Mesenteric Ischaemia or Infarction Flashcards
Ischaemia to the lower gastrointestinal tract can result in a variety of clinical conditions.
What are the common predisposing factors in bowel ischaemia?
- 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
What are common features of bowel ischaemia?
- abdominal pain - in acute mesenteric ischaemia this is often sudden + severe and out-of-keeping with physical exam findings
- rectal bleeding
- diarrhoea
- fever
What investigations are done for bowel ischaemia?
- WBC → elevated
- Lactic acidosis
- CT first-line
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?
- urgent surgery is usually required
- poor prognosis, esp if surgery delayed
What are important causes of bowel infarction?
- 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
Where might thromboemboli originate from?
- 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
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?
- acute colicky abdominal pain
- rectal bleeding
- shock (due to associated blood loss)
- maybe abdo pain
- signs of peritonism
What is the management of bowel infarction?
- 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
What are the differences between mesenteric ischaemia and ischaemic colitis?