) precedes seizure onset by roughly 24 hours to two
    weeks in a previously healthy individual. No specific pathogen is consistently
    identified in the CNS, and the fever is understood as a trigger of a
    maladaptive immune response rather than a direct CNS infection. This node
    captures the single concept of the initiating febrile trigger.
  role: trigger
  cell_types:
  - preferred_term: Leukocyte
    term:
      id: CL:0000738
      label: leukocyte
  evidence:
  - reference: PMID:21883180
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "A preceding febrile infection had been reported in 96% of them"
    explanation: >-
      In the multicenter cohort, a preceding febrile infection was reported in
      96% of FIRES patients - the defining trigger.
  downstream:
  - target: Innate Neuroinflammatory Activation
    causal_link_type: DIRECT
    description: >-
      The febrile trigger initiates a maladaptive innate immune response in the
      CNS.
- name: Functional IL-1RA Deficiency (Permissive Host Factor)
  description: >-
    A functional deficiency of endogenous interleukin-1 receptor antagonist
    (IL-1RA, encoded by IL1RN) is a candidate permissive host factor: with the
    natural brake on IL-1-beta signaling weakened, a common febrile trigger can
    drive unchecked IL-1-beta activity. This node captures the single concept of
    the "loss of the anti-inflammatory brakes" - the gene-environment convergence
    at the heart of the leading FIRES model - kept separate from the febrile
    trigger and from the downstream inflammatory activation it permits.
  role: modifier
  cell_types:
  - preferred_term: Leukocyte
    term:
      id: CL:0000738
      label: leukocyte
  downstream:
  - target: Innate Neuroinflammatory Activation
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    description: >-
      Deficient IL-1RA braking permits unchecked IL-1-beta-driven neuroinflammatory
      activation on exposure to the febrile trigger.
  evidence:
  - reference: PMID:30779222
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: "Our findings suggest that FIRES is associated with reduced expression of intracellular IL1RA isoforms and a functional deficiency in IL1RA inhibitory activity"
    explanation: >-
      Functionally deficient endogenous IL-1RA activity in FIRES patient cells is
      the permissive "loss of brakes" host factor.
- name: Innate Neuroinflammatory Activation
  description: >-
    The trigger drives activation of brain-resident innate immunity - microglia
    and astrocytes - with inflammasome activation and production of
    pro-inflammatory cytokines, prominently interleukin-1-beta and interleukin-6.
    A genetic predisposition of the innate immune response (e.g., variation in
    the IL-1 pathway) is hypothesized. This node captures the single concept of
    the central neuroinflammatory driver.
  role: mediator
  cell_types:
  - preferred_term: Microglial cell
    term:
      id: CL:0000129
      label: microglial cell
  - preferred_term: Astrocyte
    term:
      id: CL:0000127
      label: astrocyte
  biological_processes:
  - preferred_term: Microglial cell activation
    term:
      id: GO:0001774
      label: microglial cell activation
    modifier: INCREASED
  - preferred_term: Interleukin-1 beta production
    term:
      id: GO:0032611
      label: interleukin-1 beta production
    modifier: INCREASED
  - preferred_term: Interleukin-6 production
    term:
      id: GO:0032635
      label: interleukin-6 production
    modifier: INCREASED
  evidence:
  - reference: PMID:27770579
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Cerebral spinal fluid analysis revealed elevated levels of proinflammatory cytokines before treatment that normalized on anakinra, suggesting a potential pathogenic role for neuroinflammation in FIRES"
    explanation: >-
      Elevated CSF proinflammatory cytokines that normalized on IL-1 blockade
      support a pathogenic neuroinflammatory driver in FIRES.
  - reference: PMID:36871188
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "to investigate inflammation using cerebrospinal fluid (CSF) and serum cytokines/chemokines in patients with new-onset refractory status epilepticus (NORSE) to better understand the pathophysiology of NORSE"
    explanation: >-
      A dedicated cytokine study of NORSE/FIRES supports inflammation as central
      to the pathophysiology.
  downstream:
  - target: Cytokine-Driven Lowering of Seizure Threshold
    causal_link_type: DIRECT
    description: >-
      The cytokine surge acts on neurons to lower seizure threshold.
  - target: Blood-Brain Barrier Dysfunction
    causal_link_type: DIRECT
    description: >-
      Neuroinflammation disrupts the blood-brain barrier.
- name: Cytokine-Driven Lowering of Seizure Threshold
  description: >-
    Interleukin-1-beta and interleukin-6 act on neurons to lower seizure
    threshold - enhancing NMDA-receptor-mediated excitation, impairing GABAergic
    inhibition, and disrupting glutamate homeostasis. This node captures the
    single concept of the cytokine-to-excitability link and conforms to the
    shared epilepsy final common pathway.
  role: mediator
  conforms_to: "epilepsy_excitation_inhibition_imbalance#Ion Channel and Synaptic Dysfunction"
  cell_types:
  - preferred_term: Neuron
    term:
      id: CL:0000540
      label: neuron
  biological_processes:
  - preferred_term: Inflammatory response
    term:
      id: GO:0006954
      label: inflammatory response
    modifier: INCREASED
  downstream:
  - target: Cortical Excitation-Inhibition Imbalance
    causal_link_type: DIRECT
    description: >-
      Cytokine-driven changes shift the excitation-inhibition balance toward
      hyperexcitability.
- name: Blood-Brain Barrier Dysfunction
  description: >-
    Neuroinflammation disrupts the blood-brain barrier, which amplifies central
    inflammation, permits peripheral immune access, and further destabilizes
    neuronal excitability. This node captures the single concept of the
    barrier-dysfunction amplifier arm.
  role: mediator
  cell_types:
  - preferred_term: Astrocyte
    term:
      id: CL:0000127
      label: astrocyte
  biological_processes:
  - preferred_term: Acute inflammatory response
    term:
      id: GO:0002526
      label: acute inflammatory response
    modifier: INCREASED
  downstream:
  - target: Cortical Excitation-Inhibition Imbalance
    causal_link_type: INDIRECT_KNOWN_INTERMEDIATES
    description: >-
      Barrier breakdown amplifies the shift toward network hyperexcitability.
- name: Cortical Excitation-Inhibition Imbalance
  description: >-
    The convergent effect of cytokine action and barrier dysfunction is a shift
    of cortical networks toward excitation and hypersynchrony. This node captures
    the single concept of the network imbalance and conforms to the shared
    epilepsy final common pathway.
  role: central_effector
  conforms_to: "epilepsy_excitation_inhibition_imbalance#Excitation-Inhibition Imbalance"
  cell_types:
  - preferred_term: Neuron
    term:
      id: CL:0000540
      label: neuron
  downstream:
  - target: Super-Refractory Status Epilepticus
    causal_link_type: DIRECT
    description: >-
      Network hyperexcitability manifests as explosive, drug-resistant status
      epilepticus.
- name: Super-Refractory Status Epilepticus
  description: >-
    The acute phase is explosive-onset, multifocal and bilateral tonic-clonic
    status epilepticus that is refractory to standard antiseizure medications and
    frequently to anesthetic burst-suppression (super-refractory status
    epilepticus), often lasting weeks. This node captures the single concept of
    the acute catastrophic endpoint and conforms to the shared epilepsy final
    common pathway.
  role: consequence
  conforms_to: "epilepsy_excitation_inhibition_imbalance#Seizure Generation and Epileptogenesis"
  cell_types:
  - preferred_term: Neuron
    term:
      id: CL:0000540
      label: neuron
  evidence:
  - reference: PMID:21883180
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The 77 enrolled patients presented with prolonged refractory status epilepticus"
    explanation: >-
      FIRES presents acutely as prolonged refractory status epilepticus.
  downstream:
  - target: Neuronal Injury and Network Reorganization
    causal_link_type: DIRECT
    description: >-
      Prolonged status epilepticus and inflammation injure neurons and reorganize
      networks.
- name: Neuronal Injury and Network Reorganization
  description: >-
    Prolonged status epilepticus and sustained neuroinflammation cause
    excitotoxic and inflammatory neuronal injury with mesial-temporal/hippocampal
    involvement and progressive atrophy, establishing an epileptogenic network.
    This node captures the single concept of the injury/reorganization step that
    bridges the acute and chronic phases.
  role: mediator
  cell_types:
  - preferred_term: Neuron
    term:
      id: CL:0000540
      label: neuron
  downstream:
  - target: Chronic Drug-Resistant Epilepsy and Neurocognitive Sequelae
    causal_link_type: DIRECT
    description: >-
      The reorganized, injured network produces chronic epilepsy and cognitive
      impairment.
- name: Chronic Drug-Resistant Epilepsy and Neurocognitive Sequelae
  description: >-
    In survivors, the syndrome transitions to a chronic phase of drug-resistant
    (usually focal/multifocal) epilepsy accompanied by cognitive impairment and
    behavioral difficulties. This node captures the single concept of the chronic
    endpoint, kept distinct from the acute status-epilepticus endpoint, and
    conforms to the shared epilepsy final common pathway.
  role: consequence
  conforms_to: "epilepsy_excitation_inhibition_imbalance#Recurrent Unprovoked Seizures"
  cell_types:
  - preferred_term: Neuron
    term:
      id: CL:0000540
      label: neuron
  evidence:
  - reference: PMID:21883180
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Sixty-three patients (93%) had refractory epilepsy at follow-up"
    explanation: >-
      In survivors, FIRES evolves into chronic refractory epilepsy (93% at
      follow-up in the cohort).
  - reference: PMID:20813015
