herpes simplex encephalitis, a necrotizing inflammation of the brain that follows an infection with herpes simplex virus. It is a common acute form of encephalitis and is similar to other viral encephalitis infections. Repeated seizures occur early in the course, and there is severe hemorrhagic necrosis. Affected areas of the brain are usually the orbital portions of the frontal lobes and the inferomedial portions of the temporal lobe. Persons of any age may be infected, but cerebral sequelae (caused by HSV2) are more likely to occur in infants. The mortality rate varies, but even desperately ill patients may recover completely.
