Varicella-zoster virus limbic encephalitis in an immunocompromised patient

A case of limbic encephalitis in a patient who had undergone prolonged immunosuppressive treatment with i.v. cyclophosphamide and oral prednisolone for a microscopic polyangeitis is reported. A brain MRI scan revealed symmetric mesial temporal lobe lesions. Studies of cerebrospinal fluid (CSF) revealed a positive PCR for varicella-zoster virus (VZV) DNA in 2 separate samples. Owing to a delay in diagnosis, intravenous acyclovir was initiated only after 11 d of symptoms. PCR of CSF for VZV DNA became negative on day 14 of treatment while brain lesions had resolved on subsequent MRI scans. Limbic encephalitis is a novel form of VZV infection. When brain imaging is suggestive of limbic encephalitis in an immunocompromised patient, PCR of CSF for VZV DNA should be performed, as early antiviral treatment may improve the outcome.