Teaching Neuro Images : Infantile herpes simplex encephalitis

Abstract

A 7-month-old girl developed fever, unconsciousness, and left oral clonic seizures. EEG showed background slowing and periodic lateralized epileptiform discharges (PLED) over right central-temporal regions. Brain MRI revealed a right temporal pole T2 hyperintense lesion (figure 1). CSF PCR was positive for herpes simplex virus 1. Five days after starting treatment with acyclovir (45 mg/kg/day) and phenobarbital (7.5 mg/kg/day), the patient was alert and without seizures, and EEG activity improved. Two weeks later, MRI showed a right temporal-polar malacic area (figure 2), and PCR was negative. Although seen in many diseases,1,2 PLED suggest herpes simplex encephalitis in the appropriate clinical context.