Abstract
The BK virus is a polyomavirus known to particularly affect transplant recipients. An important complication caused by BK virus infection in bone marrow transplant patients is hemorrhagic cystitis. We present a 31-year-old male with a history of bone marrow transplantation complicated by graft-versus-host disease (GVHD) and was diagnosed with BK virus-related hemorrhagic cystitis. He presented with gross hematuria and suprapubic and penile pain for one week. He has a significant past medical history of acute B-cell lymphocytic leukemia for which he has successfully undergone allogenic bone marrow transplantation, which was complicated by GVHD. Imaging revealed significant bladder wall thickening which prompted an evaluation for BK virus-induced hemorrhagic cystitis. A urinary specimen was sent for BK virus polymerase chain reaction (PCR) which was strongly positive, confirming the infection. He was managed supportively throughout his hospitalization and improved with symptomatic management alone. Our case demonstrates one of the main complications caused by the BK virus in allogeneic bone marrow transplant patients in the setting of GVHD and is an important differential to keep in mind when treating patients presenting with hematuria after bone marrow transplantation.