ischemia

Question 1

define ischemia to lower gi tract and how it is classified

Answer 1

schaemia to the lower gastrointestinal tract can result in a variety of clinical conditions. Whilst there is no standard classification it can be useful to separate cases into 3 main conditions

1. acute mesenteric ischaemia
2. chronic mesenteric ischaemia
3. ischaemic colitis

Question 2

what are the diff types of bowel ischemia

Answer 2

Question 3

Common predisposing factors

Answer 3

• 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 4

Common features

Answer 4

• 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 a lactic acidosis

Question 5

Diagnosis

Answer 5

CT is the investigation of choice

Question 6

Acute mesenteric ischaemia

Answer 6

• 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 7

Chronic mesenteric ischaemia

Answer 7

• 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 8

Ischaemiac colitis

Answer 8

• 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 the splenic flexure that 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