Postinfectious Autoimmune Encephalitis Can Be a Sequela of Herpes Simplex Encephalitis

Herpes simplex encephalitis is a severe infection with high morbidity and mortality. The disease is typically monophasic, but a minority of patients relapse in the subsequent months. Some patients relapse because of persistent herpes virus; others relapse with no evidence of a virus and are refractory to additional acyclovir treatment. Some of the latter “relapsing” patients have improved after steroids, and antineuronal antibodies have been reported.

This prospective, multicenter cohort included 51 eligible patients with herpes simplex virus (HSV) encephalitis, none of whom had detectable antineuronal antibodies at first presentation. Probable autoimmune encephalitis was defined as new or worsening central nervous system symptoms for at lea…