Adult-onset acute necrotizing encephalopathy following febrile diarrheal illness

Acute necrotizing encephalopathy (ANE) is a rare, rapidly progressive encephalopathy most commonly described in pediatric populations, with adult-onset cases being exceedingly rare. We report a case of a 24-year-old previously healthy male who developed ANE following a prodromal febrile diarrheal illness. The patient initially presented with generalized seizures and altered mental status, progressing rapidly to coma and requiring mechanical ventilation. Brain magnetic resonance imaging (MRI) demonstrated characteristic bilateral symmetrical T2 hyperintensities in the thalami, basal ganglia, brainstem, and cerebellum—findings strongly indicative of ANE. Despite early and aggressive treatment with high-dose corticosteroids, plasmapheresis, and intravenous immunoglobulins, the patient’s clinical course was complicated by refractory seizures and the onset of multidrug-resistant ventilator-associated pneumonia. Prolonged sedation, tracheostomy, and broad-spectrum antimicrobial therapy were necessary for ongoing management. Ultimately, the patient suffered persistent neurological deficits. This case underscores the diagnostic challenges of ANE in adults. It highlights the need for early recognition, multidisciplinary intervention, and vigilance for secondary complications to improve outcomes in this rare but severe encephalopathy.