Herpes simplex is a common cause of viral encephalitis, and can present as one or combination of more than one clinical features.

1. Clinical Features:

Generalized features including fever, headache, psychiatric symptoms such as hallucinations, delusions etc. seizures and vomiting.

Focal neurological lesions such as cranial nerve lesions in isolation or combination, hemiplegia or hemiparesis, aphasia etc.

2. Etiopathogenesis:

Most commonly herpes simplex type 1 causes encephalitis and accounts for almost 95 % of cases of herpes simplex encephalitis.

It characteristically attacks medial temporal and inferior frontal lobes of cerebral hemispheres.