Hemorrhagic cystitis in a cohort of pediatric transplantations: incidence, treatment, outcome, and risk factors.

Hemorrhagic cystitis (HC) can be a severe complication in hematopoietic stem cell transplantation (HSCT). To identify risk factors and etiology and to improve treatment, a number of factors were analyzed retrospectively in a cohort of 74 consecutive pediatric HSCTs between 2007 and 2009 in a single institution. The 74 transplantations were done in 67 children. Potential risk factors for HC were age, gender, underlying disease, ablative conditioning, graft-versus-host disease prophylaxis, unrelated donor, stem cell source, conditioning regime, acute graft-versus-host disease and cytomegalovirus reactivation. Fourteen patients developed HC (19%). In all but 4 cases (71%), HC appeared after engraftment. Severity was assessed as grade 1 in 1, grade 2 in 8, and grade 3 in 5 cases. In 79% of the patients with HC, urine samples showed BK virus. This may provide guidance for future prevention policies. In 11 children, treatment included forced hydration, spasmolytics, and bladder irrigation. Three children required cystoscopy, intravesical therapy and/or antiviral therapy. Statistical analysis revealed age over six years to be a risk factor for the development of HC. We conclude that current conditioning regimens lead to a still considerable incidence of HC in pediatric HSCT, necessitating the evaluation of screening protocols and preventive measures.