Child Neurology: Acute Necrotizing Encephalopathy of Childhood Associated With Dengue

Acute necrotizing encephalopathy of childhood (ANEC) is characterized by a rapidly progressive encephalopathy after a viral febrile illness, with multiple, symmetrical lesions in the brain including the thalami. Acute dengue fever is a known, but rare, trigger for ANEC. The clinical course of ANEC is usually fulminant and is associated with high morbidity and mortality. We describe here a prospective cohort of 5 children who presented with ANEC associated with dengue infection characterized by encephalopathy within the first week of fever, followed by a rapidly deteriorating sensorium requiring intensive care unit admission. Dengue fever was diagnosed based on a positive nonstructural protein 1 antigen test. ANEC was diagnosed based on characteristic MRI brain findings including the "trilaminar sign" in bilateral thalami combined with clinical features of severe encephalopathy, thrombocytopenia, and transaminitis. All the children required prolonged hospital stay (mean duration 30 days), with 4 of 5 children requiring mechanical ventilation (mean duration 21 days). All the children received immunomodulation with IV methylprednisolone either alone or followed by IV immunoglobulin. Although these children were bedridden at discharge (modified Rankin Scale, mRS score 4 or 5), they showed a consistent recovery in follow-up. At 6 months of follow-up, all the children were fully independent in activities of daily living (mRS scores 1-2). These cases highlight good neurologic outcomes in children with ANEC associated with dengue despite a catastrophic presentation and a protracted hospital course. The most common residual neurologic deficits noted were hand tremors and extrapyramidal dysarthria.