Inflammatory bowel diseases (IBD) are those that cause inflammation in the intestines. One of these is Crohn's disease, which usually affects the lower part of the small intestine, called the ileum. While Crohn's disease is characterized by ulcerations of the intestines, it can affect any other part of the digestive system as well. Also known by various other names such as granulomatous enteritis or colitis, Crohn's disease is not easily diagnosed since its symptoms resemble those of other IBD. The inflammation causes abdominal pain and often results in diarrhea. Other symptoms include persistent rectal bleeding, weight loss and fever. Crohn's disease causes the intestinal wall to swell, resulting in blockage of the intestine. It causes ulcers that can tunnel into and affect surrounding tissues such as the bladder, vagina, or even the skin. These tunnels, or fistulas, can become infected and may require surgery. Crohn's disease also results in nutritional deficiencies resulting from a poor diet or intestinal loss of protein. Patients suffering from Crohn's disease may also develop complications such as arthritis, skin problems, kidney stones, and inflammation in the eyes or mouth. There are various theories about what causes Crohn's disease. The common opinion is that the inflammation in the intestine is caused by the reaction of the body's immune system to a virus. The disease is believed to run in families and affects both men and women. As of now there is no cure for Crohn's disease. Treatment includes measures to reduce inflammation, rectify nutritional deficiencies, and relieve other symptoms. Crohn's disease is chronic and patients may require medical care over a long period, though some may experience periods of remission. Some patients need surgery to deal with blockages or abscesses in the intestine. Patients with Crohn's disease in the large intestine might require surgery to remove their entire colon, while others only need to have the diseased part removed. Crohn's disease may not reoccur in some patients for long periods of time and they can continue to function normally at work and at home.