Gastrointestinal Conditions: Inflammatory Bowel Disease

Inflammatory bowel diseases (IBDs) comprise a group of conditions thought to be caused by a dysregulated host immune response to the gut microbiome. IBDs, which affect 1.3% of Americans, include Crohn disease (CD), ulcerative colitis (UC), and microscopic colitis. UC and microscopic colitis are limited to the colon, but CD can occur anywhere along the gastrointestinal tract. Gastrointestinal symptoms typically predominate, including diarrhea and abdominal pain, along with systemic symptoms of weight loss, fatigue, night sweats, and fever. However, many patients have extraintestinal symptoms, often in the joints, skin, or eyes; extraintestinal symptoms can appear before gastrointestinal symptoms. Colonoscopy with biopsy is the test of choice for diagnosing UC and microscopic colitis. Diagnosing CD typically requires ileocolonoscopy and also may require esophagogastroduodenoscopy. Traditionally, therapy involved mesalamine for UC, thiopurines or methotrexate for CD, and budesonide for microscopic colitis. However, recently, biologic drugs targeting tumor necrosis factor alpha and other inflammatory drugs have revolutionized care of IBD. Surgery (complete resection of involved colon) can be curative in UC. In CD, surgery typically is only used for complications or refractory disease.