by EBSCO Medical Review Board
(Colonic Angiodysplasia, Arteriovenous Malformations [AVM] of the Colon)


Angiodysplasia of the colon is when blood vessels in the colon (large intestine) enlarge. They may become weak and result in bleeding in the digestive system.

Normal Anatomy of the Intestines
Normal Anatomy of the Large and Small Intestine
Copyright © 2002 Nucleus Communications, Inc. All rights reserved.


The exact cause is not known. It may be part of the aging process.

Risk Factors

This problem is more common in older adults. Other things that may raise the risk are:


Problems may be:

  • Dark, tarry stools
  • Bleeding from the rectum
  • Weakness
  • Fatigue
  • Problems breathing


The doctor will ask about your symptoms and health history. A physical exam will be done.

Blood and stool may be tested.

The internal structures of the body may need to be viewed. This can be done with:


Treatment may not be needed. The problem often goes away on its own. People who do need treatment may have:

  • A colonoscopy that uses heat to seal bleeding blood vessels
  • Angiography to clot the blood supply to the bleeding
  • Medicines called somatostatin analogs to prevent bleeding
  • Surgery to remove part of the colon


There are no current guidelines to prevent this problem.


American Geriatrics Society Foundation for Health in Aging 

National Institute of Diabetes and Digestive and Kidney Diseases 


Canadian Association of Gastroenterology 

Canadian Digestive Health Foundation 


Gastrointestinal angiodysplasia. EBSCO DynaMed website. Available at: Accessed October 22, 2020.

Jackson CS, Gerson LB. Management of gastrointestinal angiodysplastic lesions (GIADs): a systematic review and meta-analysis. Am J Gastroenterol. 2014 Apr;109(4):474-483.

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