General surgery - mesenteric ischaemia

Question 1

Blood supply to the abdominal organs

Answer 1

Three main branches from the abdominal aorta

• Coeliac artery - supplies the foregut - the stomach, part of the duodenum, biliary system, liver, pancreas and spleen
• Superior mesenteric artery - supplies the distal duodenum, and 1/2 half transverse colon
• Inferior mesenteric artery - supplies the second half of the transverse colon to the rectum

Question 2

What is mesenteric ischaemia?

Answer 2

Lack of blood flow through mesenteric arteries supplying the intestines resulting in ischaemia

Can be acute or chronic

Question 3

Chronic mesenteric ischaemia presentation

Answer 3

Also known as intestinal angina - due to narrowed vessels due to atherosclerosis

Classical triad of:

• Central colicky abdominal pain after eating
• Weight loss (due to food avoidance - as this causes pain)
• Abdominal bruit on auscultation

Question 4

Risk factors for chronic mesenteric ischaemia

Answer 4

Increased age
Family history 
Smoking
Diabetes
Hypertension 
Raised cholesterol

Question 5

Diagnosis of chronic mesenteric ischaemia is with…

Answer 5

CT angiography

Question 6

Management of chronic mesenteric ischaemia

Answer 6

Reduce modifiable RFs (e.g. smoking cessation, BP control)

Secondary prevention - statins, anti-platelets medications

Revascularisation

• Endovascular stenting (first line)
• Open surgery e.g. endarterectomy, re-implantation or bypass

Question 7

Acute mesenteric ischaemia pathophysiology and RFs

Answer 7

Rapid blockage to blood flow in typically the SMA

Usually the blockage is caused by a thrombus - may be a thrombus or an embolus

A key RF is AF

Question 8

Presentation of acute mesenteric ischaemia

Answer 8

Acute non-specific abdominal pain

Pain is disproportionate to examination findings

Patients can go on to develop shock, peritonitis and sepsis.

Question 9

Investigations in acute mesenteric ischaemia to aid diagnosis

Answer 9

Contrast CT - diagnostic test of choice - to assess both the bowel and the blood supply.

ABG:
- Metabolic acidosis and raised lactate due to ischaemia

Question 10

Treatment of acute mesenteric ischaemia and prognosis

Answer 10

Patients will require surgery to remove necrotic bowel and remove/bypass the thrombus

High mortality (>50%)

Question 11

Complications of mesenteric ischaemia

Answer 11

High mortality rates
Perforation of the bowel
Necrosis of the bowel