A 3-year-old boy diagnosed with Kawasaki disease 15 days ago is now afebrile and recovering. Repeat blood counts show a platelet count of 850000 per microlitre, rising from 320000 during the febrile phase. This finding indicates:

• A Development of macrophage activation syndrome requiring vincristine
• B Failure of IVIG therapy mandating a second dose now
• C Essential thrombocythemia needing hydroxyurea
• D Expected reactive thrombocytosis of the subacute phase, warranting continued low-dose aspirin ✓

Explanation

Thrombocytosis characteristically appears in the subacute phase of Kawasaki disease, between the second and third weeks, with counts often exceeding 800000 per microlitre. It reflects the systemic inflammatory recovery phase and is itself a supportive laboratory clue when the diagnosis was unclear earlier. Management continues with low-dose aspirin until either platelet counts normalize or echocardiographic abnormalities resolve, typically assessed at around 6 to 8 weeks.

Reference: Nelson Textbook of Pediatrics, 21st ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.