Thalamic involvement in HSV type 1 encephalitis in children

Abstract

Herpes simplex virus (HSV) type 1 frequently causes fulminant encephalitis and it is the most common etiological agent for sporadic encephalitis in the developed world. We report a case of HSV encephalitis in a 7-month-old infant with bilateral thalamic involvement. Thalamic involvement has been reported in HSV encephalitis, more commonly in infants and young children compared to adults. But the implications of thalamic involvement in HSV encephalitis are not clearly known. Using Medline, we reviewed all the published pediatric cases of HSV encephalitis with thalamic involvement. Twenty-nine cases met our inclusion criteria. Out of 30 patients (including our patient), 14 patients had bilateral thalamic involvement and 16 had lesion on one side. Ten patients had at least one relapse. Six of them developed movement disorder. One patient died, two had complete recovery of the symptoms but majority of the patients developed neurological sequelae.