Angiodysplasia of the colon is swollen, fragile blood vessels in the colon that occasionally result in blood loss from the gastrointestinal (GI) tract.
Vascular ectasia of the colon; Colonic arteriovenous malformation
Causes, incidence, and risk factors
Angiodysplasia of the colon is mostly related to the aging and degeneration of the blood vessels. It usually occurs in older adults. It is almost always seen on the right side of the colon.
There are several theories about the cause. The most likely cause is that normal spasms of the colon lead to enlargement of blood vessels in the area. This swelling becomes so severe that a small direct passageway develops between a very small artery and vein. This is called an arteriovenous fistula. It is in this area of the colon wall that the patient is at risk for bleeding.
Angiodysplasia of the colon is very rarely related to other diseases of the blood vessels, including Osler-Weber-Rendu syndrome. It is not related to cancer, and is different than diverticulosis, a more common cause of intestinal bleeding in older adults.
The symptoms vary. Often, in elderly patients, the symptoms are weakness, fatigue, and shortness of breath due to anemia. 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.
There is no pain associated with angiodysplasia.
Signs and tests
Tests that may be done to diagnose this condition include:
Angiography (only useful if there is active bleeding into the colon)
Complete blood count (CBC) to check for anemia
Stool test for occult (hidden) blood (a positive test result suggests bleeding from the colon)
It is important to determine what is causing the bleeding in the colon and how fast blood is being lost. You may need to be admitted to a hospital. Fluids may be given through a vein, and blood products may be required.
Other treatment may be needed once the source of bleeding is found. Most patients stop bleeding on their own without any treatment.
If treatment is needed, it may involve:
Angiography to help block the blood vessel that is bleeding or to deliver medicine to help cause the blood vessels to tighten to stop the bleeding
Burning (cauterizing) the site of the bleed with heat or a laser using a colonoscope
In some instances, surgery is the only option. Removal of the entire right side of the colon (right hemicolectomy) is the treatment of choice for someone with this condition who continues to bleed at a dangerously quick rate, despite several treatments by angiography and colonoscopy.
Medications (thalidomide and estrogens) may be used to reduce bleeding and the number of angiodysplasias in certain patients.
Patients who have bleeding related to this condition despite having had colonoscopy, angiography, or surgery are likely to have more bleeding in the future.
The outlook remains good if the bleeding is controlled.
Call your health provider if rectal bleeding occurs.
There is no known prevention.
Hauser S. Vascular diseases of the gastrointestinal tract. In: Goldman L, Ausiello D. Cecil Textbook of Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 146.
Brandt LJ, Landis CS. Vascular lesions of the gastrointestinal tract. In: Feldman M, Friedman LS, Brandt LJ, eds. Sleisenger and Fordtran's Gastrointestinal and Liver Disease. 9th ed. Philadelphia, Pa: Saunders Elsevier; 2010:chap 36.
David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine; George F. Longstreth, MD, Department of Gastroenterology, Kaiser Permanente Medical Care Program, San Diego, California. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.