colitis

n.

inflammation of the colon. The usual symptoms are diarrhoea, sometimes with blood and mucus, and lower abdominal pain. It is diagnosed by demonstrating inflammation of the colon's lining (mucosa) by sigmoidoscopy or barium enema X-ray. Colitis may be due to infection by Entamoeba histolytica (amoebic colitis) or by bacteria (infective colitis); it may also occur in Crohn's disease (Crohn's colitis). Partial or temporary cessation of blood supply to the colon may cause ischaemic colitis. Ulcerative colitis (idiopathic proctocolitis) almost always involves the rectum (see proctitis) as well as a varying amount of the colon, which become inflamed and ulcerated. Its cause is unknown. It varies in severity from month to month, relapses being treated by drugs, including corticosteroids and drugs containing 5-aminosalicylic acid (sulfasalazine, mesalazine, and olsalazine, as tablets or enemas), and bed rest. Severe, continuous, or extensive colitis may be treated by surgery (see colectomy, proctocolectomy). Diarrhoea or pain where inflammation is absent is often due to mucous colitis (see irritable bowel syndrome).