Chronic inflammation of the gastrointestinal (GI) tract. Crohn’s disease can affect any part of the GI tract but most commonly involves the small intestine and the beginning of the large intestine, causing diarrhea, abdominal cramping and pain, and weight loss. Crohn’s disease appears to have multiple causes. Scientists believe that bacteria, viruses, and possibly fungi may provoke an autoimmune attack in which the body’s immune system mistakenly attacks the inner lining of the small intestine. The disease sometimes runs in families. Some studies suggest that nonsteroidal anti-inflammatory drugs (NSAIDs), antibiotics, oral contraceptives, or a high-fat diet may significantly increase the risk of Crohn’s disease.
The condition is treated with medications, bowel rest, and surgery, if needed. Medications called aminosalicylates (such as balsalazide, mesalamine, olsalazine, and sulfasalazine) are used to treat inflammation in newly diagnosed patients with mild symptoms. Corticosteroids (budesonide, hydrocortisone, methylprednisone, and prednisone) may decrease inflammation in those with moderate to severe symptoms. Immunomodulators such as 96-mercaptopurine (or 6-MP), azathrioprine, cyclosporine, and methotrexate reduce immune activity and inflammation. Biologic therapies (adalimumab, certolizumab, infliximab, natalizumab, and vedolizumab) target an immune system protein that promotes inflammation. Other medications include acetaminophen for mild pain, antibiotics for infection, and loperamide for severe diarrhea. The patient sometimes needs to rest his or her bowel for a few days to several weeks by drinking only clear liquids or having no oral intake. In up to one-fifth of patients, surgery may be needed.