Mesenteric Ischaemia or Infarction

Question 1

Ischaemia to the lower gastrointestinal tract can result in a variety of clinical conditions.

What are the common predisposing factors in bowel ischaemia?

Answer 1

• increasing age
• AF → particularly for mesenteric ischaemia
• other causes of emboli: endocarditis, malignancy
• cardiovascular disease risk factors → smoking, HTN, DM
• cocaine → ischaemic colitis is sometimes seen in young pts following cocaine use

Question 2

What are common features of bowel ischaemia?

Answer 2

• abdominal pain - in acute mesenteric ischaemia this is often sudden + severe and out-of-keeping with physical exam findings
• rectal bleeding
• diarrhoea
• fever

Question 3

What investigations are done for bowel ischaemia?

Answer 3

• WBC → elevated
• Lactic acidosis
• CT first-line

Question 4

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.

What is the management of acute mesenteric ischaemia?

Answer 4

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

Question 5

What are important causes of bowel infarction?

Answer 5

• strangulating bowel obstruction
• occlusion of mesenteric artery by an embolus
• occlusion of mesenteric artery by a thrombus
• occlusion of mesenteric artery by an aortic dissection extending into mesenteric artery
• compression of veins in bowel wall (due to bowel obstruction)
• occlusion of a mesenteric vein by thrombus
• vasculitis
• non-occlusive infarction eg. shock

Question 6

Where might thromboemboli originate from?

Answer 6

• left atrium in a pt w/ atrial fib
• mural thrombus secondary to MI
• a vegetation on a heart valve in a pt w/ infective endocarditis
• an atheromatous plaque in aorta which ruptures

Question 7

Bowel infarction is difficult to recognise clinically and so clinicians must have a high index of suspicion and actively consider the diagnosis. What are the classical clinical symptoms?

Answer 7

• acute colicky abdominal pain
• rectal bleeding
• shock (due to associated blood loss)
• maybe abdo pain
• signs of peritonism

Question 8

What is the management of bowel infarction?

Answer 8

• resusciated w/ IV fluids
• given broad spectrum antibiotics
• urgent laparotomy where any dead bowel resected
• revascularisation by embolectomy or bypass may improve doubtfully viable bowel and allow primary anastomosis

Question 9

What are the differences between mesenteric ischaemia and ischaemic colitis?

Answer 9