Rectal Bleeding (cont.)

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How is the cause and site of rectal bleeding determine?

An accurate diagnosis of the location and the cause of rectal bleeding is important for proper treatment. Diagnosis with relies on the history and physical examination, anoscopy, flexible sigmoidoscopy, colonoscopy, radionuclide scans, angiograms, and blood tests.

History and physical examination

The age of the patient may offer an important clue to the cause of rectal bleeding. For example, moderate to severe rectal bleeding in teenagers and young adults is more likely to come from a Meckel's diverticulum. Moderate or severe rectal bleeding in older individuals is more likely to be due to diverticulosis or angiodysplasias. Mild rectal bleeding in an adult with prior abdominal radiation treatment may be due to radiation proctitis.

The presence or absence of other symptoms also may provide important clues. Bleeding from diverticulosis, angiodysplasias, and Meckel's diverticula are usually not associated with abdominal or rectal pain. Rectal bleeding from ischemic colitis is often preceded by the sudden onset of lower abdominal, crampy pain. Fever, abdominal pain, and diarrhea often occur with colitis due to infection, ulcerative colitis, or Crohn's colitis. Mild bleeding accompanied with pain in the anal area during defecation (passing of stool) suggests bleeding from an anal fissure. A recent change in bowel habit such as increasing constipation or diarrhea suggests the possibility of cancer of the colon.

Inspection of the anus may disclose bleeding from a hemorrhoid or anal fissure. Unfortunately, most hemorrhoids and fissures are not actively bleeding at the time a patient arrives at the doctor's office. Thus, even if a doctor finds a hemorrhoid or anal fissure, he/she cannot be certain that they are the cause of the bleeding. Therefore, flexible sigmoidoscopy or colonoscopy will have to be done to exclude other potentially more serious causes of bleeding.

Medically Reviewed by a Doctor on 7/16/2014

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