Mesenteric Ischaemia/Infarction

Question 1

Aetiology of Mesenteric Ischaemia.

Answer 1

A lack of blood flow through the mesenteric vessels supplying the intestines.

Question 2

Embryological Classification of the Gut (3).

Answer 2

1. FOREGUT - Stomach, Biliary System, Liver, Pancreas, Spleen and Part of the Duodenum.
2. MIDGUT - Distal Duodenum to the First Half of the Transverse Colon.
3. HINDGUT - Second Half of the Transverse Colon to the Rectum.

Question 3

Arterial Supply of the Gut (3).

Answer 3

1. FOREGUT - Coeliac Artery.
2. MIDGUT - Superior Mesenteric Artery.
3. HINDGUT - Inferior Mesenteric Artery.
   * all are branches of the abdominal aorta.

Question 4

Types of Lower GI Ischaemia (3).

Answer 4

1. Acute Mesenteric Ischaemia.
2. Chronic Mesenteric Ischaemia.
3. Ischaemic Colitis.

Question 5

What is Acute Mesenteric Ischaemia?

Answer 5

Severe life-threatening general surgical emergency - sudden-onset intestinal hypo perfusion.

Question 6

Aetiology of Acute Mesenteric Ischaemia.

Answer 6

Rapid blockage in blood flow through the Superior Mesenteric Artery - usually a thrombus (or embolus).

Question 7

Risk Factors of Acute Mesenteric Ischaemia (4).

Answer 7

1. AF - Thrombus forms in Left Atrium and mobilises down aorta to SMA.
2. Emboli - Infective Endocarditis, AAA.
3. Atherosclerosis.
4. Coagulopathy.

Question 8

Clinical Presentation of Acute Mesenteric Ischaemia (3).

Answer 8

1. Acute Non-Specific Abdominal Pain that is DISPROPORTIONATE to Examination Findings.
2. Shock, Peritonitis and Sepsi.
3. PR Bleeding - Advanced Ischaemia.

Question 9

Investigations of Acute Mesenteric Ischaemia (2).

Answer 9

1. Contrast CT - Assess Bowel and Blood Supply.

2. Bloods - Metabolic Acidosis and Raised Lactate.

Question 10

Management of Acute Mesenteric Ischaemia (2).

Answer 10

IMMEDIATE LAPAROTOMY :

1. Remove Necrotic Bowel.
2. Remove/Bypass Thrombus in Blood Vessel (Open Surgery/Endovascular Surgery).

Question 11

Prognosis of Acute Mesenteric Ischaemia.

Answer 11

High mortality (over 50%) - ischaemia will result in necrosis and perforation.

Question 12

Aetiology of Chronic Mesenteric Ischaemia.

Answer 12

Narrowing of mesenteric blood vessels by atherosclerosis; intestinal angina.

Question 13

Clinical Presentation of Chronic Mesenteric Ischaemia (3).

Answer 13

1. Intermittent central colicky (starting around 30 minutes after eating, lasting 1-2 hours) abdominal pain.
2. Weight Loss (food avoidance - pain).
3. Abdominal Bruit (Auscultation).

Question 14

Risk Factors of Chronic Mesenteric Ischaemia.

Answer 14

Same as any other cardiovascular disease.

Question 15

Investigation of Chronic Mesenteric Ischaemia.

Answer 15

CT Angiography - relatively rare clinical diagnosis.

Question 16

Management of Chronic Mesenteric Ischaemia (3).

Answer 16

1. Reduce Modifiable Risk Factors.
2. Secondary Prevention (Statins and Antiplatelets).
3. Revascularisation (improve blood flow to the intestines).

Question 17

Revascularisation in Chronic Mesenteric Ischaemia (2).

Answer 17

1. Endovascular Surgery 1st Line - Percutaneous Mesenteric Artery Stenting.
2. Open Surgery - Endarterectomy, Re-implantation or Bypass Grafting.

Question 18

What is Ischaemic Colitis?

Answer 18

An acute but transient compromise in the blood flow to the large bowel, leading to inflammation, ulceration and haemorrhage.

Question 19

Risk Factors of Ischaemic Colitis.

Answer 19

Cardiovascular Risk Factors and Cocaine Use (Younger Patients).

Question 20

Where is Ischaemic Colitis more likely to occur?

Answer 20

Watershed Areas e.g. Splenic Flexure - borders of the territory supplied by the SMA and IMA.

Question 21

Investigation of Ischaemic Colitis.

Answer 21

AXR : ‘Thumbprinting’ - Mucosal Oedema/haemorrhage.

Question 22

Management of Ischaemic Colitis (2).

Answer 22

1. Conservative.

2. Surgery - minority cases : peritonitis, perforation, ongoing haemorrhage.