Anterior opercular syndrome, caused by herpes simplex encephalitis

Bilateral frontal and parietal opercular lesions cause a syndrome characterized by paralysis of the masticatory, facial, pharyngeal, and tongue muscles (the anterior opercular syndrome). The anterior opercular syndrome can occur in patients with herpes simplex encephalitis (HSE), but in most of these patients the diagnosis of HSE was not confirmed. We describe the anterior opercular syndrome in four patients with HSE. In two of these patients, the anterior opercular syndrome dominated the clinical picture, but in the other two patients it was overshadowed by other manifestations of HSE. The diagnosis of HSE was confirmed by detection of herpes simplex virus (HSV) DNA in the CSF (two patients), culture of the HSV from a brain biopsy (one patient), and elevated HSV antibody titers in the CSF (one patient). Our patients made a partial recovery. Acute onset of weakness of masticatory, facial, pharyngeal, and glossal muscles, accompanied by fever, headache, and partial motor seizures of the face should suggest HSE.