Radiation colitis is inflammatory bowel damage due to the exposure to radiation energy. Its special subtype is the radiation proctitis, which is an inflammation of the rectal mucosa.
The inflammatory response occurs as a response to mucosal damage by the radiation. The radiation is more aggressive to cells that frequently multiply such as the cells of gastrointestinal mucosa. The most typical cause of intestinal radiation damage is local radiotherapy of pelvic tumors (such as prostate cancer in men and cervical cancer in women).
Acute symptoms occur within a week after the exposure. They include diarrhea, sudden urge to defecate and the presence of blood in stool. The inflammation gradually moves into the chronic phase with pain during defecation and occasional findings of blood in the stool. Chronic inflammation may lead to formation of intestinal fistulas and narrowing of the intestines.
The diagnosis is highly probable in patients suffering from the mentioned symptoms, who have a personal history of recent radiotherapy. The main diagnostic method is a colonoscopy, which allows visualizing the extent and severity of mucosal damage and which enables the doctor to take tissue samples for a histological examination.
The condition is difficult to treat. Adequate fluid intake is necessary to prevent dehydration by diarrhea and some medications can be administered to slow the bowel movements. Local anti-inflammatory drugs may be prescribed, for example the corticosteroids. Endoscopic therapy is very efficient as the doctor may burn the bleeding sites during the colonoscopy by a special argon-coagulation probe. Local complications as the fistulas and strictures may be treated surgically, but it should be kept in mind that any wounds in irradiated areas have a reduced ability to heal.