Computed tomography of herpes simplex encephalitis

CT findings were studied in 8 survival cases of herpes simplex encephalitis (HSE) which had been diagnosed with a serial antibody titer against HSV in serum and CSF. CT scans obtained from 3 days to 2 weeks after the onset were analyzed for pictures of the acute stage in 4 cases of HSE. CT scans of the 8 cases after 1 month to 3 years had passed were examined for the follow-up study. 1) CT findings at the acute stage: A low density in the unilateral temporal lobe was observed in 3 of 4 cases, which appeared from 5 days to 13 days (av. 8 days) after the onset. In the other case, a low-density area occurred in the right hemisphere. A mass effect, such as a midline shift and the compression of the anterior horm, was found in most cases. Postocontrast CT scans showed a streak linear or gyral enhancement. 2) Follow-up CT after the acute stage: In the 2 infantile cases, a large low density was observed in the bilateral temporal, parietal lobes. On the other hand, in 4 of the 6 adult cases, the low density was localized in the temporal lobe with brain atrophy. CT scans in the other 2 cases, however, showed a distribution similar to that of the infantile cases. CT findings at the acute stage in HSE were discussed in comparison with other diagnostic methods. Furthermore, the delayed changes in CT as determined by the follow-up study were also mentioned. (author)