Neonatal herpes simplex encephalitis: correlation of clinical and CT findings.

Review of 31 computed tomographic (CT) scans in 15 neonates with herpes simplex encephalitis (HSE) type 2 revealed the most characteristic early findings to be patchy and widespread areas of low attenuation, primarily in white matter, with minimal contrast material enhancement in a meningeal pattern. The low-attenuation lesions increased rapidly in size and prominence during the course of the disease. This was usually accompanied by increased attenuation of cortical gray matter that persisted for weeks to months. Atrophic changes appeared rapidly, being evident in the 3d week. Late findings consisted of very extensive, diffuse, low attenuation of white matter with cortical atrophy. Calcification assumed a variety of distributions, from punctate to an extensive gyral pattern. The cerebellum was involved in nine patients. Early CT findings were not good predictors of outcome, but later serial CT scans showing progression or stability of findings were more accurate in prognosis. CT serves primarily to confirm the diagnosis of neonatal HSE.