A 4-month-old boy has had fever for 9 days. He is irritable with minimal physical findings apart from a faint truncal rash. CRP is 90 mg/L and ESR is 70 mm/hr. CSF shows pleocytosis, urine culture is sterile, and echocardiography shows a right coronary artery Z-score of 3.2. What is the next step?
- A Treat as incomplete Kawasaki disease with IVIG and aspirin ✓
- B Continue antibiotics pending repeat cultures
- C Reassure and review in 2 weeks since criteria are unmet
- D Start intravenous methylprednisolone as first-line therapy
Correct answer: A. Treat as incomplete Kawasaki disease with IVIG and aspirin
Explanation
Infants under 6 months are the classic group for incomplete Kawasaki disease, and any infant with fever exceeding 7 days without another explanation warrants evaluation. Elevated ESR and CRP plus a coronary Z-score above 2.5 meets AHA criteria for treating incomplete disease. Steroids are reserved for refractory cases, not first line. Continuing antibiotics risks missing the window for IVIG, which must be given within 10 days of onset to best prevent coronary aneurysms.
Reference: Nelson Textbook of Pediatrics, 21st ed.
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Written and medically reviewed by the StethoPrep medical team.