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "this condition may evolve into pharmacoresistant epilepsy associated with severe cognitive impairment"
    explanation: >-
      FIRES evolves into pharmacoresistant epilepsy with severe cognitive
      impairment - the chronic-phase endpoint.
phenotypes:
- category: Neurologic
  name: Refractory Status Epilepticus
  description: >-
    The defining acute feature is new-onset refractory status epilepticus, often
    super-refractory, with explosive multifocal and bilateral tonic-clonic
    seizures.
  phenotype_term:
    preferred_term: Status epilepticus
    term:
      id: HP:0002133
      label: Status epilepticus
    temporality: ACUTE
  evidence:
  - reference: PMID:21883180
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The 77 enrolled patients presented with prolonged refractory status epilepticus"
    explanation: >-
      FIRES presents with prolonged refractory status epilepticus.
- category: Neurologic
  name: Focal Seizures
  description: >-
    Seizures are typically multifocal, with focal-onset seizures that may become
    bilateral tonic-clonic.
  phenotype_term:
    preferred_term: Focal-onset seizure
    term:
      id: HP:0007359
      label: Focal-onset seizure
- category: Neurologic
  name: Bilateral Tonic-Clonic Seizures
  description: >-
    Focal seizures frequently evolve to bilateral tonic-clonic seizures during
    the acute phase.
  phenotype_term:
    preferred_term: Bilateral tonic-clonic seizure
    term:
      id: HP:0002069
      label: Bilateral tonic-clonic seizure
- category: Constitutional
  name: Preceding Fever
  description: >-
    A nonspecific febrile illness precedes seizure onset by roughly 24 hours to
    two weeks and is a mandatory diagnostic feature.
  phenotype_term:
    preferred_term: Fever
    term:
      id: HP:0001945
      label: Fever
  evidence:
  - reference: PMID:21883180
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "A preceding febrile infection had been reported in 96% of them"
    explanation: >-
      A preceding febrile infection was reported in 96% of the FIRES cohort.
- category: Neurologic
  name: Encephalopathy
  description: >-
    Encephalopathy accompanies the acute status epilepticus.
  phenotype_term:
    preferred_term: Encephalopathy
    term:
      id: HP:0001298
      label: Encephalopathy
- category: Neurodevelopmental
  name: Cognitive Impairment
  description: >-
    Survivors are commonly left with cognitive impairment in the chronic phase.
  phenotype_term:
    preferred_term: Cognitive impairment
    term:
      id: HP:0100543
      label: Cognitive impairment
  evidence:
  - reference: PMID:21883180
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Only 12 of the 68 surviving patients (18%) retained normal cognitive level"
    explanation: >-
      The great majority of FIRES survivors have cognitive impairment (only 18%
      retained a normal cognitive level).
- category: Neurodevelopmental
  name: Intellectual Disability
  description: >-
    Most survivors are left with intellectual disability, frequently severe; only
    a small minority retain a normal cognitive level.
  phenotype_term:
    preferred_term: Intellectual disability
    term:
      id: HP:0001249
      label: Intellectual disability
  evidence:
  - reference: PMID:21883180
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Only 12 of the 68 surviving patients (18%) retained normal cognitive level"
    explanation: >-
      Only 18% of survivors retained a normal cognitive level, indicating
      intellectual disability in the great majority.
- category: Neurodevelopmental
  name: Behavioral Abnormality
  description: >-
    Behavioral difficulties are a common part of the chronic neurodevelopmental
    sequelae in survivors.
  phenotype_term:
    preferred_term: Atypical behavior
    term:
      id: HP:0000708
      label: Atypical behavior
  evidence:
  - reference: PMID:27770579
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "behavior and memory difficulties later in childhood"
    explanation: >-
      Survivors develop behavior and memory difficulties later in childhood.
- category: Neurologic
  name: Chronic Drug-Resistant Epilepsy
  description: >-
    Survivors develop chronic drug-resistant epilepsy after the acute phase.
  phenotype_term:
    preferred_term: Seizure
    term:
      id: HP:0001250
      label: Seizure
    temporality: CHRONIC
  evidence:
  - reference: PMID:21883180
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Sixty-three patients (93%) had refractory epilepsy at follow-up"
    explanation: >-
      Survivors are left with chronic refractory epilepsy (93% at follow-up).
biochemical:
- name: Elevated CSF and Serum Pro-Inflammatory Cytokines
  presence: INCREASED
  context: >-
    Elevated cerebrospinal fluid and serum pro-inflammatory cytokines - notably
    interleukin-1-beta, interleukin-6, and the interleukin-1 receptor antagonist
    (IL-1RA) - are the biochemical signature of innate-immune activation in FIRES
    and are being explored as a biomarker to guide immunotherapy.
  readouts:
  - target: Innate Neuroinflammatory Activation
    relationship: READOUT_OF
    direction: POSITIVE
    endpoint_context: DIAGNOSTIC
    interpretation: >-
      Elevated CSF/serum cytokines report the active neuroinflammatory driver of
      FIRES.
  evidence:
  - reference: PMID:30779222
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Levels of endogenous IL1RA and IL1β were elevated in the serum and CSF of patients with FIRES"
    explanation: >-
      Endogenous IL-1RA and IL-1-beta are elevated in the serum and CSF of FIRES
      patients - the biochemical cytokine signature.
  - reference: PMID:36871188
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "to investigate inflammation using cerebrospinal fluid (CSF) and serum cytokines/chemokines in patients with new-onset refractory status epilepticus (NORSE) to better understand the pathophysiology of NORSE"
    explanation: >-
      A dedicated CSF/serum cytokine study supports the cytokine/chemokine
      signature in NORSE/FIRES.
genetic:
- name: IL1RN
  gene_term:
    preferred_term: IL1RN
    term:
      id: hgnc:6000
      label: IL1RN
  relationship_type: SUSCEPTIBILITY
  variant_origin: GERMLINE
  notes: >-
    IL1RN encodes the endogenous interleukin-1 receptor antagonist (IL-1RA), the
    natural brake on IL-1-beta signaling. FIRES is not Mendelian; this is a
    candidate host-susceptibility factor rather than an established cause. In a
    small study, an index FIRES patient carried IL1RN variants of uncertain
    significance with reduced expression of intracellular IL-1RA isoforms, and
    functionally attenuated endogenous IL-1RA activity was demonstrated in a few
    patients - suggesting a permissive "loss of the anti-inflammatory brakes"
    mechanism that may be present in only some children and that also rationalizes
    anakinra (recombinant IL-1RA) therapy.
  evidence:
  - reference: PMID:30779222
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: "Our findings suggest that FIRES is associated with reduced expression of intracellular IL1RA isoforms and a functional deficiency in IL1RA inhibitory activity"
    explanation: >-
      FIRES patients show reduced intracellular IL-1RA expression and functionally
      deficient IL-1RA activity, implicating IL1RN in susceptibility.
  - reference: PMID:30779222
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Levels of endogenous IL1RA and IL1β were elevated in the serum and CSF of patients with FIRES"
    explanation: >-
      Endogenous IL-1RA and IL-1-beta are elevated in FIRES serum and CSF,
      consistent with active IL-1 pathway inflammation that outstrips the IL-1RA
      brake.
datasets: []
differential_diagnoses:
- name: New-Onset Refractory Status Epilepticus (without preceding fever)
  description: >-
    NORSE is the parent category; FIRES is specifically the subgroup with a
    mandatory preceding febrile infection. NORSE cases without a preceding fever,
    or with an identified cause, are distinguished on that basis - so FIRES is a
    clinical subset defined by the febrile prodrome and by exclusion of other
    NORSE etiologies.
  disease_term:
    preferred_term: new-onset refractory status epilepticus
    term:
      id: MONDO:0018199
      label: new-onset refractory status epilepticus
  evidence:
  - reference: PMID:29399791
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "NORSE is a clinical presentation, not a specific diagnosis, in a patient without active epilepsy or other preexisting relevant neurological disorder, with new onset of refractory status epilepticus without a clear acute or active structural, toxic or metabolic cause"
    explanation: >-
      The consensus defines NORSE as the parent presentation; FIRES is its
      febrile subcategory, which is the basis for distinguishing them.
- name: Anti-NMDA Receptor Encephalitis
  description: >-
    Anti-NMDA receptor encephalitis is a leading autoimmune mimic that can cause
    new-onset refractory status epilepticus; it is distinguished by detection of
    anti-NMDAR antibodies and its characteristic psychiatric/dyskinetic
    prodrome, and must be excluded before diagnosing FIRES.
  disease_term:
    preferred_term: anti-NMDA receptor encephalitis
    term:
      id: MONDO:0021081
      label: anti-NMDA receptor encephalitis
- name: Herpes Simplex Encephalitis
  description: >-
    Herpes simplex (and other viral) encephalitis is a treatable infectious
    cause of febrile encephalopathy with seizures that must be excluded (CSF PCR,
    MRI) before FIRES is diagnosed, since FIRES requires the absence of an
    identified CNS pathogen.
  disease_term:
    preferred_term: herpes simplex encephalitis
    term:
      id: MONDO:0012521
      label: herpes simplex encephalitis
- name: Dravet Syndrome
  description: >-
    Dravet syndrome (SCN1A) features fever-sensitive, often prolonged seizures
    and status epilepticus and can enter the differential of a febrile-triggered
    encephalopathy; it is distinguished by earlier (infantile) onset, the
    characteristic evolution, and SCN1A genetic testing.
  disease_term:
    preferred_term: Dravet syndrome
    term:
      id: MONDO:0100135
