Gastrointestinal Angiodysplasia

Angiodysplasias are vascular lesions formed when the small blood vessels in the wall of the digestive tract dilate and become fragile. Their most important feature is that, although they sometimes cause no symptoms at all, they can lead to occult or visible gastrointestinal bleeding.

They are commonest in the colon, and the right colon and caecum are frequent sites in particular. They can, however, also be found in the stomach and the small intestine.

Why do they form?

The exact mechanism is not always known. Dilatation and structural change in the small vessels of the bowel wall over time, with age, is accepted as one of the important mechanisms.

Angiodysplasias are therefore commoner at older ages in particular.

They can occur more often alongside certain cardiac, renal and haematological conditions.

What are the symptoms?

Many people with an angiodysplasia have no complaint at all, and it can be found incidentally at a colonoscopy or endoscopy carried out for another reason.

When bleeding does occur it can appear in different ways:

• Red or maroon blood in the stool
• Black, tarry stools
• Chronic blood loss invisible to the eye
• Iron deficiency
• Iron deficiency anaemia
• Tiredness and fatigue
• Breathlessness or palpitations

One of the important features of the bleeding is that it is intermittent. It can stop and then start again later.

Is an angiodysplasia cancer?

No. An angiodysplasia is not cancer and is not a precancerous lesion. It is an abnormality of vascular structure.

But where there is anaemia or gastrointestinal bleeding, particularly in an older patient, other possible causes need to be assessed before attributing the bleeding directly to an angiodysplasia.

Can it cause iron deficiency anaemia?

Yes. This is one of the important clinical features of angiodysplasia.

Blood loss from the lesion can be small in amount but repeated. Iron deficiency anaemia can develop over time even though the patient never sees any blood in the stool.

When the gastrointestinal tract is investigated in unexplained iron deficiency anaemia, angiodysplasias are therefore among the possible causes.

How is the diagnosis made?

Different methods can be used according to where the lesion is.

Colonoscopy

One of the most important methods for diagnosing angiodysplasias in the colon. The lesions can generally be seen as flat, reddish, dilated networks of vessels in the mucosa.

Gastroscopy

Allows vascular lesions in the stomach and duodenum to be assessed.

Capsule endoscopy

Can be particularly useful for investigating angiodysplasias in the small intestine, in suitable patients where the source of bleeding cannot be found by gastroscopy and colonoscopy.

Enteroscopy

Can allow lesions found in the small intestine to be seen directly and, in some situations, treated in the same session.

Where there is active and obvious bleeding, methods such as CT angiography or conventional angiography may also be needed.

Does every angiodysplasia have to be treated?

No.

Angiodysplasias found incidentally at an endoscopy carried out for another reason, and which are not causing bleeding, do not always have to be treated.

Treatment comes into question particularly in patients with active bleeding, recurrent bleeding or iron deficiency anaemia.

Can it be treated endoscopically?

Yes. Endoscopic treatment can be applied to suitable lesions thought to be causing bleeding.

One of the most frequently used methods is argon plasma coagulation (APC). Controlled energy is applied with the aim of coagulating the abnormal vessels and stopping the bleeding.

Other endoscopic methods of bleeding control can also be used according to the features of the lesion.

Does it bleed again after treatment?

Yes. One of the important features of angiodysplasias is that the bleeding can recur.

Even where one lesion has been treated successfully, angiodysplasias may be present in other areas or new lesions may appear over time. Long-term follow-up is therefore needed in some patients.

Do blood-thinning medicines matter?

Blood thinners and other medicines that affect clotting can make bleeding from an existing vascular lesion more likely, or more severe.

But these medicines are mostly taken for important cardiovascular conditions. A patient should not stop their medicine on their own decision. The risks of bleeding and of clotting have to be weighed together.

Is there a link with heart disease?

There is a known relationship between severe aortic stenosis in particular and bleeding from gastrointestinal angiodysplasias. This association is in some circumstances called Heyde’s syndrome.

Knowing what other conditions are present therefore matters in patients with recurrent angiodysplasia bleeding, particularly at older ages.

In brief

Angiodysplasia = fragile, dilated small vascular structures in the wall of the digestive tract.

Its most important consequences can run:

Angiodysplasia → intermittent bleeding → chronic blood loss → iron deficiency anaemia

It is not cancer. Not every angiodysplasia that causes no symptoms needs treatment. A substantial proportion of lesions that do bleed can be treated endoscopically.

Important: obvious blood in the stool, black tarry stools, dizziness, fainting, palpitations or marked weakness can be signs of significant gastrointestinal bleeding and need medical assessment without delay.