Editor,—Heat stroke is a potentially fatal disorder but often difficult to diagnose in children. Peripheral neutrophils with radially hypersegmented nuclei—“botryoid” neutrophils—are known to be characteristic of heat stroke in adults.1 We describe three children exhibiting botryoid neutrophils who presented with acute encephalopathy.

Patient 1 was a 7 month old girl with severe cerebral palsy who became unresponsive after being kept warm with a hot pack in winter. She was febrile (⩾ 42°C) and hypotensive, and she had several seizures and bloody stools. After supportive treatment including cooling procedures, she returned completely to her pre-illness state 14 days later.

Patient 2, a previously …