      label: Dravet syndrome
treatments:
- name: Anakinra (IL-1 Receptor Antagonist)
  description: >-
    Anakinra, a recombinant interleukin-1 receptor antagonist, targets the
    IL-1-beta-driven neuroinflammation thought to underlie FIRES and is used as an
    early targeted immunotherapy, with reports of seizure improvement especially
    when started early.
  therapeutic_modality: PROTEIN_REPLACEMENT
  target_mechanisms:
  - target: Innate Neuroinflammatory Activation
    treatment_effect: INHIBITS
    description: >-
      Anakinra blocks IL-1 receptor signaling, dampening the IL-1-beta-driven
      neuroinflammatory cascade.
  treatment_term:
    preferred_term: Pharmacotherapy
    term:
      id: NCIT:C15986
      label: Pharmacotherapy
    therapeutic_agent:
    - preferred_term: anakinra
      term:
        id: CHEBI:231683
        label: Anakinra
  evidence:
  - reference: PMID:27770579
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Anakinra was well tolerated and effective"
    explanation: >-
      The first report of anakinra in FIRES found it well tolerated and
      effective for super-refractory status epilepticus.
  - reference: PMID:27770579
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Anakinra is a recombinant version of the human interleukin-1 receptor antagonist used to treat autoinflammatory disorders"
    explanation: >-
      Anakinra's mechanism is IL-1 receptor antagonism, matching the
      IL-1-beta-driven neuroinflammation model of FIRES.
- name: Tocilizumab (IL-6 Receptor Antagonist)
  description: >-
    Tocilizumab, an anti-interleukin-6-receptor monoclonal antibody, targets the
    IL-6-driven arm of the neuroinflammation and is used as a second-line
    immunomodulatory option in refractory NORSE/FIRES when IL-1 blockade is
    insufficient.
  therapeutic_modality: MONOCLONAL_ANTIBODY
  target_mechanisms:
  - target: Innate Neuroinflammatory Activation
    treatment_effect: INHIBITS
    description: >-
      Tocilizumab blocks IL-6 receptor signaling, reducing the IL-6-driven
      inflammatory arm.
  treatment_term:
    preferred_term: Pharmacotherapy
    term:
      id: NCIT:C15986
      label: Pharmacotherapy
- name: Ketogenic Diet
  description: >-
    The ketogenic diet is a mainstay of FIRES management and can help terminate
    refractory status epilepticus, with anti-seizure and anti-inflammatory
    effects; early initiation is often recommended.
  therapeutic_modality: BEHAVIORAL
  target_mechanisms:
  - target: Super-Refractory Status Epilepticus
    treatment_effect: INHIBITS
    description: >-
      The ketogenic diet can help terminate refractory status epilepticus.
  treatment_term:
    preferred_term: ketogenic diet intake
    term:
      id: NCIT:C173168
      label: Ketogenic Diet
  evidence:
  - reference: PMID:20813015
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "In seven patients, KD was efficacious within 2-4 days (mean 2 days) following the onset of ketonuria"
    explanation: >-
      The ketogenic diet terminated refractory status epilepticus in most FIRES
      patients, shortly after ketonuria onset.
  - reference: PMID:21883180
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "with the possible exception of a ketogenic diet"
    explanation: >-
      In the multicenter cohort, the ketogenic diet was the only modality with a
      possible effect on shortening the acute phase.
- name: First-Line Immunotherapy
  description: >-
    First-line immunotherapy - high-dose corticosteroids, intravenous
    immunoglobulin, and/or plasma exchange - is used acutely to suppress the
    presumed immune-mediated process, though responses are frequently
    incomplete.
  therapeutic_modality: OTHER
  target_mechanisms:
  - target: Innate Neuroinflammatory Activation
    treatment_effect: INHIBITS
    description: >-
      Broad immunosuppression aims to dampen the neuroinflammatory driver.
  treatment_term:
    preferred_term: Immunosuppressive Therapy
    term:
      id: NCIT:C15261
      label: Immunosuppressive Therapy
  evidence:
  - reference: PMID:21883180
    supports: PARTIAL
    evidence_source: HUMAN_CLINICAL
    snippet: "intravenous immunoglobulin (IVIG, 30 patients), steroids (29 patients)"
    explanation: >-
      First-line immunotherapy (IVIG, steroids) is commonly used in FIRES,
      although the cohort found limited evidence of efficacy for these acute-phase
      modalities.
  - reference: PMID:35997591
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "To develop consensus-based recommendations for the management of adult and paediatric patients with NORSE/FIRES based on best evidence and experience"
    explanation: >-
      International consensus recommendations exist for NORSE/FIRES management,
      including acute immunotherapy.
- name: Anesthetic Burst-Suppression
  description: >-
    Continuous intravenous anesthetics (e.g., midazolam, barbiturates, ketamine)
    are used to induce burst-suppression and control the super-refractory status
    epilepticus in the intensive care unit; this is supportive seizure control
    rather than disease-modifying.
  therapeutic_modality: SMALL_MOLECULE
  target_mechanisms:
  - target: Super-Refractory Status Epilepticus
    treatment_effect: INHIBITS
    description: >-
      Anesthetic burst-suppression suppresses ongoing status epilepticus.
  treatment_term:
    preferred_term: Pharmacotherapy
    term:
      id: NCIT:C15986
      label: Pharmacotherapy
  evidence:
  - reference: PMID:21883180
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "burst-suppression coma (BSC, 46 patients)"
    explanation: >-
      Anesthetic-induced burst-suppression coma was used to control the acute
      status epilepticus in most patients in the cohort.
- name: Cannabidiol
  description: >-
    Pharmaceutical-grade cannabidiol has been reported to reduce seizures in
    FIRES and is used as an adjunct in the chronic drug-resistant phase.
  therapeutic_modality: SMALL_MOLECULE
  target_mechanisms:
  - target: Chronic Drug-Resistant Epilepsy and Neurocognitive Sequelae
    treatment_effect: INHIBITS
    description: >-
      Cannabidiol reduces seizure burden as an adjunctive antiseizure agent.
  treatment_term:
    preferred_term: Pharmacotherapy
    term:
      id: NCIT:C15986
      label: Pharmacotherapy
    therapeutic_agent:
    - preferred_term: cannabidiol
      term:
        id: CHEBI:69478
        label: cannabidiol
discussions:
- discussion_id: fires-il1-early-immunotherapy-window
  kind: KNOWLEDGE_GAP
  status: OPEN
  attaches_to:
  - "pathophysiology#Innate Neuroinflammatory Activation"
  - "pathophysiology#Super-Refractory Status Epilepticus"
  prompt: >-
    FIRES is hypothesized to be driven by an IL-1-beta/IL-6 innate-immune
    cytokine surge, and anakinra/tocilizumab appear more effective when started
    early. Does early, mechanism-targeted cytokine blockade (versus escalating
    anesthetics and later immunotherapy) shorten the super-refractory status
    epilepticus and improve chronic-phase epilepsy and cognitive outcome?
  rationale: >-
    The cytokinopathy model predicts that early IL-1/IL-6 blockade should
    interrupt the cascade before irreversible neuronal injury, but the evidence is
    largely from case series and retrospective cohorts, and the optimal timing and
    agent remain unestablished.
  evidence:
  - reference: PMID:27770579
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Cerebral spinal fluid analysis revealed elevated levels of proinflammatory cytokines before treatment that normalized on anakinra, suggesting a potential pathogenic role for neuroinflammation in FIRES"
    explanation: >-
      Cytokine normalization on anakinra motivates testing early
      mechanism-targeted cytokine blockade against outcome.
  proposed_experiments:
  - experiment_id: fires-early-cytokine-blockade-trial
    name: Early cytokine-blockade timing trial in FIRES
    description: >-
      In a multicenter FIRES registry/trial, compare time-to-resolution of
      super-refractory status epilepticus and chronic-phase seizure/cognitive
      outcomes by time from onset to initiation of IL-1/IL-6-targeted therapy.
    readouts:
    - name: Status-epilepticus duration and chronic outcome versus time-to-cytokine-blockade
      target: "pathophysiology#Super-Refractory Status Epilepticus"
    would_support:
    - "pathophysiology#Innate Neuroinflammatory Activation"
- discussion_id: fires-genetic-susceptibility
  kind: KNOWLEDGE_GAP
  status: OPEN
  attaches_to:
  - "pathophysiology#Innate Neuroinflammatory Activation"
  prompt: >-
    Why does a common febrile illness trigger catastrophic FIRES in a previously
    healthy child? Is there an underlying genetic predisposition of the innate
    immune response (e.g., in the IL-1 pathway or other inflammasome/cytokine
    genes) that determines susceptibility?
  rationale: >-
    FIRES strikes previously healthy children without an identified pathogen or
    classic autoimmune antibody, suggesting a host-susceptibility factor. A
    functional deficiency of endogenous IL-1RA (IL1RN) has been demonstrated in
    small FIRES cohorts, but whether this is a reproducible, generalizable
    susceptibility signature - and how it interacts with the febrile trigger -
    remains open.
  evidence:
  - reference: PMID:30779222
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: "Our findings suggest that FIRES is associated with reduced expression of intracellular IL1RA isoforms and a functional deficiency in IL1RA inhibitory activity"
    explanation: >-
      An IL1RN/IL-1RA functional-deficiency signature is the leading
      host-susceptibility lead motivating this gap.
  proposed_experiments:
  - experiment_id: fires-host-susceptibility-genomics
    name: Host innate-immune susceptibility genomics in FIRES
    description: >-
      Perform genomic/immunogenetic profiling (e.g., IL-1 pathway and
      inflammasome genes) in a FIRES cohort versus controls to test for a
      susceptibility signature.
    readouts:
    - name: Innate-immune genetic susceptibility signature
      target: "pathophysiology#Innate Neuroinflammatory Activation"
    would_support:
    - "pathophysiology#Innate Neuroinflammatory Activation"
📚

