Acute hemorrhagic leukoencephalitis and hypoxic brain injury associated with H1N1 influenza.

OBJECTIVE: To describe the first adult with neurologic complications associated with H1N1 influenza virus infection. DESIGN: Case report. Patient A 40-year-old man with severe H1N1 influenza infection with prolonged hypoxia and critical illness who remained comatose after withdrawal of sedatives and paralytics. INTERVENTIONS: Clinical examination and magnetic resonance imaging. RESULTS: Brain imaging revealed multifocal T2 hyperintense lesions, edema, and hemorrhages consistent with acute hemorrhagic leukoencephalitis (AHL) and restricted diffusion in the basal ganglia consistent with hypoxic brain injury. The patient remained in a severely disabled state following treatment with plasma exchange and high-dose corticosteroids. CONCLUSIONS: This is the first study of neurologic complications associated with H1N1 influenza infection in adults. Severe brain injury can occur by 2 distinct mechanisms: a fulminant autoimmune demyelinating insult (AHL) and hypoxic brain injury. Clinicians should be aware of these potential complications so that appropriate imaging and treatment can be considered.