A Rare Case of Human Herpesvirus 6 Meningitis in an Immunocompetent Adult Presenting With Recurrent Encephalopathy: Could Prior Head Trauma or an Incidental Cerebral Cavernous Malformation Be a Predisposing Factor?

Human herpesvirus 6 (HHV-6) meningitis/encephalitis is typically seen in immunocompromised patients, with rare reports in immunocompetent adults. We present the case of a 52-year-old immunocompetent man with recurrent acute encephalopathy and incidental cerebral cavernous malformation (CCM), alongside a remote history of traumatic brain injury (TBI). Cerebrospinal fluid (CSF) analysis and multiplex polymerase chain reaction (PCR) test confirmed HHV-6 infection, with neuroimaging showing leptomeningeal enhancement. This case suggests that structural brain abnormalities such as CCM and prior TBI may cause chronic blood-brain barrier (BBB) disruption, facilitating HHV-6 neuroinvasion even in the absence of immunosuppression. Awareness of such predisposing factors is crucial for the timely diagnosis and treatment of HHV-6 meningitis/encephalitis in immunocompetent individuals. Further research is needed to clarify the pathophysiological link between BBB dysfunction and HHV-6 central nervous system (CNS) infection.