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New Treatments for Inflammatory Bowel Disease

Definition

Inflammatory bowel disease consists of ulcerative colitis and Crohn's disease. Ulcerative colitis is an idiopathic disorder characterized by inflammation limited to the mucosal layer of the colon, almost invariably involving the rectum and extending in a proximal and continuous fashion to involve other portions of the colon. Crohn's disease is characterized by transmural rather than superficial inflammation involving the entire bowel wall from mucosa to serosa. This transmural inflammatory process gives rise to fibrosis and the obstructive clinical presentations which are common and not seen often in ulcerative colitis. In addition, as part of the transmural inflammatory process, sinus tracts burrow through and penetrate the serosa, giving rise to microperforations and fistula, which are also part of the clinical picture of Crohn's disease. Unlike ulcerative colitis, which is limited to the colon, Crohn's disease may involve the entire gastrointestinal tract from mouth to perianal area. About 80% of patients have small bowel involvement, usually in the distal ileum, with one third of patients having ileitis alone. Approximately 50% of patients will have both ileal and colonic involvement, so-called ileocolitis; and 20% will have disease limited to the colon. In those cases, about Lesser numbers will have involvement of the esophagus and proximal disease.

Epidemiologic, Etiologic and Pathophysiologic Features

Although both diseases have a worldwide distribution, the incidence is highest in developed areas including North America, northern Europe and, to a lesser extent, South Africa and Australia. They tend to occur in northern areas of a given country. These disorders tend to be diseases of younger people, with peak incidence occurring in the late teens and early 20s up to age 40. Nonetheless, it should be recognized that both ulcerative colitis and Crohn's disease may occur for the first time in older patients, and There is a clear familial pattern of inflammatory bowel disease, in that 10 to 25% of patients who develop either ulcerative colitis or Crohn's disease will have a close relative who also has a form of inflammatory bowel disease; and there tends to be a strong concordance for disease category.