Fatal Influenza A(H1N1)pdm09 Encephalopathy in Immunocompetent Man

We report an immunocompetent patient who had fatal encephalopathy after mild influenza.He rapidly died after unusual symptoms related to intracerebral thrombosis and hemorrhage.A brain biopsy specimen was positive for influenza A(H1N1)pdm09 virus RNA, but a lung biopsy specimen and cerebrospinal spinal fluid samples were negative.I nfluenza-related neurologic complications are rare, es- pecially in immunocompetent adults.The clinical signs and severity of this pathology are variable.We report a lifethreatening specific complication of influenza A(H1N1) pdm09 infection that was responsible for lethal central venous thrombosis. The StudyA previously healthy 26-year-old man from northern Africa was admitted to our emergency department in Lyon, France, in November 2009, during the peak of influenza A(H1N1)pdm09 infection in France (1), because of cephalalgia, confusion, and lethargy.A Glasgow Coma Score was 12.He had no history of influenza vaccination.Initial symptoms (fever, cough, and myalgia) began a week before admission.Several members of his family had similar symptoms.There were no risk factors indicative of a complicated disease.Body temperature at admission was 36.8°C, and he had no respiratory distress or signs of shock.Results of a chest radiograph were normal.During the first hours after admission, the patient lost consciousness (Glasgow coma score 3), which was associated with a seizure.His pupils were anisocoric and