Kawasaki Disease
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Direct answer
Kawasaki disease is an acute, self-limited systemic vasculitis of medium-sized arteries, chiefly of children under five years, whose importance is coronary artery aneurysm — the leading acquired heart disease of children. Diagnosis requires fever of five days or more with at least four of five features: bilateral non-exudative conjunctival injection, oral mucosal changes, peripheral extremity changes, polymorphous rash and cervical lymphadenopathy. Treatment is a single 2 g/kg intravenous immunoglobulin infusion with aspirin, ideally within the first ten days, which sharply reduces coronary complications.
What you must remember
- Criteria: fever of five days or more plus at least four of five — bilateral bulbar conjunctival injection without exudate, lip and mouth changes (strawberry tongue, cracked red lips), extremity changes (indurative oedema acutely, periungual desquamation later), polymorphous non-vesicular rash, and cervical nodes of at least 1.5 centimetres.
- Supportive clues: irritability, redness of a BCG scar, sterile pyuria, deranged liver enzymes and arthritis; thrombocytosis rises in the second week.
- Incomplete disease: fewer criteria with compatible laboratory changes and echocardiographic findings still warrants treatment, especially in young infants with persistent fever.
- Coronary risk: aneurysms complicate a meaningful proportion of untreated children; echocardiography is done at diagnosis and follow-up, with giant aneurysms (beyond about 8 millimetres) carrying thrombosis risk.
- Treatment: intravenous immunoglobulin 2 g/kg as a single infusion, ideally days five to seven; fever persisting 36 hours later defines resistance, treated with repeat infusion or infliximab.
- Aspirin: current international guidance prefers moderate anti-inflammatory doses (30-50 mg/kg/day) acutely — older textbooks list 80-100 mg/kg/day — stepping down to 3-5 mg/kg/day once afebrile, continued about six to eight weeks if coronary arteries are normal.
- Live vaccines: measles and varicella vaccination is deferred for about 11 months after immunoglobulin.
Common confusion
Kawasaki disease is most often confused with measles and scarlet fever. Measles has exudative conjunctivitis, Koplik spots, cough and coryza; scarlet fever has exudative pharyngitis, Pastia's lines, a sandpaper rash and responds promptly to antibiotics — while Kawasaki fever smoulders unresponsive to both. Desquamation timing also confuses: peeling of fingers and toes belongs to the subacute phase, often absent in week one, so a child can fulfil criteria without it. And do not wait for a full house of criteria: young infants present incompletely yet carry the highest aneurysm risk.
Exam-focused takeaway
NEET-PG builds Kawasaki questions around the criteria count, the two drugs and the timing rule — IVIG 2 g/kg plus aspirin within ten days. Vignettes describe an irritable toddler with five days of fever, red eyes without pus, cracked lips and a flared BCG scar; the next-best-step answer is echocardiography and IVIG, not antibiotics. Learn the discriminators against measles and scarlet fever, the aspirin dose shift in recent guidance, and the live-vaccine deferral. "Leading acquired heart disease in children" is the recurring one-liner.
Frequently asked questions
What are the diagnostic criteria?
Fever of five days or more plus at least four of five: non-exudative conjunctivitis, oral changes, extremity changes, polymorphous rash and cervical lymphadenopathy.
Why treat within ten days?
Immunoglobulin given in the first ten days — ideally around days five to seven — markedly reduces coronary artery aneurysms; later treatment protects far less.
What is the standard treatment?
A single infusion of intravenous immunoglobulin 2 g/kg with aspirin; fever persisting 36 hours afterwards defines resistance, treated with repeat infusion or infliximab.
What dose of aspirin is used?
Current international guidance prefers moderate-dose aspirin (30-50 mg/kg/day) acutely, shifting to a low antiplatelet dose (3-5 mg/kg/day) once afebrile; older texts list higher doses.
Can it be diagnosed with fewer criteria?
Yes — incomplete Kawasaki disease: fewer features with supportive laboratory markers and echocardiography, particularly in young infants, still warrants treatment.