Age-related features of HHV-6 central nervous system infection

Abstract

Objective: Our goal is to describe the clinical, biological, neurophysiological and brain Magnetic Resonnance Imaging (MRI) features, as well as outcome, of Human Herpes 6 (HHV-6) acute neurological infection in immunocompetent children. Methods: We retrospectively analyse the data of all paediatric patients referred to Nancy Academic Children Hospital between January 2007 and June 2015 for acute neurologic symptoms who exhibit positive HHV-6 DNA polymerase chain reaction (PCR) in cerebrospinal fluid (CSF). Results: Fifteen patients are included. Eight children are under the age of 2. They exhibit clinical encephalitis, associated with white-matter T2 hyper-intensities on early MRI in 5 cases. Three of these patients evolve with clinical sequelae: epilepsy (n=2), hemiparesis (n=1) or learning disabilities (n=2). The 7 other patients are aged of 2 to15. They initially present clinical signs of cranial nerve neuritis (n=4), febrile meningitis (n=3), febrile encephalitis (n=1). Only 1 of them exhibits brain MRI abnormalities consistent with 2nd cranial nerve neuritis. All children over the age of 2 recover completely. Conclusion: This is the first study to describe the age related presentation and outcome of CNS HHV-6 primary infection. Encephalitis that may lead to neurological sequelae concerns younger children. Neuritis is the most common clinical presentation after the age of 2. Management of antiviral therapies remains to be determined.