Crohn’s Disease

Clinical

Crohn’s disease is an idiopathic inflammatory bowel disease, characterized by chronic inflammation extending through all layers of the intestinal wall and involving mesentery as well as regional lymph nodes. It can manifest anywhere along the GI tract. There is a bimodal incidence peak, with one peak occurring in the second to third decades and the other peak occurring in the eighth decade.  Clinical presentations include abdominal pain, diarrhea, fever, weight loss, and fatigue.  Numerous extraintestinal manifestations are also associated with Crohn’s disease.

Bowel manifestations occur with three anatomic presentations:  small bowel only (30%), colon only (25%), and distal small bowel and colon (45%). Skip lesions are characteristic, with areas of intact mucosa between diseased segments. Ulcerations, both longitudinal and transverse aphthous, arecommon. Endoscopy typically demonstrates a cobblestone appearance. Pathological findings include transmural inflammation with fissures, sinus tracts, abscesses, fistulas, and strictures. Creeping fat, finger-like projections of inflamed/fibrotic mesenteric fat over serosal surface of bowel, is often found at surgery. Histological analysis will demonstrate noncaseating granulomas and crypt abscesses.

Patients with Crohn’s disease have an increased risk of malignancy, which usually occurs at sites of chronic inflammation. Adenocarcinoma is the most common associated malignancy, usually occurring 15-20 years after the onset of disease. There is usually a poor prognosis, as the cancer is often detected at an advanced stage.

Because the entire GI tract can be affected, the first line of treatment is medical management including steroids, aminosalicylates, and immunomodulators for acute exacerbations and maintenance of remission. Surgery is reserved for intractable/fulminant disease, or for complications such as abscesses, strictures, or perforation.