Acute necrotizing encephalopathy.

Influenza virus infection is a rare cause of neurological complications, with acute necrotizing encephalopathy (ANE) being among the deadliest. Due to the low incidence of ANE, literature about its association with influenza B infection is limited. We present the case of a 29-year-old previously healthy man with an imaging and clinical diagnosis of influenza B virus infection and sudden decline in mental status.