Diseases that mimic herpes simplex encephalitis. Diagnosis, presentation, and outcome. NIAD Collaborative Antiviral Study Group

JAMA. 1989 Jul 14;262(2):234-9.


A total of 432 patients underwent brain biopsy for presumptive herpes simplex encephalitis. Three patient groups were identified. The first group, 195 patients (45%), had herpes simplex encephalitis confirmed by the isolation of herpes simplex virus from brain tissue at biopsy (193 patients) or autopsy (2 patients). The second group, 95 patients (22%), had diseases that were identified but that were not caused by herpes simplex virus. Three subgroups were recognized: (1) 38 patients (9%) with treatable disease, (2) 40 patients (9%) with nontreatable but diagnosed viral infection, and (3) 17 patients (4%) with identified diseases neither of viral etiology nor treatable. The third group, 142 patients (33%), remained without a diagnosis. Clinical presentation of patients in the second group was similar to that of those with herpes simplex encephalitis and those without a diagnosis. Patients in the subgroup with nontreatable but diagnosed viral infections had the greatest likelihood of returning to normal.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adolescent
  • Age Factors
  • Biopsy
  • Brain / pathology
  • Consciousness
  • Diagnosis, Differential
  • Encephalitis / cerebrospinal fluid
  • Encephalitis / diagnosis*
  • Encephalitis / drug therapy
  • Encephalitis / mortality
  • Herpes Simplex / cerebrospinal fluid
  • Herpes Simplex / diagnosis*
  • Herpes Simplex / drug therapy
  • Herpes Simplex / mortality
  • Humans
  • Random Allocation
  • Simplexvirus / isolation & purification*