Fever, Fits, and Coma — The Unexpected Diagnosis: A Case of Acute Disseminated Encephalomyelitis (ADEM)

Acute Disseminated Encephalomyelitis (ADEM) is a rare, immune-mediated demyelinating disorder of the central nervous system, usually following infection or vaccination. We report a 13-year-old boy presenting with fever, seizures, and coma, initially diagnosed as viral meningoencephalitis. Despite empirical antimicrobials, his condition worsened and required mechanical ventilation. Brain MRI revealed multiple bilateral T2/FLAIR hyperintense lesions involving deep and subcortical white matter, consistent with ADEM. High-dose intravenous methylprednisolone followed by intravenous immunoglobulin (IVIG) led to full neurological recovery within six days. This case highlights the diagnostic challenge of differentiating ADEM from infectious encephalitis in resource-limited ICUs, and the importance of early immunotherapy once infection is excluded. Awareness of this reversible condition can prevent prolonged illness and unnecessary antibiotic exposure, improving outcomes in critically ill pediatric patients.

Keywords: Acute disseminated encephalomyelitis, pediatric encephalopathy, intensive care, demyelinating disease, immunotherapy, post-infectious encephalitis