Influenza A encephalopathy, cerebral vasculopathy, and posterior reversible encephalopathy syndrome: combined occurrence in a 3-year-old child.

Encephalopathy is an uncommon complication of childhood influenza infection, typically recognized during influenza epidemics. Imaging hallmarks include characteristic thalamic lesions, thalamic necrosis and hemispheric edema. We describe a child with acute influenza A associated necrotizing encephalopathy with MR angiographic evidence of significant cerebral vasculopathy and a hemispheric edema pattern consistent with PRES. This case reinforces that significant cerebral vasculopathy can accompany influenza infection and that influenza is a likely trigger for PRES.