Basal ganglia involvement in a child with herpes simplex encephalitis.

Herpes simplex encephalitis (HSE) is a leading cause of sporadic, nonepidemic viral encephalitis in children and adults. We report a very rare case of HSE with involvement of bilateral thalamus, putamen, upper pons and midbrain, with development of extrapyramidal symptoms which responded to corticosteroid therapy. A 15-mth-old female baby admitted with complaint of fever for 5 days and generalised tonic clonic seizure 10 hours before admission. On clinical examination patient was drowsy, temperature was 39.4 degrees C and vitals were stable with signs of increased intracranial tension. There were no signs of meningeal irritation. Patient gradually become unconscious in the next few hours and pupils were constricted bilaterally with development of atonia in all four limbs and neck muscles. Doll's eye phenomenon was absent.