HSV encephalitis typically produces abnormal signal +/- enhancement in the limbic system and temporal lobes. It is usually bilateral but asymmetrical. The basal ganglia are usually spared. The differential diagnoses include limbic encephalitis (paraneoplastic), gliomatosis cerebri, and status epilepticus. HSV-1 causes 95% of all herpetic encephalitides. Mortality ranges from 50-70%, and treatment is with intravenous antivirals.

Osborn A, et al. Diagnostic Imaging: Brain. Amirsys 2004