The angiographic and brain scan features of acute herpes simplex encephalitis

The angiographic findings of 11 cases of acute herpes simplex encephalitis are discussed, as are four brain scans, all of which were positive. Ten of the cases had virological proof of herpes simplex by culture or immunofluorescence studies. After five days of a pyrexial illness in which gross neurological changes develop a characteristic angiographic picture appears. This consists of a temporal lobe mass associated with changes in the capillary phase of persistent filling of some terminal arteries, local areas of hypervascularity, staining or blush, and early venous drainage, with involvement of multiple sites. Extensive or multiple areas of abnormal uptake are shown on radioisotope studies. Prior to five days from the onset of the illness, the radiological findings are not diagnostic, but all angiograms showed abnormality in at least two sites. The differential diagnosis is discussed.