[Treatment of fistulizing Crohn's disease]

The treatment of fistulating Crohn's disease should include a combined medical and surgical approach and should be defined on an individual basis. Asymptomatic enteroenteric fistulas usually require no treatment, but internal fistulas (gastrocolic, duodenocolic, enterovesical) that cause severe or persistent symptoms require surgical intervention. While low asymptomatic anal-introital fistula may not need surgical treatment, in case of a symptomatic enterovaginal fistula surgery is usually required. There are no controlled-randomized trials to assess the effect of medical treatment for non-perianal fistulating Crohn's disease. The incidence of perianal fistulae varies according to the location of the disease, with its occurrence varying between 21-23%. The diagnostic approach should include an examination under anesthesia, endoscopy, and either MRI or EUS before the treatment begins. Asymptomatic simple perianal fistulas require no treatment. The presence of a perianal abscess should be ascertained and if present should be drained urgently. In case of a complex perianal disease, seton placement should also be recommended. Antibiotics (metronidazole and ciprofloxacine) are useful for treating complex perianal disease, however, when discontinued, most of the fistulas relapse. The current consensus suggests that azathioprine/6-mercaptopurine is the first line medical therapy for complex perianal disease, which is always given in combination with surgical therapy (seton, fistulotomy/fistulectomy). Anti TNF-alpha agents (infliximab and adalimumab) should be used as a second choice medical treatment. In refractory and extensive complex perianal disease a diverting stoma or proctectomy should be performed.