GI topics

Question 1

What pathophysiological processes lead to gut ischaemia?

Answer 1

1. Arterial embolism
2. Arterial thrombosis
3. Non-occlusive mesenteric ischaemia
4. Mesenteric venous thrombosis

Question 2

Describe arterial embolism in gut ischaemia

Answer 2

• Accounts for 40-50%
• Sudden onset of pain, D+V
• Pain out of proportion to clinical signs
• Most commonly the SMA

Question 3

What are the risk factors for arterial embolism?

Answer 3

1. AF
2. MI
3. Tachyarrhythmias
4. Endocarditis
5. Cardiomyopathy
6. Ventricular aneurysm
7. Rheumatic fever

Question 4

How does arterial thrombosis as a cause foe mesenteric ischaemia present?

Answer 4

• Post-prandal pain, weight loss, nausea, insidious onset with progression to chronic pain
• “mesenteric angina”

Question 5

What are the risk factors for mesenteric angina?

Answer 5

Atherosclerosis
Raised cholesterol
Oestrogen
Hypercoagulable state

Question 6

Describe non-occlusive mesenteric ischaemia

Answer 6

• Results from a low cardiac output state causing diffuse mesenteric vasoconstriction
• Vasoactive drugs e.g. vasopressin have been implicated
• Associated with poor outcomes - affects the critically unwell

Question 7

Describe mesenteric venous thrombosis

Answer 7

• Acute thrombosis of the SMV and its branches with or without extension to the portal vein
• Pathogensis is attributed to virchows triad
• Occurs in primary or secondary thrombophilia, trauma or local inflammatory states.