Angiodysplasia of the colon is a condition of stretched and fragile blood vessels in the colon that results in occasional loss of blood from the gastrointestinal (GI) tract. The condition is mostly related to the aging and degeneration of the blood vessels, and occurs in older adults.

Angiodysplasia of the colon is not related to cancer. It is very rarely related to other diseases of the blood vessels, including Osler-Weber-Rendu syndrome. It is different than diverticulosis, another very common cause of bleeding in older adults.

There are several theories about the cause of angiodysplasia of the colon. The most likely is that normal contractions of the colon result in dilation (stretching) of colonic veins, venules, and capillaries. The dilation becomes so severe that a small direct passageway develops between the artery and vein (arteriovenous fistula). It is in this area of the colon wall that the patient is at risk for bleeding.

Angiodysplasia of the colon has been seen in about 3% of "nonbleeding persons" and in about 5% of patients evaluated for blood in the stool, anemia, or hemorrhage. Men and women are equally at risk for developing angiodysplasia of the colon. Most patients are older than 50 years.

The symptoms vary. Often, in elderly patients, the symptoms are anemia, weakness, fatigue, and shortness of breath. There may not be any signs of bleeding directly from the colon. Others may have occasional mild or severe bleeding episodes with bright red blood coming from the rectum.

Some patients may have dark or black, tarry stools. There is no pain associated with angiodysplasia.

Tests that may be done to diagnose this condition include:

• Angiography (only useful if there is active bleeding into the colon)
• CBC
• Colonoscopy
• Stool guaiac (a positive test result suggests bleeding from the colon)

When a patient is bleeding from the colon, it is important to determine the source of the bleeding and the rate of blood loss. The patient's condition must be evaluated continuously and may require admission to an intensive care unit (ICU). Administration of IV fluids, and blood products may be required.

Once the source of the bleeding is found (usually by angiography or colonoscopy), treatment can begin. As many as 90% of vascular ectasias stop bleeding on their own without any treatment.

When intervention is needed, however, the colonoscope can cauterize (burn) the site of hemorrhage (bleeding). This procedure can be done electrically, with heat or with a laser. Argon plasma coagulation (APC) is a relatively new method of electrocoagulation that uses electrical energy to stop bleeding. The electricity does not come in contact with the tissue. Complications of this procedure include puncture of the colon, as well as possible treatment failure.

Actively bleeding vascular ectasia can also be treated by angiography by clotting the blood supply to the bleeding area of the colon. The use of chemicals that cause the blood vessels to constrict can also be administered, whether by angiography or colonoscope.

In some instances, surgery is the only option. A right hemicolectomy, or removal of the entire right side of the colon, may be required. This remains the treatment of choice for a patient whose ectasia continues to bleed at a dangerously quick rate, despite several therapeutic interventions by angiography and colonoscopy.

As mentioned above, bleeding in more than 90% of instances stops on its own. However, patients who have bleeding angiodysplasia despite having had colonoscopy, angiography, or surgery, are likely to have more bleeding in the future.

The goal of repeat endoscopic therapy is to reduce, if not totally eliminate, the number of bleeds, hospitalizations, and transfusions. Surgery may be a cure in some cases. Prognosis remains good if the bleeding is controlled.

• Severe loss of blood from the gastrointestinal tract
• Anemia
• Death from excessive blood loss

Call your health provider if rectal bleeding or black stools occur.

There is no known prevention.