Ischaemia to the lower GI tract

Question 1

Can be useful to separate cases into 3 main conditions:

Answer 1

Acute mesenteric ischaemia
Chronic mesenteric ischaemia
Ischaemic colitis

Question 2

Acute mesenteric ischaemia

Answer 2

Acute mesenteric ischaemia is typically caused by an embolism resulting in occlusion of an artery which supplies the small bowel, for example the superior mesenteric artery. Classically patients have a history of atrial fibrillation.

The abdominal pain is typically severe, of sudden onset and out-of-keeping with physical exam findings.

Management

• urgent surgery is usually required
• poor prognosis, especially if surgery delayed

Question 3

Chronic mesenteric ischaemia

Answer 3

Chronic mesenteric ischaemia is a relatively rare clinical diagnosis due to it’s non-specific features and may be thought of as ‘intestinal angina’. Colickly, intermittent abdominal pain occurs.

Question 4

Ischaemic colitis

Answer 4

Ischaemic colitis describes an acute but transient compromise in the blood flow to the large bowel. This may lead to inflammation, ulceration and haemorrhage. It is more likely to occur in ‘watershed’ areas such as thesplenic flexurethat are located at the borders of the territory supplied by the superior and inferior mesenteric arteries.

Investigations

• ‘thumbprinting’ may be seen on abdominal x-ray due to mucosal oedema/haemorrhage

Management

• usually supportive
• surgery may be required in a minority of cases if conservative measures fail. Indications would include generalised peritonitis, perforation or ongoing haemorrhage

Question 5

Common predisposing factors in bowel ischaemia

Answer 5

• increasing age
• atrial fibrillation - particularly for mesenteric ischaemia
• other causes of emboli: endocarditis, malignancy
• cardiovascular disease risk factors: smoking, hypertension, diabetes
• cocaine: ischaemic colitis is sometimes seen in young patients following cocaine use

Question 6

Common presenting features in bowel ischaemia (generally)

Answer 6

• abdominal pain - in acute mesenteric ischaemia this is often of sudden onset, severe and out-of-keeping with physical exam findings
• rectal bleeding
• diarrhoea
• fever
• bloods typically show an elevated white blood cell count associated with alactic acidosis

Question 7

Mesenteric Ischaemia usually presents with a classic triad of?

Answer 7

CVD
High lactate
Soft but tender abdomen

Question 8

Intestinal angina (or chronic mesenteric ischaemia) is classically characterised by a triad of?

Answer 8

severe, colicky post-prandial abdominal pain, weight loss, and an abdominal bruit - by far the most common cause is atherosclerotic disease in arteries supplying the GI tract