gastrointestinal disorders
Crohn Disease
Key Points
Crohn disease typically affects the ileum and/or colon but spares the rectum (which is invariably affected in ulcerative colitis). Intermittent areas of diseased bowel are sharply demarcated from adjacent normal bowel (called skip areas). Symptoms primarily involve episodic diarrhea and abdominal pain; gastrointestinal bleeding is rare. Complications include abdominal abscesses and enterocutaneous fistulas. Treat mild disease with 5-aminosalicylic acid and/or antibiotics (eg,metronidazole,ciprofloxacin,rifaximin). Treat moderate to severe disease with corticosteroids and sometimes immunomodulators (eg,azathioprine) or biologics (eg,infliximab,vedolizumab,ustekinumab,risankizumab). About 70% of patients ultimately require an operation, typically for recurrent intestinal obstruction, intractable fistulas, or abscesses. 