Role of Encephalitis in Pathogenesis of Epilepsy

Introduction Seizures are one of the frequent sequelae of healed virus encephalitis. When focal, such seizures have been amenable to surgical therapy, and histological study of the excised areas of epileptogenic brain tissue has ordinarily shown only nonspecific gliosis and atrophy of gray and white matter, with no evidence of continuing inflammatory activity. The unsuspected finding of an apparently active encephalitic process in specimens removed from three patients with no clinical history of encephalitis has raised the question of the possible occurrence of chronic encephalitis which is subclinical except for recurring seizures. 1 Methods In order to assess the possible frequency of such a process as a cause of focal cerebral seizures, it seemed worthwhile to review a sizable segment of the series of pathological specimens removed at the Montreal Neurological Institute in the treatment of focal seizures. The microscopic material from a consecutive series of 512 surgical specimens from