Favorable outcomes in acute necrotizing encephalopathy in a child treated with hypothermia.

Acute necrotizing encephalopathy predominately affects young children in Japan, Taiwan, and Korea. It manifests with fever, altered mental status, and seizures 2-5 days after the onset of upper respiratory infection. It is commonly associated with influenzas A, B, and H1N1. The hallmark of the encephalopathy involves multifocal, symmetric brain lesions affecting the bilateral thalami, brainstem tegmentum, cerebral periventricular white matter, cerebellum, and medulla, as visualized by computed tomography and magnetic resonance imaging. Prognoses were uniformly dismal before 1980, with high mortality rates and severe neurologic sequelae in survivors. We describe a previously healthy 4-year-old Caucasian girl who presented with fever, alterations of consciousness, and convulsions. Nasal swab revealed her to be influenza A-positive, and her magnetic resonance imaging was diagnostic of the disease. Prompt recognition of the disease and treatment with hypothermia and anti-inflammatory agents led to a favorable outcome.