Capillary leak syndrome is a rare vascular permeability disorder in which episodic endothelial barrier failure causes rapid movement of plasma and proteins from the intravascular space into the interstitium. The clinical syndrome is characterized by hypotension, edema, hemoconcentration, and hypoalbuminemia; idiopathic recurrent disease is often referred to as systemic capillary leak syndrome or Clarkson disease.
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name: capillary leak syndrome
creation_date: '2026-04-14T12:00:00Z'
updated_date: '2026-04-15T01:00:00Z'
category: Complex
synonyms:
- systemic capillary leak syndrome
- Clarkson disease
description: >-
Capillary leak syndrome is a rare vascular permeability disorder in which
episodic endothelial barrier failure causes rapid movement of plasma and
proteins from the intravascular space into the interstitium. The clinical
syndrome is characterized by hypotension, edema, hemoconcentration, and
hypoalbuminemia; idiopathic recurrent disease is often referred to as
systemic capillary leak syndrome or Clarkson disease.
disease_term:
preferred_term: capillary leak syndrome
term:
id: MONDO:0001956
label: capillary leak syndrome
parents:
- vascular disorder
- immune-mediated disease
pathophysiology:
- name: Endothelial barrier dysfunction
description: >-
The central pathogenic event is abrupt failure of the endothelial barrier,
allowing proteins and plasma water to escape from the vascular lumen.
cell_types:
- preferred_term: endothelial cell
term:
id: CL:0000115
label: endothelial cell
biological_processes:
- preferred_term: regulation of vascular permeability
term:
id: GO:0043114
label: regulation of vascular permeability
modifier: ABNORMAL
evidence:
- reference: PMID:29732372
reference_title: The Role of Failing Autonomic Nervous System on Life-Threatening Idiopathic Systemic Capillary Leak Syndrome.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
In acute phases, endothelial cells sieving properties are almost
completely disrupted resulting in massive fluid and protein loss.
explanation: >-
This directly supports abrupt endothelial barrier dysfunction as the
initiating pathogenic event in idiopathic systemic capillary leak
syndrome.
downstream:
- target: Plasma extravasation
description: Barrier failure permits rapid capillary leakage.
- name: Plasma extravasation
description: >-
Intravascular proteins and fluid shift into the interstitial compartment,
contracting effective circulating volume.
biological_processes:
- preferred_term: regulation of vascular permeability
term:
id: GO:0043114
label: regulation of vascular permeability
modifier: INCREASED
evidence:
- reference: PMID:29732372
reference_title: The Role of Failing Autonomic Nervous System on Life-Threatening Idiopathic Systemic Capillary Leak Syndrome.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
The resulting shift of fluids and proteins from the intravascular to the
interstitial compartment causes the hypovolemic shock that characterizes
disease recurrences.
explanation: >-
This directly supports plasma and protein extravasation into the
interstitium as the core downstream consequence of barrier failure.
downstream:
- target: Intravascular volume depletion
description: Fluid loss from the vascular space lowers effective preload and perfusion.
- target: Generalized edema
description: Extravasated fluid accumulates in tissues during the leak phase.
- target: Hemoconcentration
description: Plasma-volume loss concentrates circulating blood elements.
causal_link_type: DIRECT
- target: Hypoalbuminemia
description: Protein-rich plasma leakage lowers circulating serum albumin.
causal_link_type: DIRECT
- name: Intravascular volume depletion
description: >-
Severe plasma loss produces hypotension and shock physiology during acute
attacks.
notes: >-
This is a systemic hemodynamic consequence of capillary leak, and a more
specific cell-level GO process was not added in this curation pass.
evidence:
- reference: PMID:29732372
reference_title: The Role of Failing Autonomic Nervous System on Life-Threatening Idiopathic Systemic Capillary Leak Syndrome.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
The resulting shift of fluids and proteins from the intravascular to the
interstitial compartment causes the hypovolemic shock that characterizes
disease recurrences.
explanation: >-
This directly supports intravascular volume depletion and hypovolemic
shock as immediate consequences of plasma leakage.
downstream:
- target: Hypotension
description: Effective circulating-volume loss produces hypotension during acute attacks.
causal_link_type: DIRECT
- name: Generalized edema
description: >-
Interstitial fluid accumulation follows the capillary leak and contributes
to the characteristic edematous phase of the disorder.
biological_processes:
- preferred_term: regulation of vascular permeability
term:
id: GO:0043114
label: regulation of vascular permeability
modifier: INCREASED
evidence:
- reference: PMID:29732372
reference_title: The Role of Failing Autonomic Nervous System on Life-Threatening Idiopathic Systemic Capillary Leak Syndrome.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Capillary leakage leads to hemoconcentration, hypoalbuminemia,
generalized edema, and refractory hypovolemic shock with subsequent
complications (8).
explanation: >-
This directly supports generalized edema as a defining consequence of the
leak phase.
downstream:
- target: Edema
description: Interstitial fluid accumulation is expressed clinically as generalized edema.
causal_link_type: DIRECT
phenotypes:
- name: Hypotension
category: Cardiovascular
description: >-
Acute attacks commonly present with marked hypotension from abrupt
intravascular volume depletion.
phenotype_term:
preferred_term: Hypotension
term:
id: HP:0002615
label: Hypotension
evidence:
- reference: PMID:29732372
reference_title: The Role of Failing Autonomic Nervous System on Life-Threatening Idiopathic Systemic Capillary Leak Syndrome.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Capillary leakage leads to hemoconcentration, hypoalbuminemia,
generalized edema, and refractory hypovolemic shock with subsequent
complications (8).
explanation: >-
This directly supports hypotensive shock physiology during acute attacks.