References & Deep Research

Deep Research

1
Claude Code
1. Disease Information
claude-haiku-4-5-20251001, claude-opus-4-8 19 citations 2026-07-24T08:16:29.109515

1. Disease Information

FIRES is a rare, catastrophic epileptic encephalopathy in which a previously healthy person — usually a school-age child — develops explosive, drug-resistant status epilepticus a few days after a banal, self-limited febrile illness (a cold, a stomach bug). The fever itself is gone or fading by the time the brain catches fire. There's no tumor, no stroke, no obvious infection in the brain, no metabolic crash to explain it. The seizures just won't stop, often for weeks to months, and survivors are almost always left with lasting epilepsy and cognitive damage.

The clean way to think about the naming, settled by the 2018 international consensus (Hirsch et al., Epilepsia 2018;59:739–744, doi:10.1111/epi.14016, verify PMID):

  • NORSE (New-Onset Refractory Status Epilepticus) is the umbrella — a clinical presentation, not a diagnosis: refractory SE with no readily identifiable acute structural, toxic, or metabolic cause, in someone without active epilepsy or a relevant prior neurological disorder.
  • FIRES is the subtype of NORSE that requires a preceding febrile infection, with fever starting between 2 weeks and 24 hours before the refractory SE onset. Fever need not be present at SE onset. FIRES applies to any age (the consensus deliberately removed the old pediatric-only restriction).
  • Cryptogenic NORSE/FIRES = the ~50% where no cause is found even after full workup. Most FIRES ends up here.

Quote (consensus framing, per NORSE Institute summary of Hirsch 2018): "FIRES is a subtype of NORSE that involves a prior febrile infection, with fever starting between 2 weeks and 24 hours prior to the onset of refractory status epilepticus."

