Computed tomography in herpes simplex encephalitis.

Nine patients with herpes simplex encephalitis examined by CT scan were reviewed. A total of 15 satisfactory scans was analyzed. The majority of our cases had CT scan abnormalities: lucency 63% (5 of 8, one case with suboptimal scan), mass effect 50% (4 of 8), abnormal contrast enhancement 57% (4 of 7). The earliest CT scan finding was lucency, presented in two out of three cases studied within 48 hours following onset of symptoms. The primary role of CT scan is to support the suspected diagnosis of herpes simplex encephalitis as well as to indicate the best site for brain biopsy and to permit early effective treatment with adenine arabinoside.