Inflammation of the lining of the colon. Colitis may affect the entire colon or only parts of it. One type of colitis is caused by bacterial infection. Sometimes, this form of the disease occurs after treatment with antibiotics and is treated with another type of antibiotic. A more serious type of colitis, ulcerative colitis, shares many similarities with Crohn disease, and both disease are considered types of Inflammatory Bowel Disease.
The most common symptom of colitis is blood in the feces. An attack of diarrhea that contains blood and pus is a typical sign of colitis. Other symptoms may include abdominal pain, persistent diarrhea, fever, and weight loss. An anal fissure (a tear or ulcer in the lining of the anal canal), an anal fistula (an abnormal channel between the anal canal and a hole in the skin surrounding the anus), or an abscess in the anal canal an also develop.
Colitis is diagnosed by a complete physical examination and tests, such as stool analysis, blood tests, a lower Gastrointestinal (GI) series (an x-ray procedure also called a barium enema), sigmoidoscopy and colonoscopy. In sigmoidoscopy and colonoscopy, the colon and rectum are examined by using a slim, flexible, lighted tube inserted through the anus. The colonoscopy (endoscopy of the entire colon) is a more extensive procedure than the sigmoidoscopy (an endoscopy of the rectum and sigmoid colon). A biopsy (analysis of a tissue sample) can confirm the presence of ulcerative colitis.
Source: AMA Complete Medical Encyclopedia, Copyright 2003, American Medical Association