SURGERY FOR INTRACTABLE EPILEPSY SECONDARY TO VIRAL ENCEPHALITIS

In a series of 668 craniotomy cases for intractable epilepsy, in 11 pa tients (1.6%) the presumed aetiology was a previous episode of viral e ncephalitis, a widespread cerebral inflammation, which may therefore p roduce multifocal epilepsy. Seven patients had chronic ictal electroco rticography (ECoG). Two of these had a generalized onset, one bilatera l temporal independent onset, and four unilateral mesial temporal onse t. Three patients underwent corpus callosotomy. Eight had resections ( seven anterior temporal lobectomy (ATL), and one ATL and frontal resec tion). Pathology was hippocampal sclerosis in four, neocortical gliosi s in three and one specimen was normal. Of the resection patients, thr ee (37%) were seizure-free at a mean of 3 years postoperatively and th ree (37%) unchanged. It is concluded that where the aetiology of intra ctable epilepsy is viral encephalitis the possibility of multifocal ep ilepsy should be considered. Chronic ECoG is recommended. Nevertheless , unilateral hippocampal sclerosis can also be produced and the result s of ATL in these cases can be rewarding.