Sudden unexpected death associated with HHV-6 in an adolescent with tuberous sclerosis

A 14-year-old female with tuberous sclerosis and history of seizures was fo und dead in bed at home 3 days after she had been assessed as doing well at a routine neurology clinic appointment. She had been treated with an antie pileptic drug, felbamate, for 36 months and had been seizure-free except fo r one seizure episode 5 months before death. Postmortem examination reveale d cerebral edema, with uncal and tonsillar herniation, and pulmonary edema, consistent with seizure-induced apnea, Multiple microglial nodules with ma ture perivascular lymphocytic cuffing and diffuse infiltrates were identifi ed around subependymal tuberous sclerosis giant cell nodules, Immunostainin g and electron microscopy revealed human herpesvirus-6-infected macrophages , astrocytes, lymphocytes, and endothelial cells in the subependymal tubero us sclerosis lesions and choroid plexus, Subacute human herpesvirus-6 encep halitis is postulated to have precipitated a seizure and thus sudden unexpe cted death in epilepsy in this otherwise stable adolescent patient. (C) 199 9 by Elsevier Science Inc. All rights reserved.