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Colitis (cont.)

6 common causes of colitis

Inflammation of the colon can be caused by a variety of illnesses and infections. Some of the most common causes are discussed in the next few sections.

1. Infectious Colitis

  • Viruses and bacteria can cause colon infections. Most are food-borne illnesses or "food poisoning." Common bacterial causes of food borne infection include Shigella, E Coli, Salmonella and Campylobacter. These infections may cause bloody diarrhea and can result in significant dehydration.
  • Parasite infections such as giardia also can cause significant diarrhea. The parasite can enter the body when infected water is swallowed. The source may be from recreational water such as rivers, lakes, and swimming pools. It also may be contaminated water from a well or cistern.
  • Pseudomembranous colitis is caused by the bacteria Clostridium difficile (C. difficile). This disorder is often seen in patients who have recently been taking antibiotics for an infection or have been admitted to the hospital. The antibiotic alters the normal bacteria present in the colon that helps with digestion and allows an overgrowth of the Clostridium bacteria. Clostridium bacteria produce a toxin that causes diarrhea. This is an infection, and often there is a fever present. The diarrhea is usually not bloody.

2. Ischemic Colitis

  • The arteries that supply blood to the colon are like any other artery in the body. They have the potential to become narrow due to atherosclerosis (just like blood vessels in the heart, which can cause angina, or narrowed vessels in the brain can cause a stroke). When these arteries become narrow, the colon may lose its blood supply and become inflamed.
  • The colon can also lose its blood supply for mechanical reasons. A couple of examples include volvulus, where the bowel twists on itself, or an incarcerated hernia, where a portion of the colon gets trapped in an outpouching of the abdominal wall, which prevents blood from flowing to the affected portion.
  • In individuals who are at risk for decreased blood flow to the colon, ischemic colitis can occur if the blood pressure falls. This may occur with dehydration, anemia, or shock.
  • Ischemia or lack of blood supply causes significant pain, fever, and bloody bowel movements.
  • Blood clots can also travel or embolize to block an artery and decrease blood flow to the bowel. Individuals who have the common heart rhythm disturbance, atrial fibrillation, are at risk of forming small clots in the heart, which break off and block the blood supply to the bowel. This is the same mechanism that can cause a stroke or TIA (transient ischemic attack) if the blockage occurs in an artery that supplies the brain.
Medically Reviewed by a Doctor on 6/20/2016

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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).

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