[Brain stem encephalitis due to herpes simplex]

Brainstem encephalitis is an unusual infection caused by a variety of agents, among them the herpes simplex (HS) virus. The difficulty of establishing a diagnosis by neurophysiological and radiological examination is greater in this type of encephalitis than in the usual form produced by HS. We describe a fatal case of brainstem encephalitis. Inflammatory and necrotic lesions in the pous and medulla confirmed the clinical diagnosis, while the etiology was determined by immuno-histo-chemical techniques and viral culture of the cerebral parenchyma. Early diagnosis of this form of encephalitis, based on new virological techniques, allows more effective antiviral treatment.