Encephalitis caused by herpes simplex virus has been substantiated rarely in man. Criteria for definitive diagnosis include (1) clinical findings of acute encephalitis, (2) the presence of necrotizing brain lesions with eosinophilic intranuclear inclusions, and (3) isolation of herpes simplex virus from the brain lesions. According to Booth et al,1 there were 11 substantiated cases and 30 probable cases in children and adults reported to 1961.
In children, two patterns of herpes simplex encephalitis have occurred: (1) predominantly central nervous system lesions and (2) central nervous system lesions associated with necrotizing hepato-adrenal lesions. Skin lesions may or may not be present. Herpes simplex virus has been isolated from four cases of the first type2-5 and one case of the second type.6
Herpes simplex encephalitis may be more common than is reported, because virus isolation procedures are not commonly performed and the characteristics of the histology may not