[Human herpesvirus 6 encephalitis in a patient with glucocorticoid therapy for inflammatory abdominal aortic aneurysm].

A 73-year-old man with inflammatory abdominal aortic aneurysm was admitted with headache and fever. Chest computed tomography (CT) revealed pneumonia and antibiotic therapy was started. Short-term memory impairment was observed and his consciousness had been rapidly deteriorated with seazure. Fluid-attenuated inversion recovery (FLAIR) image and diffusion-weighted magnetic resonance image (DWI) showed high intensity signals around bilateral limbic areas and herpes simplex encephalitis was suspected. After human herpesvirus (HHV)-6 DNA was amplified from cerebrospinal fluid, he was diagnosed with HHV-6 encephalitis and treated with gancyclovir. Clinicians need to be aware that glucocorticoid treatment for elderly can cause HHV-6 encephalitis.