Summary contentEducational Objective: to review the incidence, the diagnosis, the optimisation of the patient, and the treatment of entero-urinary fistulas in Crohn’s disease.
Historically, abdominal fistulas had an incidence of 35% in Crohn’s Disease (CD) patients. In recent series from Referral Centres, the incidence reported has been as high as of 56% for small bowel locations, and 61% in colonic disease. Urinary fistulas, involving the bladder and the ureter, have a reported incidence of 8-20%. However, in the last decade, the prevalence in large population studies, is inferior to 2%, and it is typical of male gender (75%). In the CD – Clinical Auditing and Research Database (CD-CARD) of “Luigi Sacco” University hospital, among the 1272 patients with 2249 intestinal locations, 908 enteric fistulas were identified, 42 of which were entero-urinary. 86% were entero-vesical and 14% entero-ureteral fistulas. 69% were treated by laparoscopic, and 31% by open surgery, with a cumulative incidence of 5%. Diagnosis of entero-urinary fistulas is based on cross-sectional imaging. Gastro-intestinal Ultrasonography (GI-US), CT scan, and MRI has a sensitivity of 75-80%, that rise to 97% if GI-US is combined with CT scan or MRI. Medical therapy, based of Anti-TNFa is indicated in the presence of inflammatory pattern, with a 45% rate of fistula closure. Surgical treatment is based on the postpone-and-optimize strategy: urine culture and target antibiotic therapy, abscess drainage if present, nutritional improvement, and drug tapering. Preoperative ureteral stenting is indicated when the fistula involves the ureter or the vesical trigon or neck. Laparoscopic approach is indicated whenever technically feasible.