Key identifiers:

System ID
MONDO MONDO:0015584
Orphanet ORPHA:163703
ICD-10 G40.5 (special epileptic syndromes)
ICD-11 8A63.Y (other specified status epilepticus)
GARD 11005
OMIM none — no Mendelian OMIM entry (consistent with its non-Mendelian nature)

Common synonyms / historical names (worth carrying as synonyms, because the older names encode obsolete assumptions): - Fever-Induced Refractory Epileptic Encephalopathy in School-age children (FIRES — the original Nabbout acronym) - Acute Encephalitis with Refractory Repetitive Partial Seizures (AERRPS, Japanese literature) - Devastating Epileptic Encephalopathy in School-age Children (DESC) - Idiopathic catastrophic epileptic encephalopathy; "new-onset cryptogenic febrile SE"

Data provenance: almost entirely disease-level aggregated from case reports and small case series — there is no large individual-patient EHR registry, and worldwide only ~on the order of 100+ well-characterized cases have been published. This scarcity is itself a load-bearing fact for every "frequency" and "prevalence" claim below.

Sources: Orphanet 163703, NORD, Hirsch 2018 consensus, Lit review PMC9756623.


2. Etiology

Causal factors — the honest answer is "unknown trigger, stereotyped response." The leading model is that a nonspecific febrile infection acts as a trigger, not a cause, unmasking a runaway innate-immune / autoinflammatory cascade in the brain. Think of the fever as the match and a primed neuroinflammatory system as the dry grass — the fire's character comes from the grass, not the match. Most likely, per Orphanet, "FIRES is an immune-inflammatory-mediated epileptic encephalopathy, with a vicious circle of inflammation and hyperexcitability."

  • Infectious triggers: many pathogens have been reported preceding FIRES (influenza, HHV-6, enteroviruses, Mycoplasma, respiratory/GI viruses), but no single organism is consistently found, and virus is generally not recoverable from CSF/brain — arguing against direct viral encephalitis and for a para-/post-infectious immune mechanism.
  • Not classic autoimmune encephalitis: neuronal autoantibodies (anti-NMDAR, etc.) are usually absent in cryptogenic FIRES; this distinguishes it from antibody-mediated NORSE, which is a separate branch of the NORSE tree.

Genetic risk factors: No causal Mendelian gene. The candidate-gene study by Appenzeller et al. (2012, Dev Med Child Neurol; PMID:23066759) explicitly showed "FIRES is not caused by SCN1A, POLG, PCDH19 mutations or rare copy number variations." What does recur is susceptibility in innate-immune / cytokine genes: - IL1RN (IL-1 receptor antagonist gene) — a VNTR allele and a risk haplotype were over-represented in FIRES patients vs controls; the index anakinra-responder carried multiple IL1RN variants with reduced intracellular IL-1RA expression (Clarkson et al. 2019, Ann Neurol; PMID:30779222). - Emerging single reports of rare de novo variants in innate-immune/microglial genes — e.g., a de novo pathogenic CSF1R variant implicating microglial dysfunction (Fisher et al. 2025, Epilepsia, doi:10.1111/epi.18538, verify PMID). These are individual leads, not established causes.

Environmental / demographic risk factors: young school age (peak ~7–10 yr), possibly slight male predominance, and simply having a recent febrile infection. No occupational/toxic exposures implicated.

Protective factors: none established genetically or environmentally. Suggestively, the IL1RN findings imply that adequate endogenous IL-1RA function is protective and its functional deficiency is permissive — an inverted-protection framing rather than a discovered protective allele.

Gene–environment interaction is arguably the core of FIRES: a permissive innate-immune genotype (e.g., low-functioning IL-1RA) + a common febrile infection → uncontrolled IL-1β-driven neuroinflammation. This G×E convergence is the single most curation-worthy mechanistic claim.

Sources: Appenzeller 2012 PMID:23066759, Clarkson 2019 PMID:30779222, "Fighting autoinflammation in FIRES" PMID:35356746, Fisher 2025 CSF1R.


3. Phenotypes

Clinical course runs in three phases (per lit review PMC9756623):

Prodromal phase — mild febrile illness (URI or GI), 1–2 days, then a symptom-free interval of 24 h–2 weeks.

Acute phase — the defining catastrophe: - Status epilepticus, refractory / super-refractory — HP:0002133 (Status epilepticus), with focal seizures with impaired awareness (HP:0002384) evolving to bilateral tonic-clonic seizures (HP:0002069); often multifocal with migrating perisylvian/fronto-temporal foci. Frequency: ~100% (defining feature). - Seizures broadly — HP:0001250. Frequency: obligate. - Encephalopathy / impaired consciousness — HP:0002383 (Focal-onset) / HP:0001259 (Coma) during barbiturate suppression. Frequency: very frequent. - Fever preceding — HP:0001945. Frequency: obligate by definition (in the preceding window). - Dysautonomia (tachycardia, blood pressure lability) during ICU course — HP:0011448 (Abnormal autonomic nervous system physiology). Occasional.

Chronic phase — near-universal in survivors: - Refractory/pharmacoresistant epilepsy — HP:0011171 (Refractory status is upstream) / HP:0002197 is not right; use HP:0001250 + intractability noted; Drug-resistant epilepsy maps well to HP:0011097 (Epileptic encephalopathy) as the overarching descriptor. Per PMC9756623: "among 66 of the 68 survived, 63 of them continued to have epilepsy refractory to any type of treatment." Frequency: ~90–95% of survivors. - Intellectual disability — HP:0001249. Roughly one-third normal/borderline, one-third mild–moderate ID, one-third severe ID/vegetative. Frequency: ~66–100% of survivors. - Cognitive/memory impairment — HP:0100543 (Cognitive impairment), esp. memory impairment HP:0002354 (mesial temporal injury). Very frequent. - Language impairment / regression — HP:0002463; speech regression HP:0001344. Frequent. - Behavioral / neuropsychiatric changes — HP:0000708 (Behavioral abnormality), including autistic features, ADHD-like symptoms, mood/psychiatric sequelae. Frequent. - Motor deficits — HP:0001324 (Muscle weakness) / HP:0002071 (Abnormality of extrapyramidal motor function); spasticity/ataxia in severe cases. Variable.

Laboratory phenotype: - CSF pleocytosis — mild lymphocytic, in >50% of patients (HP:0012229, Abnormal CSF protein/cellular content). - Elevated CSF & serum pro-inflammatory cytokines/chemokines (IL-6, IL-1β, IL-1RA, IL-8, CXCL/CCL chemokines) — the biochemical signature. - Usually normal glucose, negative viral PCR/cultures, negative or nonspecific autoantibodies.

Onset/severity/progression: onset acute/explosive, pediatric predominant (but any age per consensus); severity severe essentially by definition; acute phase episodic-to-continuous SE lasting weeks–months, then a chronic, often progressive-then-static deficit. QoL impact is profound — survivors frequently need lifelong care, special education, and have high caregiver burden; no FIRES-specific validated QoL instrument exists (generic pediatric epilepsy/QOLCE tools apply).

Sources: PMC9756623, Orphanet.


4. Genetic / Molecular Information

This section is where the template's gene-centric framing mostly does not apply, and that absence is itself the finding.

  • Causal genes: none established. FIRES is not Mendelian; there is no OMIM number. Prime epilepsy candidates were formally excluded (SCN1A, POLG, PCDH19, CNVs; Appenzeller 2012, PMID:23066759).
  • Susceptibility / modifier loci:
  • IL1RN (IL-1 receptor antagonist; HGNC gene IL1RN) — risk VNTR allele + haplotype; functional deficiency of endogenous IL-1RA demonstrated. This is the strongest molecular lead. "FIRES is associated with reduced expression of intracellular IL1RA isoforms and a functional deficiency in IL1RA inhibitory activity" (Clarkson 2019, PMID:30779222).
  • Polymorphisms in other cytokine genes reported (small studies) — collectively point to genetically-tuned innate-immune reactivity, not a single locus.
  • CSF1R de novo variant — a 2025 single-case lead implicating microglia (Fisher 2025).
  • Variant classification / allele frequency / somatic vs germline: Not applicable in the ACMG/ClinVar sense — there is no recurrent pathogenic variant to classify. The IL1RN signals are germline common-variant susceptibility, characterized by association, not pathogenicity calls. gnomAD/ClinVar have no FIRES-defining variant.
  • Epigenetics / chromosomal abnormalities: none characterized; karyotype/CMA are normal (part of the diagnostic exclusion).
  • Functional consequence framing: the operative molecular defect is a functional loss of anti-inflammatory braking (IL-1RA) rather than a coding change in a neuronal channel — a "loss of the brakes," not a "stuck accelerator."

