What are intestinal fistulas?
Intestinal fistulas are tubular connections between the bowel and other organs or the skin. Fistulas form when inflammation extends through all of the layers of the bowel and then proceeds to tunnel through the layers of other tissues. Accordingly, fistulas are much more common in Crohn’s disease than in ulcerative colitis. (In the latter, as you recall, the inflammation is confined to the inner lining of the large intestine.) Fistulas often are multiple. They may connect the bowel to other loops of the bowel (enteroenteric fistulas), to the abdominal wall (enterocutaneous), to the skin around the anus (perianal), and to other internal locations such as the urinary bladder (enterovesical), vagina (enterovaginal), muscles, and scrotum. In Crohn’s disease patients, fistulas may form in conjunction with intestinal strictures. One reason for this association is that both fistulas and strictures can begin with inflammation of the entire thickness of the bowel wall (transmural inflammation).
