One complication of transmural inflammation with Crohn disease is fistula formation. Seen here is a fissure extending through mucosa into the submucosa toward the muscular wall, which eventually will form a fistulous tract. Fistulae can form between loops of bowel, bladder, and even skin. With colonic involvement, perirectal fistulae are common. |
Use of biologic agents such as adalimumab and infliximab, which are monoclonal antibodies targeting tumor necrosis factor (TNF), has improved therapy for Crohn disease. A biologic agent plus the immunosuppressant azathioprine can be effective in diminishing the inflammation and tissue destruction, with reduction in complications. |