Cidofovir bladder instillation for the treatment of BK hemorrhagic cystitis after allogeneic stem cell transplantation.

We report a case of severe hemorrhagic cystitis after allogeneic transplantation in association with high BK viral load. After failure of aggressive hydration, platelet and blood transfusions, continuous bladder irrigation, and tapering of the immune suppression, we instilled cidofovir into the bladder, which resulted in decreased BK viral load and significant clinical improvement. Our case suggests that local cidofovir therapy for viral hemorrhagic cystitis is effective and well tolerated with no observed side effects.