Colitis is swelling (inflammation) of the large intestine (colon).

Colitis can have many different causes, including:

• Infections, including those caused by a virus, parasite, and food poisoning due to bacteria
• Inflammatory disorders (ulcerative colitis and Crohn's disease)
• Lack of blood flow (ischemic colitis)
• Past radiation to the large bowel

See also:

• CMV colitis
• Cryptosporidium enterocolitis
• Necrotizing enterocolitis
• Pseudomembranous colitis

Symptoms can include:

• Abdominal pain and bloating that is constant or comes and goes
• Bloody stools
• Chills
• Constant urge to have a bowel movement
• Dehydration
• Diarrhea
• Fever

The health care provider will perform a physical exam and ask questions about your symptoms, including:

• How long you have had the symptoms
• How severe your pain is
• How often it occurs
• How long it lasts
• How often you have diarrhea
• Whether you have been traveling

The health care provider can diagnose colitis by inserting a flexible tube into the rectum (flexible sigmoidoscopy or colonoscopy) and evaluating specific areas of the colon. Biopsies taken during these tests may show changes related to inflammation.

Other studies that can identify colitis include:

• Abdominal CT scan
• Abdominal MRI
• Abdominal x-ray
• Barium enema

Treatment is directed at the cause of disease (infection, inflammation, lack of blood flow, or another cause).

See the conditions listed above for specific recommendations.

The prognosis varies with each disease. See particular conditions listed above.

• Bleeding
• Hole in the colon
• Toxic megacolon
• Sore (ulceration)

Call your health care provider if you have symptoms such as:

• Abdominal pain that does not get better
• Blood in the stool or stools that look black
• Diarrhea or vomiting that does not go away
• Swollen (distended) abdomen

Prevention depends upon the cause of colitis. See the specific condition.