A boy with fever, shock and coma

A 12-year-old boy with fever, headache, shock, and coma presents a diagnostic challenge

A previously well 12-year-old boy presented with a one-day history of vomiting, fever, and headache.

On examination, he was tachycardic and poorly perfused. He had left-sided ptosis and a dilated non-reactive left pupil, and his Glasgow coma score was 8. He had hyponatraemia (Na 129mmol/L; normal 135-145mmol/L), normal potassium, normal glucose, leucocytosis, neutrophilia, and raised CRP (305mg/L; normal <5mg/L).

Initial management
Our working diagnosis was infective meningo-encephalitis with cerebral oedema, so he was intubated and given intravenous 3%