Angiodysplasia Flashcards
What is the most common vascular abnormality of the GI tract?
Angiodysplasia
Responsible for approx 6% of lower GI bleeds and 8% of upper GI bleeds.
What causes angiodysplasia?
Formation of arterivenous malformations between previously healthy blood vessels
Where does angiodysplasia most commonly occur?
In the caecum and ascending colon
Epidemiology
1-2% prevalence
Second most common cause of rectal bleed in those >60y
Most common cause for bleeding from small bowel
Pathophysilogy of acquired angiodysplasia
Reduced submucosal venous drainage in the colon due to chronic and intermittent contraction of the colon.
This gives rise to dilated and turtuous veins.
This further causes loss of pre-capillary sphincter competency and in turn causes the formation of small arteriovenous communications.
This is characterised by a small tuft of dilated vessels.
Pathophysiology of congenital angiodysplasia.
Hereditary haemorrhagic telangiectasia
Rendu-Osler-Weber syndrome
Heyde’s syndrome
What is Heyde’s syndrome
Aortic stenosis + angiodysplasia
Leads to GI bleed
Clinical features
Rectal bleeding and anaemia
Can be asymptomatic and only diagnosed incidentally on colonscopy (10%)
Painless occult PR bleed (most common presentation)
Acute haemorrhage (10-15% of cases)
What does the clinical presentation depend on?
On the location and severity of the arteriovenous malformation.
Upper GI lesions can cause haematemesis or melaena
Lower GI lesions (more common) are more likely to present as haematochezia
Dx
Oesophageal varices
GI malignancies
Diverticular disease
Coagulopathies
Examination findings
Usually minimal or completely normal
In Heyde’s syndrome there might be aortic stenosis
Laboratory investigations
Blood tests with FBC, U&Es, LFTs and clotting + haematinics
G&S or crossmatch might be warranted if there is a need for transfusion.
Imaging of angiodysplasia.
OGD to exclude malignancy
Colonoscopy if more leading towards a distal AV lesion.
Small bowel AV lesions might be hard to identify.
How is this done?
By wireless capsule endoscopy
If there is an overt angiodysplastic bleed, what investigation might be done?
Mesenteric angiography to confirm the location of a lesion
This is in order to plan for intervention as necessary.
What can angiography involve?
Radionuclide scanning
CT scanning
MRI scanning
This is to image the GI tract vascular supply after injection of a radio-opaque contrast into the vessels
How can patients admitted with angiodysplasia be treated?
Conservatively especially if there is only minimal limited bleeding in a haemodynamically stabe patient.
Bed-rest and IV fluid support along with potential tranexamic acid.
10% of patients with angiodysplasia will present with a major GI bleed and need to be managed according to that protocol.
Indications for definitive therapy.
Persistent or severe cases when bleeding sites are identified.
Two main methods of definitive treatment
Endoscopy therapies
Radiographic therapies (mesenteric angiography)
What is usually the first line of management?
Endoscopy therapy with argon plasma coagulation
Explain argon plasma coagulation
Electrical current and argon are subjected to the bleeding vessel.
This is a safe, cost-effective and usually successful treatment option.
Give exampes of other endoscopic techniques
Monopolar electrocautery
Laser photoablation
Sclerotherapy
Band ligation
When is mesenteric angiography done?
Used for small bowel lesions that cannot be treated endoscopically.
Explain mesenteric angiography
Involves super-selective catheterisation and embolisation of the vessel that has been demonstrated to the bleeding.
This is by extravasation of contrast dye into the bowel lumen from the identified angiodysplastic lesion.
When else might mesenteric angiography be indicated?
GI bleed from any other location where endoscopic therapy failed
When endoscopy is not a suitable option like people who are unfit for it.
Explain surgical intervention.
Where resection and anastomosis of the affected segment of bowel is required to limit bleeding
Bowel resection in patients with angiodysplasia is associated with a relatively high mortality.
Indications of surgical management
Continuation of severe bleeding despite angiographic and endoscopic management
Severe acute life-threatening GI bleed
Multiple angiodysplastic lesions that cannot be treated medically
Complications of angiodysplasia
Mainly related to treatment
Re-bleeding post-therapy is quite common
Endoscopic techniques have a small risk of bowel perforatio
Mesenteric angiography carries risks of haematoma formation, arterial dissection, thrombosis and bowel ischaemia.
