Human Herpes Virus 6 Encephalitis Following Bone Marrow Transplantation with Uncommon Magnetic Resonance Imaging Findings

Human Herpes Virus 6 (HHV6) is known to be commonly associated with encephalitis related to immunosuppression and transplantation, and to bone marrow transplantation (BMT) in particular.1 HHV-6 is known to be common in transplant recipients and lead to several clinical manifestations, such as encephalitis.1-4 HHV 6 encephalitis in patients with BMT is known as latent infection. The first such case was reported in 1994.5 HHV6 encephalitis in patients receiving immunosuppressant drugs following BMT has various clinical manifestations, suggesting the involvement of the medial temporal lobe. These include confusion, seizure, and amnesia, which lead to so-called post-transplant acute limbic encephalitis.3 Neuroimaging findings in patients with HHV6 encephalitis correspond to those found in patients with acute limbic encephalitis.3,6-8 However, cases of HHV6 encephalitis with hippocampal atrophy and glucose hypometabolism have very rarely been reported.