Angiodysplasia

What angiodysplasia is

Angiodysplasias are flat, cherry-red patches, usually 2 to 10 mm across, made of thin-walled, widened capillaries and veins in the inner layers of the gut wall. They are not tumors and do not become cancer. Because their walls are thin and close to the surface, they can ooze blood into the gut.

They are among the most common vascular lesions of the digestive tract and are found in a small percentage of people having colonoscopy, many of whom never bleed. In people with unexplained bleeding from the small bowel, angiodysplasia is the most common cause in those over 40.

Causes and risk factors

The exact cause is uncertain. The leading theory is that, with age, repeated contraction of the bowel wall partially blocks the veins draining the lining, causing them to stretch and eventually form small connections between arteries and veins. This explains why lesions are more common with age and in the wide right colon, where wall tension is highest.

Conditions linked with angiodysplasia or its bleeding:

• Age over 60
• Chronic kidney disease, especially on dialysis
• Aortic stenosis: the narrowed valve breaks down a clotting protein (von Willebrand factor), increasing bleeding. This combination is called Heyde syndrome
• Von Willebrand disease and other bleeding disorders
• Left ventricular assist devices (LVADs) for heart failure
• Blood thinners and antiplatelet medicines, which make lesions more likely to bleed
• Liver cirrhosis

Hereditary hemorrhagic telangiectasia is a separate, inherited condition that causes similar lesions throughout the gut, along with nosebleeds and skin spots.

Symptoms

Many people have no symptoms. When angiodysplasia bleeds, it usually causes:

• Slow, hidden (occult) bleeding: a positive stool blood test and iron deficiency anemia, causing tiredness, breathlessness, pale skin and dizziness
• Intermittent visible bleeding: black, tarry stools (melena) from the small bowel or stomach, or maroon or red blood from the colon
• Occasionally, heavy bleeding with fainting and a drop in blood pressure

Bleeding is painless. Abdominal pain suggests a different cause.

Diagnosis

Angiodysplasia is usually found while investigating anemia or bleeding:

1. Blood tests: hemoglobin, iron studies, kidney function and clotting tests.
2. Upper endoscopy and colonoscopy: the first tests, which also rule out ulcers, polyps and cancer.
3. Capsule endoscopy: a swallowed pill camera photographs the small intestine. It is the main test when upper endoscopy and colonoscopy are normal.
4. Device-assisted enteroscopy (single- or double-balloon): reaches deep into the small bowel to both confirm and treat lesions.
5. CT angiography or a tagged red cell scan: for active bleeding, to locate the source.
6. Mesenteric angiography: can locate and block a bleeding vessel during heavy bleeding.

An echocardiogram may be advised if a heart murmur suggests aortic stenosis.

Treatment

Lesions that are not bleeding usually need no treatment. For bleeding lesions:

Endoscopic therapy

Argon plasma coagulation (APC) uses ionized gas to deliver heat that seals the vessels. It is the most common treatment and is done during endoscopy, colonoscopy or enteroscopy. Clips, bipolar coagulation and injections are alternatives. Lesions often recur, and repeat sessions may be needed.

Iron replacement and transfusion

Oral or intravenous iron corrects anemia. IV iron is often preferred when bleeding is ongoing or tablets are not absorbed or tolerated. Blood transfusion is used for severe anemia or heavy bleeding.

Medicines for recurrent bleeding

When bleeding keeps recurring despite endoscopic treatment, specialists may use:

• Octreotide (a somatostatin analog), given by injection
• Thalidomide, in selected cases, with strict safety precautions

Hormone therapy is no longer recommended because trials showed no benefit.

Reviewing other medicines

Blood thinners and antiplatelet drugs may be adjusted where safely possible, balancing bleeding risk against clot risk.

Treating related conditions

In Heyde syndrome, aortic valve replacement often stops the bleeding by restoring normal von Willebrand factor.

Surgery and embolization

Surgical removal of a section of bowel, such as a right hemicolectomy, or embolization during angiography is reserved for heavy bleeding that cannot be controlled otherwise.

Outlook

Angiodysplasia is not dangerous in itself, and many people with it never bleed. Among those who do, rebleeding is common, especially with small bowel lesions, blood thinners or kidney disease. Most can be managed effectively with periodic endoscopic treatment and iron, keeping anemia under control.

Frequently asked questions

What is angiodysplasia?

Angiodysplasia is a small collection of fragile, enlarged blood vessels in the lining of the digestive tract, usually in the colon or small intestine. It can bleed slowly, causing iron deficiency anemia, or occasionally cause visible bleeding. It is most common in older adults.

What causes angiodysplasia of the colon?

It is thought to develop with age as the colon wall repeatedly contracts and partly blocks the small veins in the lining, which gradually stretch and form abnormal vessels. Kidney disease, aortic stenosis and bleeding disorders increase the chance of bleeding.

Is angiodysplasia cancer?

No. Angiodysplasia is a benign vascular abnormality and does not turn into cancer. Because bleeding and anemia can also come from bowel cancer, doctors usually perform a colonoscopy to rule out cancer before attributing bleeding to angiodysplasia.

How is angiodysplasia treated?

Bleeding lesions are usually sealed during endoscopy with argon plasma coagulation. Iron replacement corrects anemia. For repeated bleeding, medicines such as octreotide may be used, and surgery is rarely needed.

Can angiodysplasia come back after treatment?

Yes. Treated lesions can re-bleed and new lesions can form, especially in the small bowel and in people with kidney disease or taking blood thinners. Repeat endoscopic treatment and monitoring of blood counts are often needed.