Acute necrotizing encephalopathy in a child with H1N1 influenza infection.

Since the World Health Organization declared a global pandemic of novel influenza A H1N1 in June 2009, there has been a sustained rise in the number of cases of this strain of influenza. Although most cases are mild with complete and uneventful recovery, multiple cases of severe infection with complications including death have been reported. To the best of our knowledge, the majority of fatal outcomes in the United States have been related to pulmonary complications. We report a 12-year-old girl infected with influenza A H1N1 whose clinical course was complicated by rapid progressive neurologic deterioration and striking CT and MRI findings consistent with acute necrotizing encephalopathy (ANE). To our knowledge this has not been reported in the pediatric radiology literature. We hope this case will alert radiologists to this complication and familiarize radiologists with imaging findings that herald ANE.