November 26, 2015
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Blood in the Stool (Rectal Bleeding) (cont.)

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Meckel's diverticulum

A Meckel's diverticulum is an out-pouching (sack) that protrudes from the small intestine near the junction of the small intestine and the colon. It is present from birth and occurs in a small percentage of the population. Some Meckel's diverticula can secrete acid, like the stomach, and the acid can cause ulcerations in the inner lining of the diverticulum or the tissues of the small intestine adjacent to the diverticulum. These ulcers can bleed. Bleeding from a Meckel's diverticulum is the most common cause of gastrointestinal bleeding in children and young adults. Bleeding from a Meckel's diverticulum is painless but can be brisk and can cause bright red, dark red, or maroon stools.


Colon polyps found during colonoscopy usually are removed, a process called polypectomy. Bleeding can occur at the site of the polypectomy days to weeks after the polyp is removed. Such bleeding is called delayed post-polypectomy bleeding. Smaller polyps (2-3 mm in size) can be removed with biopsy forceps. The amount of blood loss from the use of a forceps usually is minute, and there will be no delayed bleeding. However, larger polyps (larger than 5-10 mm) usually are removed with an electro-surgical snare. These snares are connected to a machine that generates an electrical current. The polyp is looped within a snare, and electrical current is passed through the snare. The electrical current cuts off the polyp and cauterizes ("heat seals") the tissue at the base of the polyps. Cauterization prevents bleeding during polypectomy; however, the site of cauterization heals with the formation of an ulcer. Rarely, these ulcers can bleed several days to up to 2-3 weeks after polypectomy. Post-polypectomy bleeding can at times be brisk and severe, and can be bright red, dark red, maroon colored, or black.

Rare causes of rectal bleeding

Rarely, rapid and severe bleeding from the upper gastrointestinal tract (for example, ulcers of the stomach or duodenum) can cause bright red rectal bleeding. Other rare causes include leaking of larger amounts of blood into the gastrointestinal tract when a blood vessel ruptures. This may occur when an ulcer of the gastrointestinal tract erodes into a nearby artery or when an arterial graft, for example, an aortic graft used to repair an aortic aneurysm, erodes into the gastrointestinal tract. Even more rare is bleeding from a rectal ulcer, or tumors of the small intestine.

What kind of doctor treats rectal bleeding?

Rectal bleeding usually is managed by a gastroenterologist a colon and rectal surgeon, or a proctologist.

When should I call a doctor for blood in the stool (rectal bleeding)?

Any blood in the stool is not normal and should be reported to a health-care professional. However, there are certain circumstances that might be considered an emergency and medical care should be accessed immediately. These situations include:

  • Black, tarry stools that may be due to bleeding from the esophagus, stomach or duodenum (upper gastrointestinal [GI] tract). This is especially a potentially serious concern in patients with liver disease and/or portal hypertension who have esophageal varices. This is a potential life threatening situation.
  • Maroon colored stool may be caused by an upper GI bleed or a bleeding source in the small intestine.
  • Lightheadedness, weakness, fainting (syncope), chest pain or shortness of breath may be symptoms of significant blood loss.
  • Bleeding that is associated with fever and abdominal pain.
Medically Reviewed by a Doctor on 10/29/2015


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