Crohn's Disease

1. Epidemiology -- 3-7 per 100,000. Highest in: N. Am. & N. Europe. Bimodal: teens/twenties and 50s. Smoking: 2x risk. First deg. relative: 13x risk. Sibling: 30x risk.

2. Pathophys -- Unknown etiology: Infectious/Immunologic/Genetic? Causes transmural ulceration of any GI mucosa (lips to anus). 30% small int. 15% large int. 55% both. Skip lesions, fat wrapping, transmural inflammation, internal fistulae. Microscope: classic "noncaseating granuloma."

3. Presentation -- Young adult, episodes of abd pain/diarrhea. Rare to have blood/mucus in stool. Low-grade fever, weight loss, malaise. Recurrent anal fissure/fistula/abscess. Extraintestinal: erythema nodosum, pyoderma gangrenosum, uveitis, iritis, joint pain, others.

4. Workup -- Look for lesions in mouth, on rectal exam. Check skin, eyes, joints. Common tests: barium enema, endoscopy. CT scan used often, too. Labs: cbc, chem 7, LFT, stool: guaiac, O&P, fecal leukocytes. R/O infectious gastroenteritis, pancreatitis, diverticulitis. Distinguish Crohn's from UC (often difficult).

5. Treatment Options -- No cure. Sulfasalazine, mesalamine for control. Steroids for flare-ups. Operate for: obstruction, perforation, fistula, bleeding, cancer. Resect only diseased bowel, larger margins don't help. Strictureplasty instead of resection can help prevent short-gut syndrome. Try not to operate for: perianal disease.

6. Complications -- Natural history includes obstruction/perforation. Recurrence is common. Risk for cancer 100x higher than general pop.

7. Outcomes -- Operations not curative. Lesions recur 70% after 1 yr. 85% after 3 yrs. Second operation needed in 45% of patients. Of those, 25% will need a third operation. (90% of Crohn's patients operated on never need more than a second operation). Death rate for Crohn's patients 2-3x higher than general pop.

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