Friday, April 18, 2014
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Rectal Bleeding

You have reported rectal bleeding along with symptoms of diarrhea, rectal urges, or both. These symptoms suggest inflammation of the colon or rectum. You need to be seen by your doctor. If you are having a lot of diarrhea, your doctor may be able to identify your diagnosis by testing a stool sample. However, most people who have rectal bleeding like yours will need a visual inspection of the inside of the rectum or colon. A lubricated hollow cylinder called an "anoscope" may be used by your doctor during your office visit. This hollow tube is approximately the diameter of a normal bowel movement. It can be pushed gently against your anus and inserted four or five inches into your rectum so that your doctor can view your rectum. In place of this, or in addition, a video inspection of your colon (a colonoscopy or flexible sigmoidoscopy test) may be scheduled.

The most common causes of inflammation in the colon or rectum include:

Inflammatory bowel disease

Inflammation in the rectum or colon can be the result of an autoimmune illness (an attack by your own immune system). If your symptoms have been persistent or recurrent, one of the autoimmune conditions known as "inflammatory bowel disease" may be the cause. Most inflammatory bowel disease is eventually identified as either "Crohn's disease" or "ulcerative colitis." Inflammatory bowel disease is more likely to be an explanation for your diarrhea if you are a young adult, although older adults can develop inflammatory bowel disease as well.

Antibiotic-associated diarrhea

An infection that causes diarrhea and bleeding can arise when harmful bacteria named clostridium difficile multiplies in the colon. Extra growth of "c. diff." bacteria often occurs after antibiotic treatment has killed some harmless bacteria in the colon, but has spared this potentially dangerous strain. If "c. diff." becomes the dominant bacteria in the colon, it can cause inflammation and symptoms.

Infectious diarrhea ("dysentery")

If your symptoms took several days to develop after exposure to food or water that may be contaminated, you may have a bacterial infection in your intestine. Diarrhea that contains blood or pus and arises from a bacterial infection is called "dysentery." Your stool sample can be tested for infections that are a cause of dysentery, including salmonella,shigella,campylobacter, and aggressive strains of e. coli.


Inflammation inside the rectum is known as "proctitis." Proctitis can be caused by contamination of the rectum with bacteria that is passed through sex, such as gonorrhea or a Chlamydia infection. It can also be caused by recent or previous radiation treatments. Radiation for prostate or pelvic cancer can cause rectal inflammation with as long as a 3-year delay after your last treatment.

Rectal cancer

Rectal cancer is a concern, especially if you are older than 50.

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Harvard Health Publications Source: from the Harvard Health Publications Family Health Guide, Copyright © 2007 by President and Fellows of Harvard College. All rights reserved.

Used with permission of StayWell.

Use of this content is subject to specified Terms and Conditions and a Medical Disclaimer.

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