Diagnosis and treatment of herpes simplex encephalitis.

Abstract

Herpes simplex encephalitis, HSE, remains the most common cause of sporadic fatal encephalitis in the Western World.(1–3) Since its recognition in 1941 as a cause of rapidly progressive and diffuse encephalitis in a four week old child which was fatal (4), hundreds of case reports have described various aspects of this disease in the literature. Likely, this first case report represented a child with neonatal herpes simplex virus, HSV, infection of the brain, an entity somewhat different than that which we designate as HSE of older children and adults where the infection is characterized by the focal hemorrhagic necrosis of the brain. Clinical presentation, diagnosis and outcome of patients with HSE had remained confusing until studies performed by the National Institute of Allergy and Infectious Diseases, NIAID, Collaborative Antiviral Study Group. Unequivocal diagnosis often has created both practical dilemmas (3,5,6) and intellectual controversies (7–9). The clarification of many of these issues has become possible because of a uniform diagnostic approach, namely, brain biopsy. This procedure is not routinely employed in therapeutic, natural history or diagnostic investigations performed outside the United States for the prospective evaluation of patients with focal encephalitis.