Ontology handles: gene IL1RN; process GO:0032611 (interleukin-1 beta production), GO:0004908 (interleukin-1 receptor activity), GO:0070498 (interleukin-1-mediated signaling pathway).

Sources: Clarkson 2019 PMID:30779222, Appenzeller 2012 PMID:23066759.


5. Environmental Information

  • Infectious agents (trigger): a preceding nonspecific febrile infection is obligatory — but no consistent pathogen. Reported antecedents include respiratory and GI viral illnesses, influenza, HHV-6/HHV-7, enterovirus, adenovirus, Mycoplasma pneumoniae. Crucially, the CNS is usually culture/PCR-negative, so these are triggers of an immune response, not brain-invasive pathogens (NCBI Taxonomy is applicable only as "reported antecedent," not causal agent).
  • Toxic / occupational / pollution factors: none implicated (and toxic causes are an exclusion criterion for NORSE/FIRES).
  • Lifestyle factors: not applicable — this strikes previously healthy children with no lifestyle contribution.

The environmental story is thin by design: FIRES is defined partly by the absence of a clear structural/toxic/metabolic cause.


6. Mechanism / Pathophysiology

This is the heart of the entry and where the causal chain lives. Best current model — a self-amplifying innate-immune ↔ hyperexcitability loop:

Causal chain (upstream → downstream):

  1. Febrile infection primes the innate immune system → systemic + CNS cytokine surge. (trigger)
  2. Failure of anti-inflammatory braking — functionally deficient IL-1 receptor antagonist (IL-1RA) cannot restrain IL-1β signaling (Clarkson 2019). This is the pivotal node.
  3. Microglial and astrocyte activation (GO:0001774 microglial cell activation; GO:0048143 astrocyte activation) → local release of IL-1β, IL-6, TNF, IL-8, and chemokines (GO:0032635 IL-6 production; GO:0032611 IL-1β production).
  4. IL-1β → IL-1R1 signaling on neurons enhances excitability: potentiates NMDA-receptor currents (via Src-family kinase phosphorylation of GluN2B) and suppresses GABAergic inhibition → shifts the excitation/inhibition balance toward excitation (GO:0051968 positive regulation of synaptic transmission, glutamatergic).
  5. Blood–brain barrier breakdown — IL-6/IL-1 increase BBB permeability, letting peripheral immune cells and mediators in, further stoking inflammation (a positive-feedback door propped open).
  6. Seizures themselves drive more inflammation — seizure activity upregulates cytokines → the "vicious circle of inflammation and hyperexcitability" (Orphanet) → super-refractory status epilepticus.
  7. Downstream tissue injury — excitotoxic + inflammatory neuronal death, especially in hippocampus / mesial temporal structures and neocortex → chronic mesial temporal sclerosis, atrophy, and the permanent epilepsy + cognitive phenotype.

Supporting quotes: - "Elevated IL-6 levels in the central nervous system worsen neuroinflammation by activating microglia and astrocytes, releasing pro-inflammatory cytokines, and weakening the blood-brain barrier." - "FIRES is associated with reduced expression of intracellular IL1RA isoforms and a functional deficiency in IL1RA inhibitory activity" (Clarkson 2019, PMID:30779222).

Cell types (CL): microglial cell CL:0000129; astrocyte CL:0000127; central nervous system neuron / glutamatergic neuron CL:0000679; hippocampal pyramidal neuron; peripheral monocyte/macrophage CL:0000235 (infiltrating).

Biological processes (GO): GO:0006954 (inflammatory response); GO:0002526 (acute inflammatory response); GO:0070498 (IL-1-mediated signaling); GO:0032635/GO:0032611 (IL-6 / IL-1β production); GO:0001774 (microglial activation); GO:0060291/excitatory synaptic plasticity; GO:0007268 (chemical synaptic transmission); BBB dysfunction (GO:0043114 regulation of vascular permeability).

Immune involvement: predominantly innate/autoinflammatory (IL-1/IL-6 axis, microglia), not classic adaptive autoimmunity — antibodies usually absent. This is why IL-1 blockade (anakinra) and IL-6R blockade (tocilizumab) are mechanistically rational and empirically the most promising immunotherapies.

Molecular profiling: the reproducible signal is a CSF/serum cytokine-chemokine signature (↑IL-6, ↑IL-1RA, ↑IL-1β, ↑IL-8, ↑CXCL10, ↑CCL chemokines). No robust FIRES-specific transcriptomic/proteomic/metabolomic dataset yet — a genuine knowledge gap worth a discussions: KNOWLEDGE_GAP note.

Sources: "Fighting autoinflammation in FIRES" PMID:35356746, Clarkson 2019 PMID:30779222, IL-6 neuro review PMC11249726, NORSE immune dysregulation review.


7. Anatomical Structures Affected

  • Primary organ / system: brain / central nervous system (UBERON:0000955 brain; UBERON:0001017 CNS). Bilateral, often with fronto-temporal / perisylvian predominance initially.
  • Most consistently injured region: hippocampus / mesial temporal lobe (UBERON:0002421 hippocampal formation; UBERON:0002771 medial temporal lobe → chronic mesial temporal sclerosis). Also neocortical (frontal, temporal, insular/perisylvian; UBERON:0016525 insular cortex).
  • Chronic structural change: diffuse cerebral atrophy with ventriculomegaly (~49% of chronic cases) and bilateral hippocampal/temporal atrophy (~half) on follow-up MRI (PMC9756623).
  • Secondary organ involvement: systemic ICU complications of prolonged SE + anesthesia — respiratory (ventilator dependence, pneumonia), cardiovascular (dysautonomia, propofol-related issues), metabolic/hepatic (from ketogenic diet + anesthetics), immobility complications. These are downstream of critical illness, not primary FIRES targets.
  • Tissue/cell level: gray-matter neurons (hippocampal pyramidal, neocortical), reactive astrocytes and microglia; BBB endothelium (UBERON:0001986 endothelium) with increased permeability.
  • Subcellular (GO cellular component): synapse GO:0045202 (NMDA-receptor-bearing postsynaptic membrane, GO:0014069); microglial inflammasome machinery (cytoplasm); mitochondria in excitotoxic neurons (GO:0005739).
  • Lateralization: typically bilateral, may be asymmetric; hallmark EEG shows multifocal seizures with shifting/migrating foci across both hemispheres.

Sources: PMC9756623.


8. Temporal Development

  • Onset: acute / explosive, in a previously healthy person, 24 h–2 weeks after the febrile prodrome resolves. Peak pediatric onset ~7–10 years (any age per 2018 consensus).
  • Stages: (1) prodromal febrile illness → (2) acute refractory/super-refractory SE lasting weeks to months (the ICU phase) → (3) chronic drug-resistant epilepsy + neurocognitive sequelae, typically lifelong.
  • Progression rate: acute phase is rapid and severe; there is frequently no latent seizure-free "honeymoon" between acute and chronic phases — the epilepsy is continuous.
  • Course pattern: acute super-refractory (continuous) → chronic relapsing/refractory epilepsy that is usually static-to-slowly-progressive cognitively.
  • Remission: spontaneous remission of the acute SE can occur but is unpredictable; treatment-induced seizure reduction is the goal, rarely full seizure-freedom. Chronic epilepsy generally does not remit.
  • Critical window for intervention: strong emerging theme that early immunotherapy (first-line within ~72 h; escalate to anakinra/tocilizumab early) and early ketogenic diet improve outcomes — the therapeutic window is days, not weeks. This "treat early or lose the brain" window is a key actionable claim.

