Late-onset BK viral nephropathy in a kidney transplant recipient.

BK polyoma viral infection occurs as an asymptomatic infection in a high proportion of normal hosts without obvious sequelae. In the kidney transplant population, the virus is reactivated because of reduced immunity and, if not appropriately managed, can lead to BK viral nephropathy, which has emerged as a common cause of acute kidney injury and progressive chronic kidney disease in renal transplant recipients. BK viremia almost always occurs during the first 2 years after transplantation, when immunosuppressive therapy is high, or at other periods when immunosuppression is intensified. BK viremia is now detected by routine screening of transplant patients for the first few years, and BK viral nephropathy is considered to be high in the differential diagnosis of acute kidney injury in recently transplanted patients. We report a case of BK viral nephropathy developing 10 years after transplantation and present the challenges of managing advanced disease.