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Colitis Overview

Colitis is a term used to describe inflammation of the colon. There are a variety of causes of colitis including infections, poor blood supply (ischemia), and autoimmune reactions.

The colon is located in the abdominal cavity and is divided into the following parts: the cecum, the ascending colon, the transverse, the descending colon, the sigmoid, the rectum, and the anus. The right colon includes the cecum and ascending colon. The left colon includes the transverse segment to the sigmoid.

The colon (large bowel or large intestine) is responsible for collecting and storing the waste products of digestion. It is a long muscular tube that pushes undigested food towards the anus for eventual elimination as a bowel movement. Food is digested in the stomach into a liquid slurry that passes through the small intestine where the nutrients are absorbed into the body for use. When the liquid mixture enters the colon, it mixes with mucus and normal bacteria that reside in the colon. The wall of the colon has numerous layers. There is a smooth muscle layer that wraps the outside and is responsible for squeezing the undigested food through the length of the colon. The inner layer, or mucosa, comes into contact with the fluid and allows the absorption of water and electrolytes, which helps to solidify the feces (poop). The mucosal layer is where the colon inflammation occurs and is responsible for the symptoms of colitis.

As with any other organ, the colon has a blood supply with arteries delivering oxygen rich blood and nutrients to it, and veins that drain carbon dioxide and lactic acid from it. Diseases that decrease blood supply can cause inflammation of the colon.

Picture of the Colon Anatomy and From Areas Where Rectal Bleeding Arises
Picture of the Colon Anatomy and From Areas Where Rectal Bleeding Arises
Medically Reviewed by a Doctor on 5/1/2014
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Colitis Therapy

Featured colitis therapy including diet

  • Diet: Diet is the mainstay therapy for most causes of colitis. A clear fluid diet allows the colon to rest, since the fluid is absorbed in the stomach and none is passed into the colon to be processed as stool.
  • Hydration: Adequate hydration is important because an individual can lose a significant amount of fluid with each diarrheal bowel movement. Aside from the daily fluid requirements, this excess loss needs to be replaced, otherwise dehydration will occur and potentially worsen the symptoms of abdominal pain and cramping.
  • IV fluids: Intravenous (IV) fluid may be required, especially if the patient cannot drink enough fluids by mouth. For some illnesses like ischemic colitis, in which blood flow to the bowel is already compromised, adequate hydration is a key element in treatment.

Read What Your Physician is Reading on Medscape

Colitis »

Colitis is an inflammation of the colon. It may be associated with enteritis (inflammation of the intestine) and/or proctitis (inflammation of the rectum).

Read More on Medscape Reference »

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