Abstract
Hemorrhagic cystitis (HC) refers to the selective involvement of the urinary bladder by an inflammatory condition due to an infectious or non-infectious etiology. Hemorrhagic cystitis is a common cause of morbidity and mortality in patients undergoing stem cell transplant (SCT). Hemorrhagic cystitis post-SCT is classified into early onset or late or delayed onset. Early-onset hemorrhagic cystitis is caused mostly by cyclophosphamide administration and appears to be caused by acrolein. BK virus infection is the most common infective cause of hemorrhagic and non-hemorrhagic cystitis. BK virus can be detected in both blood and urine.