Patients with ulcerative colitis limited to the rectum (proctitis) or colitis limited to the end of the left colon (proctosigmoiditis) usually do quite well.
Brief periodic treatments using oral medications or enemas may be sufficient. Serious complications are rare in these patients. In those with more extensive disease, blood loss from the inflamed intestines can lead to anemia, and may require treatment with iron supplements or even blood transfusions. Rarely, the colon can acutely dilate to a large size when the inflammation becomes very severe. This condition is called toxic megacolon. Patients with toxic megacolon are extremely ill with fever, abdominal pain and distention, dehydration, and malnutrition. Unless the patient improves rapidly with medication, surgery is usually necessary to prevent colon rupture.
Complications of ulcerative colitis can involve other parts of the body. Ten percent of the patients can develop inflammation of the joints (arthritis).
Some patients have low back pain due to arthritis of the sacroiliac joints. Rarely, patients may develop painful, red, skin nodules (erythema nodosum). Yet others can have painful, red eyes (uveitis, episcleritis). Because these particular complications can risk permanent vision impairment, eye pain or redness are symptoms that require a physician's evaluation. Diseases of the liver and bile ducts may also be associated with ulcerative colitis. For example, in rare patients with a condition called sclerosing cholangitis, repeated infections and inflammation in the bile ducts can lead to recurrent fever, yellowing of skin (jaundice), cirrhosis, and the need for a liver transplant.