Imaging studies in neonatal herpes simplex encephalitis.

Herpes simplex encephalitis (HSE) is the most common form of sporadic encephalitis in man and usually results in death or permanent neurologic deficit. Neonatal HSE does not show the characteristic anatomic localization in the temporal lobe observed in adults and in older children which suggests that the disease process is different in this age group. The abnormalities observed with radionuclide brain imaging and computed tomography (CT) are more diffuse and bilateral. The clinical outcome of the disease is highly dependent on early institution of therapy. Therefore, early diagnosis is critical. Knowledge of neonatal HSE imaging patterns may alert the clinician to the proper diagnosis.