GI - Ischaemia (Mesenteric, chronic small bowel and chronic large bowel)

Question 1

What is acute mesenteric ischaemia?

Answer 1

-Sudden decrease in blood supply to the bowel, resulting in bowel ischaemia and, if not promptly treated, rapid gangrene

Question 2

acute mesenteric ischaemia: aetiology

Answer 2

• Thrombus in situ: acute mesenteric arterial thrombosis (atheroclersis as main underlying cause)
• Embolism: acute mesenteric arterial embolism (cardiac causes: arrhythmias, post-MI mural thrombus or prosthetic heart valve)
• Non-occlusive cause: hypovolemic shock, cardiogenic shock
• Venous occlusion and congestion: mesenterc vnous thromosis ( coagulopathy, malignancy or inflammatory disorders)

Question 3

Risk factor for acute mesenteric ischaemia

Answer 3

• Depend on underlying cause

- Embolic causes: smoking, hyperlipidaemia, hypertension (same as chronic mesenteric ischaemia)

Question 4

Acute mesenteric ischaemia: clinical features/presentation

Answer 4

• Nearly always small bowel
• Presents as a triad: acute severe abdo pain (+- PR bleed), rapid hypovolaemia (shock), no abdominal signs
• May be in AF

Question 5

Acute mesenteric ischaemia: differential Dx

Answer 5

• Should always be considered in cases of severe acute abdo

- Peptic ulcer disease, bowel obstruction and symptomatic AAA

Question 6

Acute mesenteric ischaemia: IX bloods and imaging

Answer 6

• Bloods: raised Hb (plasma loss), raised WCC + amylase + persistent metabolic acidosis (raised lactate)
• Imaging: AXR (gassless abdo) and need to do urgert arteriography/CT/MRI angio

Question 7

Acute mesenteric ischaemia: Mx

Answer 7

• Fluids
• ABX
• LMWH
• Laparotomy: resect necrotic bowel

Question 8

Acute mesenteric ischaemia: complications

Answer 8

-Spetic peritonitis

Question 9

Chronic Small Bowel Ischaemia: cause

Answer 9

-Atheroma and low flow state (eg LVF)

Question 10

Chronic Small Bowel Ischaemia: presentation and management

Answer 10

• severe, colicky, post-prandial abdo pain
• PR bleeding
• Malabsorption
• Wt loss
• Mx: angioplasty

Question 11

Chronic large bowel ischaemia: cause

Answer 11

-follows low flow in IMA territory

Question 12

Chronic large bowel ischaemia: presentation

Answer 12

• Lower, left sided abdo pain
• bloody diarrhea
• pyrexia
• tachycardia

Question 13

Chronic large bowel ischaemia: Ix bloods and imaging (notable results)

Answer 13

• Bloods: raised WCC
• Ba enema: thumb-printing
• MR angiography

Question 14

Chronic large bowel ischaemia: complications and Mx

Answer 14

Mx: usually conservative (fluids and ABX) or angioplasty and endovascular stenting
-Complications: may lead to peritonitis/septic shock or form strictures in long term