Kawasaki Disease

Kawasaki Disease - Fiery Vessel Fever

• Definition: Acute febrile mucocutaneous lymph node syndrome, a systemic illness.
• Nature: Primarily a medium-vessel vasculitis.
• Age: Typically affects children <5 years; peak incidence 6 months to 2 years.
• Epidemiology: Higher incidence in Asian populations, especially Japanese.

⭐ Untreated, up to 25% of children may develop coronary artery aneurysms.

Kawasaki Disease - CRASH & Burn Alert

📌 CRASH & Burn: Fever (≥5 days) is the "Burn" - persistent and often high-grade.

• Diagnostic Criteria (Typical KD): Fever ≥5 days PLUS ≥4 of the following:

  • Conjunctivitis: Bilateral, non-exudative, limbic-sparing.
  • Rash: Polymorphous (maculopapular, morbilliform, or targetoid), often truncal, can involve perineum.
  • Adenopathy: Cervical, usually unilateral, firm, non-suppurative, node ≥1.5cm.
  • Strawberry tongue/Lip changes: Diffuse oropharyngeal erythema, dry, red, cracked lips.
  • Hand/foot changes: Acute erythema/edema of palms/soles; convalescent periungual desquamation (2-3 weeks).

• Incomplete KD: Suspect with unexplained fever ≥5 days AND <4 CRASH criteria. Requires supportive lab findings (e.g., ↑CRP ≥3mg/dL, ↑ESR ≥40mm/hr) OR positive echocardiogram. Always refer to AHA guidelines for full criteria.

⭐ Coronary artery aneurysms are the most serious complication, mandating echocardiography for all suspected cases to assess for cardiac involvement and guide treatment duration with IVIG and aspirin.

Kawasaki Disease - Lab Sleuth & Mimics

• Labs:
  • ↑ESR, ↑CRP (acute phase reactants)
  • Leukocytosis (neutrophilia)
  • Thrombocytosis (late, characteristic; peaks 2-4 wks)
  • Sterile pyuria
  • Mild ↑transaminases
• Echo: CRUCIAL (baseline & follow-up) for coronary artery aneurysm (CAA) detection.

  ⭐ Thrombocytosis is a late but highly characteristic finding in Kawasaki Disease.

• DDx:
  • Viral exanthems (Measles, Adenovirus)
  • Scarlet fever
  • Stevens-Johnson Syndrome (SJS)
  • Staphylococcal Scalded Skin Syndrome (SSSS)
  • Juvenile Idiopathic Arthritis (JIA)

Kawasaki Disease - Heart Shield Protocol

• Primary Goal: Prevent Coronary Artery Aneurysms (CAA). Treat ideally within 10 days of fever onset.
• Standard Therapy:
  • IVIG: 2g/kg (single infusion, 10-12h).
  • Aspirin:
    • Initial High-Dose: 80-100mg/kg/day (q6h).
    • Maintenance Low-Dose: 3-5mg/kg/day (once afebrile for 48-72h; continue 6-8 wks if no CAA, longer if CAA).
• Refractory KD (Fever ≥36h post-IVIG):
  • 2nd IVIG dose (2g/kg).
  • Corticosteroids.
  • Infliximab.
• Key Complications:
  • Coronary Artery Aneurysms (CAA) - monitor with Echo.
  • Myocarditis, pericarditis, valvular issues.
  • CAA Management: Long-term low-dose Aspirin; anticoagulation for giant aneurysms.

⭐ Giant aneurysms (diameter >8mm or Z-score ≥10) carry the highest risk of thrombosis and require anticoagulation in addition to aspirin.

High‑Yield Points - ⚡ Biggest Takeaways

• Kawasaki Disease (KD): acute febrile vasculitis in children < 5 years.
• Diagnosis relies on CRASH & Burn criteria: Conjunctivitis, Rash, Adenopathy, Strawberry tongue, Hands/feet changes, plus Fever >5 days.
• Most critical complication: Coronary artery aneurysms; monitor with echocardiogram.
• Standard treatment: Intravenous Immunoglobulin (IVIG) and high-dose Aspirin in acute phase.
• Aspirin is later reduced to low-dose for antiplatelet effect.
• Untreated KD can lead to significant cardiac morbidity.