Crohn disease

Also known as regional enteritis, regional ileitis, granulomatous colitis, or transmural colitis, this disease is one of the inflammatory bowel diseases.

It is different from ulcerative colitis, with which it can be confused, in several major respects. First is that Crohn disease tends to extend completely through the intestinal wall, whereas ulcerative colitis is limited (except in the case of toxic megacolon) to the surface mucous membrane of the bowel. Next is that Crohn disease is segmental, often with areas of normal bowel interspersed with diseased bowel; ulcerative colitis begins in the rectum and extends up the colon in a solid wave of diseased bowel mucosa. Crohn disease can affect any segment of the gastrointestinal tract, from the mouth to the anus; ulcerative colitis affects only the colon.

Crohn disease most often presents in childhood as disease of the last segment of the small bowel, the ileum (hence ileitis). Almost as many children present with both ileal and colonic disease. Only about one in ten children have purely colonic disease when first diagnosed. Children with ileocolitis typically have crampy, abdominal pain and diarrhea, sometimes with blood. Growth failure may precede other symptoms by one or two years and is twice as likely to occur with Crohn disease than with ulcerative colitis. In contrast to ulcerative colitis, perianal disease is common (tags, fistulas, abscesses).

Diagnosis of Crohn disease is by a combination of history review, physical exam, evaluation of lab studies to rule out other causes of ileitis and colitis, x-ray studies and direct endoscopic visualizaton and biopsy of the gut. Treatment is a complex issue because of the variability of the disease both in its manifestations and its natural course in a given patient. Steroids figure prominently in treatment; other immunosuppressive medications are sometimes necessary. Surgical treatment is reserved for complications such as critical narrowing of the gut (stricture with small bowel obstruction), localized unresponsive disease of small bowel or colon, bowel perforation, and intractable bleeding.