Kawasaki Disease

Definition | Aetiology | Pathophysiology | Risk Factors | Signs and Symptoms | Investigations | Management

Definition

Kawasaki disease is an acute systemic vasculitis of unknown aetiology, primarily affecting children under 5 years old, and is the leading cause of acquired heart disease in this age group.

Aetiology

  • Idiopathic: exact cause unknown but thought to be immune-mediated.
  • Infectious triggers: possible viral or bacterial associations.
  • Genetic predisposition: increased risk in East Asian populations and familial clustering.

Pathophysiology

  • Widespread inflammation of medium sized arteries, particularly the coronary arteries.
  • Endothelial dysfunction leads to aneurysm formation and risk of thrombosis.
  • Systemic inflammation affects mucous membranes, skin, and lymph nodes.

Risk Factors

  • Age: most common in children under 5 years old.
  • Ethnicity: higher prevalence in East Asian populations.
  • Male sex.
  • Genetic predisposition.

Signs and Symptoms

Kawasaki disease is diagnosed clinically and is characterised by fever lasting ≥5 days plus at least four of the following features:

  • Conjunctivitis: bilateral, non-purulent.
  • Rash: polymorphous, non-vesicular.
  • Oral mucosal changes: red lips, strawberry tongue, erythema of the oropharynx.
  • Extremity changes: erythema and oedema of hands/feet, followed by desquamation.
  • Cervical lymphadenopathy: usually unilateral and >1.5 cm.

Investigations

  • Inflammatory markers: raised CRP and ESR.
  • Full blood count: leukocytosis, thrombocytosis (late stage), normocytic anaemia.
  • Liver function tests: transaminitis and hypoalbuminaemia may be present.
  • Urinalysis: sterile pyuria.
  • Echocardiography: essential to assess coronary artery involvement.

Management

1. Acute Phase:

  • IV immunoglobulin (IVIG): first line treatment to reduce coronary artery complications.
  • Aspirin: high dose during the acute phase, followed by low-dose for thromboprophylaxis.

2. Monitoring and Long Term Care:

  • Regular echocardiography for coronary artery aneurysm surveillance.
  • Cardiology follow up for patients with persistent coronary abnormalities.

3. Referral:

  • Paediatrics: urgent referral for suspected cases.
  • Cardiology: if coronary artery involvement is present.
PaediatricsmypanotesKawasaki Disease