[Influenza-Associated Encephalopathy]

Influenza-associated encephalopathy is a syndrome that chiefly manifests consciousness disturbance provoked by influenza. It is defined pathologically as acute neurological dysfunction that results from non-inflammatory brain edema. The clinical picture is so diverse that many clinical subtypes and multiple pathologies have been proposed to date. Influenza-associated encephalopathy is diagnosed and treated according to the disease guideline in Japan, which has improved the outcome of influenza-associated encephalopathy. Although influenza-associated encephalopathy had been regarded as a childhood disease in Japan, adult cases and those in the US and Europe have been reported since the 2009 pandemic. Therefore, influenza-associated encephalopathy has been spotlighted.