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Last updated: June 2, 2023
Revisions: 24

Last updated: June 2, 2023
Revisions: 24

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Angiodysplasia is the most common vascular abnormality of the gastrointestinal tract. The condition is responsible for around 6% lower gastrointestinal bleeds and 8% of upper gastrointestinal bleeds.

Angiodysplasia describes the formation of arteriovenous malformations between previously healthy blood vessels. In the gastrointestinal tract, this most commonly occurs in the caecum and ascending colon.

The condition has a prevalence of 1-2% and is the second most common cause of rectal bleeding in those >60yrs. Of note, it is the most common cause for bleeding from the small bowel.

In this article, we shall look at the risk factors, clinical features and management of a patient with angiodysplasia.


Congenital causes of angiodysplasia include hereditary haemorrhagic telangectasia (Rendu-Osler-Weber syndrome), however the majority of cases are acquired.

Acquired angiodysplasia develops due to reduced submucosal venous drainage in the colon, from chronic and intermittent contraction of the colon, giving rise to dilated and tortuous veins. This results in the loss of pre-capillary sphincter competency and in turn causes the formation of small arterio-venous communications.

Both congenital and acquired cases will result in the formation of small tufts of dilated vessels (Fig. 1), which are prone to haemorrhage.

Figure 1 – Endoscopic view of gastric angiodysplasia


Clinical Features

The majority of patients with angiodysplasia will present with occult per rectum bleeding, being identified either through screening programmes (e.g. blood detected in stool sample) or as a new-onset anaemia.

Only 10-15% cases will present with an acute haemorrhage. This may manifest as haematochezia, melena, or haematemesis.

As the arteriovenous lesions can occur throughout the gastrointestinal tract, the degree of symptoms will depend upon the location and severity of the malformation.

Clinical examination is often unremarkable. In chronic cases, only clinical signs of anaemia may be evident.


Differential Diagnoses

The differentials for a patient presenting with acute gastrointestinal bleeding, depends whether haematochezia, melena, or haematemesis.



Patients with massive gastrointestinal bleeding secondary to suspected angiodysplasia require urgent fluid resuscitation with blood products and clinical stabilisation prior to any further investigations.

Ensure urgent blood tests are taken, including a full blood count, clotting profile, and group and save (with suitable blood products cross matched if required). Correct any underlying coagulopathy as required.

Following resuscitation, those with large bleeds will typically warrant a CT angiogram to help delineate the location of the bleed. If amenable, IR-guided embolization can be attempted to control the bleeding.

Further assessment

The definitive diagnosis, especially in stable cases, of angiodysplasia can be made via endoscopy. Any bleeding identified can then be stemmed via administration of therapeutic agents at endoscopy (see below).

  • Upper GI endoscopy (OGD) if the lesion is in a gastric or proximal duodenal location*
  • Colonoscopy if the lesion is in a colonic or terminal ileal location
  • Capsule endoscopy if the lesion is in a small bowel location (Fig. 2)

*Push enteroscopy can be used to assess distal duodenum and proximal jejunum in select cases

Fig 1 - Capsule endoscopy is the preferred imaging choice for small bowel angiodysplasia.

Figure 2 – Capsule endoscopy is the preferred imaging choice for small bowel angiodysplasia.



The majority of angiodysplasia cases can be managed endoscopically, typically through use of argon plasma coagulation (Fig. 3), whereby the bleeding vessel is subject to an electrical current and argon, acting as a safe and cost-effective treatment option.

Other endoscopic techniques include monopolar electrocautery, laser photoablation, sclerotherapy, and band ligation, yet our less commonly used.

For cases not accessible to endoscopy or are refractory to treatment, mesenteric angiography with super-selective catheterisation and embolization of the vessel can be trialled.

Figure 3 – Angiodysplasia being treated with argon plasma coagulation during endoscopy

Surgical Management

In a minority of cases, surgical intervention may be warranted. This is typically indicated in patients with acute large refractory bleeding or multiple angiodysplastic lesions, in which angiographic and endoscopic management have been unsuccessful.

The exact surgical resection performed depends on the location of the lesion, however the operation performed will require involve a gastric or bowel resection +/- primary anastomosis.



The complications of angiodysplasia are mainly related to the treatment, as re-bleeding post-therapy is relatively common.

Endoscopic techniques have a small risk of bowel perforation, whereas mesenteric angiography carries risks of haematoma formation, arterial dissection, and bowel ischaemia.

Key Points

  • Angiodysplasia is a relatively common cause of gastrointestinal bleeding
  • Most cases present as painless occult per rectum bleeding
  • Diagnosis is typically made through endoscopy
  • Most cases resolve with either endoscopic management or radiological approach