Herpes Simplex and Acute Inclusion-Body Encephalitis

Introduction During the past 5 years we have observed 6 patients with encephalitis in the wards of the Massachusetts General Hospital. Each patient presented a distinctive clinical picture with which our medical staff had not been familiar. Therefore, as might be expected, the disease occasioned considerable difficulty in diagnosis for the reason that in each instance the illness had been acute and without evident cause and had occurred at a time when there was no epidemic of encephalitis. Psychological disturbances were outstanding features during the acute phase of the illness or as major sequelae, a quality which tends to distinguish it clinically from several other types of encephalitis. In some of the patients, serologic tests were adequate to establish the presence of an infection caused by herpes simplex virus; in others, the existence of an "inclusion-body" encephalitis was demonstrated pathologically. Our data provide no clue as to the manner in