Sources: Wickstrom 2022 consensus PMID:35951466, PMC9756623.


9. Inheritance and Population

  • Epidemiology: rare. In Germany, prevalence ≈ 1/100,000 and annual incidence ≈ 1/1,000,000 in children/adolescents (Orphanet). Roughly ~100+ cases published worldwide; global data sparse.
  • For dismech Prevalence: measure_type: POINT_PREVALENCE, prevalence_class: BAND_1_9_PER_1000000 or BELOW_1_IN_1000000 depending on framing; rate_per_100000 ≈ 1.0 (prevalence) — and a separate ANNUAL_INCIDENCE record at rate_per_100000 ≈ 0.1 (1/1,000,000). Do not conflate the two.
  • Inheritance pattern: not heritable / not Mendelian. No AD/AR/X-linked/mitochondrial pattern; sporadic. Susceptibility is multifactorial with innate-immune (IL1RN) modifiers. Penetrance/expressivity/anticipation/founder/consanguinity/carrier-frequency fields are not applicable.
  • Demographics: predominantly school-age children, with reports across all ages since the consensus broadened it. Possible male predominance (modest, per case series). No strong ethnic/geographic clustering established (AERRPS literature is Japanese, likely ascertainment rather than true predisposition).

Sources: Orphanet, Dovepress prevalence/impact review.


10. Diagnostics

FIRES is fundamentally a diagnosis of exclusion + a compatible clinical picture (refractory SE after recent fever, no cause found). Consensus (Wickstrom 2022, PMID:35951466) emphasizes broad, rapid workup.

  • EEG (essential): early fronto-temporal spike-and-wave; evolving to multifocal seizures with migrating foci, diffuse delta-theta slowing; may show the extreme delta brush pattern (shared with anti-NMDAR encephalitis). Continuous EEG monitoring is mandatory to track (super-)refractory SE. (LOINC-codable; electrophysiology.)
  • MRI: often normal early (~61% normal at presentation — PMC9756623), which supports the diagnosis; later shows hippocampal T2/FLAIR signal → mesial temporal sclerosis, and progressive atrophy/ventriculomegaly. (RadLex/Radiopaedia.)
  • CSF: mild lymphocytic pleocytosis (>50%), usually normal glucose, negative infectious PCR/culture, and elevated pro-inflammatory cytokines/chemokines (research/specialty assays). Send autoimmune encephalitis antibody panel (serum + CSF) — usually negative, but must exclude antibody-mediated NORSE.
  • Blood: inflammatory markers; rule out systemic infection, HLH/macrophage-activation (ferritin, triglycerides — a reported FIRES mimic/overlap), metabolic and toxicologic causes.
  • Genetic testing: epilepsy gene panel / WES/WGS is recommended in the NORSE/FIRES workup to exclude monogenic mimics (e.g., PCDH19, POLG, SCN1A, mitochondrial disease) — not because a FIRES gene exists, but to rule out a look-alike. Mitochondrial testing where indicated. CMA/karyotype normal.
  • Differential diagnosis (must rule out): infectious/viral encephalitis; anti-NMDAR and other autoimmune encephalitides; mitochondrial encephalopathy (POLG, MELAS); genetic epileptic encephalopathies (Dravet/SCN1A, PCDH19); CNS vasculitis; toxic/metabolic SE; HLH/MAS-associated SE. FIRES's distinguishing features: normal prior development, obligate preceding fever, absence of identified cause, and the innate-cytokine signature.
  • Screening: no population screening — too rare, no biomarker with predictive value pre-onset.

Sources: Wickstrom 2022 PMID:35951466, PMC9756623.


11. Outcome / Prognosis

Blunt truth: FIRES is one of the worst outcomes in pediatric neurology.

  • Mortality: up to ~12–30% (acute-phase death, often from super-refractory SE and its ICU complications).
  • Epilepsy: near-universal in survivors — "among 66 of the 68 survived, 63 continued to have epilepsy refractory to any type of treatment" (PMC9756623). So >90% of survivors → chronic drug-resistant epilepsy.
  • Cognition: roughly a thirds distribution — ~1/3 normal-to-borderline, ~1/3 mild–moderate intellectual disability, ~1/3 severe ID / vegetative. Overall ~66–100% of survivors are left developmentally disabled (Orphanet/NORD).
  • Prognostic factors (emerging): longer/deeper barbiturate coma and longer SE duration → worse cognitive outcome; earlier immunotherapy and earlier ketogenic diet → better outcome. Higher/earlier cytokine burden may portend worse course. No validated prognostic biomarker yet.
  • Morbidity / QoL: severe — lifelong care needs, special education, motor/language deficits, behavioral/psychiatric comorbidity, and high family/caregiver burden.

Sources: Orphanet, NORD, PMC9756623.


12. Treatment

No cure; management is a two-front war — stop the seizures and cool the inflammation — with early, aggressive escalation. The 2022 international consensus (Wickstrom et al., PMID:35951466, 85 consensus statements) is the anchor.

A. Anti-seizure / anesthetic (acute SE control) - Standard SE ladder: benzodiazepines → IV ASMs (levetiracetam, valproate, phenytoin/fosphenytoin) → anesthetic/burst-suppression coma (midazolam, barbiturates/pentobarbital, ketamine, propofol). Caveat: prolonged barbiturate coma correlates with worse cognition — a therapy whose cure edges into harm. - MAXO: MAXO:0000058 (pharmacotherapy) / antiseizure pharmacotherapy; anesthesia. - Cannabidiol (Epidiolex): promising in both phases — case series of 7 children, 6/7 improved in seizure frequency/duration (Gofshteyn et al. 2017, J Child Neurol; PMID:27655472); acute-phase reports of SE resolution within days (Fetta 2023, Epilepsia Open, doi:10.1002/epi4.12740, verify PMID). CHEBI: cannabidiol CHEBI:69478. - Other ASMs reported ad hoc (cenobamate, perampanel, topiramate) in the chronic phase — anecdotal.

B. Ketogenic diet (KD) — a signature FIRES therapy - Landmark: Nabbout et al. 2010, Epilepsia (doi:10.1111/j.1528-1167.2010.02703.x, verify PMID) — 4:1 KD in 9 FIRES children, efficacious in 7, with seizure cessation 2–4 days after ketonuria / 4–6 days after diet onset. Now a recommended early adjunct (watch for propofol interaction → propofol infusion syndrome). MAXO: MAXO:0000088 (dietary intervention) / ketogenic diet.

C. Immunotherapy (mechanistically the most rational) - First-line, start within ~72 h: high-dose corticosteroids (MAXO/CHEBI corticosteroid), IVIG, and/or plasma exchange. MAXO: MAXO:0000759 (immunosuppressive therapy); plasmapheresis. - Second-line, escalate early in cryptogenic FIRES: - Anakinra (recombinant IL-1 receptor antagonist) — the most evidence-backed targeted therapy, born from the mechanism itself. First reported by Kenney-Jung et al. 2016, Ann Neurol (doi:10.1002/ana.24806, verify PMID): CSF cytokines normalized on treatment. In one series, 11/15 children had >50% seizure reduction at 1 week (PMC9756623); early use → shorter ICU stay. Long-term neuropsych outcomes can still be poor despite anakinra (Frontiers Neurol 2023). - Tocilizumab (IL-6 receptor monoclonal antibody) — effective in some anakinra-refractory cases (Stredny et al. 2020, Child Neurol Open, doi:10.1177/2329048X20979253, verify PMID); and vice versa — anakinra works in some tocilizumab-refractory cases even with normal IL-1β (Frontiers Immunol 2026). MAXO: MAXO:0000759 immunomodulation; therapeutic_modality: MONOCLONAL_ANTIBODY for tocilizumab. - Chronic-phase case series: anakinra/tocilizumab gave partial seizure reduction (20–50%) in some, no seizure-freedom (Seizure 2022, PMID:35759951). - Others (rituximab, tacrolimus, canakinumab, cyclophosphamide) — inconsistent/unclear benefit.

