Probable HHV-6 limbic encephalitis after liver transplantation: diagnostic overlap with tacrolimus neurotoxicity and refractory status epilepticus

Abstract

Human herpesvirus 6 (HHV-6) encephalitis is an uncommon but severe post-transplant complication. A 64-year-old woman developed confusion, behavioural changes, and staring episodes 6 months after liver transplantation. Cerebrospinal fluid (CSF) multiplex testing was positive for HHV-6, and magnetic resonance imaging showed bilateral hippocampal and mesial temporal abnormalities, later involving the bitemporal and insular regions. Her course was complicated by refractory status epilepticus, cardiac arrest, kidney injury, prolonged ventilation, pancytopenia, recurrent HHV-6 positivity, and death. This case highlights the challenge of interpreting CSF HHV-6 positivity amid competing diagnoses and the treatment burden imposed by antiviral and antiseizure drug toxicity.