What are the symptoms and treatment of Kawasaki syndrome?

Symptoms and Treatment of Kawasaki Disease

Kawasaki disease is an acute, self-limited vasculitis of childhood characterized by fever lasting at least 5 days, plus four of five principal clinical features: bilateral non-exudative conjunctivitis, oral mucosal changes, polymorphous rash, extremity changes, and cervical lymphadenopathy, with treatment consisting of intravenous immunoglobulin (IVIG) and aspirin to prevent coronary artery complications. 1, 2

Principal Diagnostic Criteria

• Fever: Typically high-spiking (>39°C to 40°C), persisting for at least 5 days if untreated 3
• Bilateral bulbar conjunctival injection: Non-exudative, without exudate, often sparing the limbus 3
• Changes in lips and oral cavity: Erythema and cracking of lips, strawberry tongue, diffuse injection of oral and pharyngeal mucosae 3
• Polymorphous exanthema/rash: Most commonly diffuse maculopapular eruption, but can also be scarlatiniform, erythema multiforme-like, or urticarial 3, 1
• Changes in extremities: Acute phase - erythema and edema of hands and feet; subacute phase - periungual desquamation (peeling) beginning 2-3 weeks after fever onset 3, 1
• Cervical lymphadenopathy: Usually unilateral, ≥1.5 cm in diameter, least common of the principal features 3

Other Clinical and Laboratory Findings

• Cardiovascular: Gallop rhythm, distant heart sounds, ECG changes, cardiomegaly, pericardial effusion, coronary aneurysms 3
• Gastrointestinal: Diarrhea, vomiting, abdominal pain, hydrops of gallbladder, mild jaundice 3, 1
• Blood: Elevated ESR, leukocytosis with left shift, positive CRP, hypoalbuminemia, mild anemia 3, 1
• Urinary: Sterile pyuria 1, 4

Diagnosis of Incomplete Kawasaki Disease

• Consider incomplete Kawasaki disease in children with fever ≥5 days and only 2-3 principal clinical features 1, 4
• Infants <6 months with fever ≥7 days without other explanation should be evaluated for incomplete Kawasaki disease 1, 4
• Echocardiography is crucial for evaluation of suspected incomplete Kawasaki disease 1, 4

Treatment Protocol

Initial Treatment

• IVIG: Administer 2 g/kg as a single infusion as early as possible within the first 10 days of fever onset 2, 5
• Aspirin: High-dose (80-100 mg/kg/day divided into four doses) until the patient is afebrile for 48-72 hours 2, 5
• After fever resolution, reduce to low-dose aspirin (3-5 mg/kg/day) and continue for 6-8 weeks if no coronary abnormalities are present 2, 6
• For children who develop coronary abnormalities, aspirin may be continued indefinitely 2

Management of IVIG-Resistant Disease (10-20% of patients)

• Second dose of IVIG (2 g/kg) for persistent or recrudescent fever 36 hours after initial IVIG infusion 2
• Consider corticosteroids for patients who remain febrile after two doses of IVIG 2
• Infliximab (TNF-α inhibitor) is effective in treating IVIG-resistant cases 2

Long-term Management Based on Coronary Involvement

• No coronary abnormalities: Low-dose aspirin for 6-8 weeks 2
• Small coronary aneurysms: Long-term low-dose aspirin indefinitely 2
• Moderate-sized aneurysms (4-6 mm): Aspirin plus a second antiplatelet agent 2
• Giant aneurysms (≥8 mm): Low-dose aspirin plus warfarin (target INR 2.0-3.0) or aspirin plus therapeutic doses of low-molecular-weight heparin for infants 2

Important Clinical Pearls and Pitfalls

• Clinical features may not all be present simultaneously; careful history-taking is essential 1
• The diagnosis can be made with fewer than 5 days of fever if typical clinical findings are present 1
• Highest risk for coronary artery thrombosis occurs within the first 3 months, with peak incidence in the first 15-45 days 2
• Delaying treatment beyond 10 days increases the risk of coronary artery abnormalities 2
• Incomplete Kawasaki disease is more common in children under 1 year, who paradoxically have higher rates of coronary aneurysms if not treated 2
• Annual influenza vaccination is recommended for children on long-term aspirin therapy 2
• Measles and varicella immunizations should be deferred for 11 months after high-dose IVIG administration 2
• Ibuprofen should be avoided in children taking aspirin for its antiplatelet effects 2