Varicella-Zoster virus limbic encephalitis in an immunocompromised patient

A case of limbic encephalitis in a patient who had undergone prolonged immu nosuppressive treatment with i.v. cyclophosphamide and oral prednisolone fo r a microscopic polyangeitis is reported. A brain MRI scan revealed symmetr ic mesial temporal lobe lesions. Studies of cerebrospinal fluid (CSF) revea led a positive PCR for varicella-zoster virus (VZV) DNA in 2 separate sampl es. 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 o f treatment while brain lesions had resolved on subsequent MRI scans. Limbi c encephalitis is a novel form of VZV infection. When brain imaging is sugg estive of limbic encephalitis in an immunocompromised patient, PCR of CSF f or VZV DNA should be performed, as early antiviral treatment may improve th e outcome.