Herpes encephalitis presenting with an opercular syndrome and epilepsia partialis continua

The opercular syndrome is a rare form of pseudobulbar palsy that is characterized by automatic-voluntary dissociative weakness of the face in addition to weak masticatory and pharyngeal muscles. It is typically seen in the setting of an acute stroke or in association with various congenital malformations of the cortex. It has also been described rarely in association with herpes encephalitis but with an abnormal cerebrospinal fluid (CSF) cell count.

We report on a 65-year-old-man with an opercular syndrome associated with epilepsia partialis continua (EPC) secondary to acute herpes simplex virus encephalitis despite an initial near normal CSF analysis.

Initial EEG was unremarkable while CSF analysis revealed changes suggestive of a traumatic tap. An opercular syndrome was diagnosed based on the classic presentation of dysarthria, facial diplegia, and hypersalivation, with corresponding MRI brain changes in the operculum. During admission, EPC developed, with continuous right facial twitching and an electroencephalographic correlate in the left centrotemporal region. The EPC initially responded to intravenous lorazepam. Phenytoin was then added for seizure prophylaxis. Herpes virus DNA was later on detected in the CSF. The patient improved with antiviral treatment except for very mild residual dysarthria.

Neurologists should be aware of the possible predilection of the herpes simplex virus for the opercular area and the need to empirically treat for herpes encephalitis even in the setting of near normal initial CSF studies in patients with a suggestive clinical presentation.