D. Other / experimental: vagus nerve stimulation and epilepsy surgery in selected chronic drug-resistant cases; therapeutic hypothermia (largely abandoned); intrathecal/other anti-cytokine strategies under study. Active clinical trials exist (e.g., KD for SRSE, NCT07496749 — verify) — search ClinicalTrials.gov for current anakinra/tocilizumab/KD FIRES trials.

Pharmacogenomics: none FIRES-specific; the closest thing to "genotype-guided therapy" is the conceptual match of IL-1RA-deficiency → anakinra, i.e., mechanism-guided rather than pharmacogenomic.

Sources: Wickstrom 2022 PMID:35951466, Kenney-Jung 2016, Nabbout 2010 KD, Gofshteyn 2017 CBD PMID:27655472, Anakinra long-term outcomes, Chronic-phase series PMID:35759951.


13. Prevention

Largely not applicable / not feasible — you can't screen for or vaccinate against a syndrome whose trigger is "some ordinary fever" in a genetically-unpredictable host.

  • Primary prevention: none. No way to identify at-risk children pre-onset; routine childhood vaccination reduces some febrile infections generally but isn't a FIRES-specific strategy.
  • Secondary prevention (early detection/treatment): the real lever — early recognition of NORSE/FIRES and rapid escalation to immunotherapy + KD within days is effectively "secondary prevention" of the devastating chronic phase. This is the consensus's central practical message.
  • Tertiary prevention: manage chronic epilepsy, rehab (PT/OT/speech), neuropsychology, avoid prolonged barbiturate coma, prevent ICU complications.
  • Genetic counseling / carrier / prenatal screening: not applicable — sporadic, non-Mendelian; recurrence risk to siblings is not meaningfully elevated.

Sources: Wickstrom 2022 PMID:35951466.


14. Other Species / Natural Disease

  • Taxonomy: described in humans (NCBITaxon:9606) only.
  • Natural animal disease: none reported — there is no recognized spontaneous FIRES equivalent in companion animals or wildlife (OMIA has no FIRES entry). Veterinary relevance: nil.
  • Comparative biology: the mechanistic pieces (fever → IL-1β/IL-6 neuroinflammation → seizure) are evolutionarily conserved and studied in rodent inflammation-induced seizure / epileptogenesis models, but no animal naturally develops the FIRES syndrome.
  • Zoonosis / cross-species transmission: not applicable (FIRES is not transmissible; the antecedent infections may be common human pathogens but FIRES itself is a host immune response).

15. Model Organisms

No faithful animal model of FIRES exists — a genuine translational gap, and worth a discussions: HUMAN_MODEL_MISMATCH entry rather than a claim of recapitulation.

  • Closest surrogates (mechanistic, not disease-faithful):
  • Rodent inflammation-driven seizure / epileptogenesis models — systemic or intracerebral LPS, IL-1β, or poly(I:C) to model fever/infection-triggered hyperexcitability; kainate/pilocarpine SE models with an inflammatory "second hit." These reproduce the IL-1β → NMDA-potentiation → seizure node but not the explosive, super-refractory, previously-healthy-child syndrome.
  • IL1RN-related manipulations (IL-1RA knockout / IL-1β overexpression) speak to the anti-inflammatory-braking hypothesis but are not "FIRES mice."
  • Genetic models: none purpose-built for FIRES (no causal gene to knock in). Il1rn-null mice exist for autoinflammation broadly and are conceptually relevant to the IL-1RA-deficiency hypothesis.
  • In vitro / patient-derived: patient CSF cytokine assays and cell-based IL-1R signaling assays (as in Clarkson 2019) are the main experimental system; iPSC-derived neuron/microglia co-cultures are a logical but not-yet-established avenue.
  • Model limitation (the crux): no model captures the whole-syndrome convergence — the specific human host-susceptibility + common-infection trigger + super-refractory course. Applications are limited to dissecting the cytokine-hyperexcitability loop, not the syndrome.

Resources: MGI (Il1rn, Il6 alleles), rodent SE/neuroinflammation literature.


Curation notes & flagged gaps for the dismech entry

  • Model this as an immune/inflammatory epileptic encephalopathy, not a gene disorder. The natural conforms_to target is the epilepsy convergence module — epilepsy_excitation_inhibition_imbalance#Excitation-Inhibition Imbalance — with FIRES supplying the upstream inflammatory driver (IL-1β/IL-6 → NMDA potentiation + GABA suppression) rather than a channel variant. Consider whether a dedicated neuroinflammation/autoinflammatory-seizure module is warranted; if one is ever built, FIRES + antibody-mediated NORSE would be natural conformers.
  • Pivotal node to curate: functional IL-1RA deficiency → unopposed IL-1β signaling (Clarkson 2019, PMID:30779222) — this is the mechanistic hinge and the therapeutic rationale for anakinra, so it deserves its own pathophysiology node with the anakinra treatment linked via target_mechanisms.
  • Two separate Prevalence records (point prevalence ~1/100,000 vs annual incidence ~1/1,000,000) — don't merge; different measure_type.
  • Evidence-source tagging: most treatment evidence is small HUMAN_CLINICAL case series (low N); the IL-1RA functional work is IN_VITRO cell-based assay + human samples; rodent inflammation-seizure work is MODEL_ORGANISM. Split accordingly.
  • PMIDs to verify before quoting (I could confirm the paper but not independently pin the PMID via search): Hirsch 2018 consensus (doi:10.1111/epi.14016), Kenney-Jung 2016 (doi:10.1002/ana.24806), Nabbout 2010 KD (doi:10.1111/j.1528-1167.2010.02703.x), Fetta 2023 CBD (doi:10.1002/epi4.12740), Stredny 2020 tocilizumab (doi:10.1177/2329048X20979253), Fisher 2025 CSF1R (doi:10.1111/epi.18538). Confirmed PMIDs: 30779222 (Clarkson), 35951466 (Wickstrom), 23066759 (Appenzeller), 27655472 (Gofshteyn CBD), 35356746 (autoinflammation review), 35759951 (chronic-phase anakinra/tocilizumab series). Run just fetch-reference on each and verify snippets before committing.

Primary sources cited: Hirsch 2018 consensus (Epilepsia) · Wickstrom 2022 management consensus (PMID:35951466) · Clarkson 2019 IL-1RA deficiency (PMID:30779222) · Appenzeller 2012 gene-negative (PMID:23066759) · Kenney-Jung 2016 anakinra · Nabbout 2010 ketogenic diet · Gofshteyn 2017 cannabidiol (PMID:27655472) · Chronic-phase anakinra/tocilizumab series (PMID:35759951) · "Fighting autoinflammation in FIRES" (PMID:35356746) · Fisher 2025 CSF1R (Epilepsia) · Lit review + 2 cases (PMC9756623) · Orphanet 163703 · NORD/MONDO FIRES.


That's the whole map, Harry. The one-sentence version if you're skimming: FIRES is a fever that lights a match in a brain whose anti-inflammatory fire extinguisher (IL-1RA) is functionally busted — so the innate-immune blaze and the seizures feed each other into weeks of unstoppable status epilepticus, and the survivors pay for it for life. The whole thing points at IL-1/IL-6 blockade as the rational therapy, which is exactly where the anakinra/tocilizumab evidence is pooling. Curate it as an inflammatory epileptic encephalopathy hanging off the E/I-imbalance module, not as a gene disorder — there is no gene.