Inflammatory Bowel Disease

In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan.


Inflammatory bowel disease (IBD) is characterized by repetitive episodes of inflammation of the gastrointestinal tract caused by an abnormal immune response to gut microflora. Inflammatory bowel disease encompasses two types of idiopathic intestinal disease that are differentiated by their location and depth of involvement in the bowel wall. Ulcerative colitis (UC) involves diffuse inflammation of the colonic mucosa. Most often, UC affects the rectum (proctitis), but it may extend into the sigmoid (proctosigmoiditis), beyond the sigmoid (distal ulcerative colitis), or include the entire colon up to the cecum (pancolitis). Crohn disease (CD) results in transmural ulceration of any portion of the gastrointestinal tract (GI), most often affecting the terminal ileum and colon. Both diseases are classified by extent (mild, moderate, or severe) and location. CD also is classified by phenotype- inflammatory, stricturing, or penetrating.

Besides the GI tract, both Crohn disease and ulcerative colitis have many extraintestinal manifestations. While in most patients, the disorders can be distinguished, in at least 10% of patients, the features are so similar that it is not possible to initially differentiate between the two disorders.

Both disorders have a genetic predisposition; neither is curable, and they both carry enormous morbidity. Finally, both increase the risk of colorectal cancer.

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