BK Virus Encephalitis: Case Report, Review of the Literature, and Description of a Novel Treatment Modality

Objective: To describe a case of BK virus encephalitis with attempted direct antiviral therapy, review the reported cases of BK virus in the central nervous system, and report the novel use of intravenous cimetidine in place of oral probenecid to minimize the toxicities of intravenous cidofovir. Case Summary: A 36-year-old male with acute myelomonocytic leukemia and subsequent myelodysplastic syndrome underwent allogeneic hematopoietic stem cell transplant. His course was complicated by severe graft-versus-host disease involving his skin and gastrointestinal tract. Five weeks after transplantation, he developed fever and confusion. Magnetic resonance imaging was suggestive of limbic encephalitis and cerebrospinal fluid tested positive for BK virus. Therapy with intravenous cidofovir was thought to be indicated. Although probenecid is commonly used to minimize the toxicities of cidofovir, the patient’s severe graft-versus-host disease raised concerns about absorption of oral medications. Based on animal mo...