- name: Hemoconcentration
category: Laboratory
description: >-
Acute leak episodes characteristically produce hemoconcentration from rapid
plasma-volume loss.
notes: No exact HPO term for hemoconcentration was identified in this curation pass.
evidence:
- reference: PMID:29732372
reference_title: The Role of Failing Autonomic Nervous System on Life-Threatening Idiopathic Systemic Capillary Leak Syndrome.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Capillary leakage leads to hemoconcentration, hypoalbuminemia,
generalized edema, and refractory hypovolemic shock with subsequent
complications (8).
explanation: >-
This directly supports hemoconcentration as part of the classic
capillary leak syndrome triad.
- name: Edema
category: General
description: >-
Generalized edema develops as plasma leaks into the interstitial
compartment.
phenotype_term:
preferred_term: Edema
term:
id: HP:0000969
label: Edema
evidence:
- reference: PMID:29732372
reference_title: The Role of Failing Autonomic Nervous System on Life-Threatening Idiopathic Systemic Capillary Leak Syndrome.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Capillary leakage leads to hemoconcentration, hypoalbuminemia,
generalized edema, and refractory hypovolemic shock with subsequent
complications (8).
explanation: >-
This directly supports generalized edema as a major clinical
manifestation.
- name: Hypoalbuminemia
category: Laboratory
description: >-
Serum albumin falls during episodes because protein-rich plasma escapes the
vascular compartment.
phenotype_term:
preferred_term: Hypoalbuminemia
term:
id: HP:0003073
label: Hypoalbuminemia
evidence:
- reference: PMID:29732372
reference_title: The Role of Failing Autonomic Nervous System on Life-Threatening Idiopathic Systemic Capillary Leak Syndrome.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
Capillary leakage leads to hemoconcentration, hypoalbuminemia,
generalized edema, and refractory hypovolemic shock with subsequent
complications (8).
explanation: >-
This directly supports hypoalbuminemia as part of the defining
laboratory triad.
biochemical:
- name: Monoclonal IgG paraprotein
presence: ABNORMAL
notes: >-
Idiopathic systemic capillary leak syndrome can be associated with a
monoclonal gammopathy.
evidence:
- reference: PMID:29732372
reference_title: The Role of Failing Autonomic Nervous System on Life-Threatening Idiopathic Systemic Capillary Leak Syndrome.
supports: PARTIAL
evidence_source: HUMAN_CLINICAL
snippet: >-
Serum proteins electrophoresis revealed a monoclonal IgG k component.
explanation: >-
This single-patient report supports monoclonal gammopathy as a clinically
relevant association in idiopathic systemic capillary leak syndrome.
genetic: []
environmental: []
treatments:
- name: Acute hemodynamic support
treatment_term:
preferred_term: Pharmacotherapy
term:
id: NCIT:C15986
label: Pharmacotherapy
therapeutic_agent:
- preferred_term: norepinephrine
term:
id: CHEBI:33569
label: noradrenaline
description: >-
Acute attacks are managed with cautious intravenous fluid resuscitation and
hemodynamic support.
evidence:
- reference: PMID:29732372
reference_title: The Role of Failing Autonomic Nervous System on Life-Threatening Idiopathic Systemic Capillary Leak Syndrome.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
He was given supportive treatment with careful 200 ml boluses of 6%
hydroxyethyl starch (HES) 130/0.4 and norepinephrine infusion at
0.1 mcg/kg/min.
explanation: >-
This directly supports cautious fluid resuscitation and vasopressor
support during severe acute attacks.
- name: Theophylline prophylaxis
treatment_term:
preferred_term: Pharmacotherapy
term:
id: NCIT:C15986
label: Pharmacotherapy
therapeutic_agent:
- preferred_term: theophylline
term:
id: CHEBI:28177
label: theophylline
description: >-
Oral theophylline has been used as prophylaxis against recurrent idiopathic
systemic capillary leak attacks.
evidence:
- reference: PMID:29732372
reference_title: The Role of Failing Autonomic Nervous System on Life-Threatening Idiopathic Systemic Capillary Leak Syndrome.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
After 1 week, he was discharged home on oral theophylline as prophylaxis
of recurrences (9).
explanation: >-
This directly supports theophylline as a documented prophylactic therapy
in idiopathic systemic capillary leak syndrome.
diagnosis:
- name: Clinical assessment
diagnosis_term:
preferred_term: clinical assessment
term:
id: MAXO:0000487
label: clinical assessment
description: >-
Diagnosis relies on recognizing recurrent episodes of hypotension and edema
with compatible laboratory findings.
results: The triad of hypotension, hemoconcentration, and hypoalbuminemia supports capillary leak syndrome.
evidence:
- reference: PMID:29732372
reference_title: The Role of Failing Autonomic Nervous System on Life-Threatening Idiopathic Systemic Capillary Leak Syndrome.
supports: SUPPORT
evidence_source: HUMAN_CLINICAL
snippet: >-
The diagnosis of SCLS was made at that time according to the triad of
sudden circulatory collapse, hemoconcentration, and hypoalbuminemia, and
then he was transferred to our ICU.
explanation: >-
This directly supports the diagnostic triad used in clinical assessment
of systemic capillary leak syndrome.
differential_diagnoses: []
clinical_trials: []
datasets: []
This report is retrieval-only and is generated directly from Asta results.
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