Intestinal Ischaemia

Question 1

What is intestinal ischaemia?

Answer 1

Obstruction of a mesenteric vessel leading to bowel ischaemia + necrosis

Question 2

What are the 3 main types of intestinal ischaemia?

Answer 2

Acute mesenteric ischaemia
Chronic mesenteric ischaemia (intestinal angina)
Ischaemic colitis

Question 3

Describe the epidemiology of mesenteric ischaemia

Answer 3

UNCOMMON
More common in the ELDERLY
Chronic: F > M
RF: HTN, hyperlipidaemia, smoking, diabetes, AF

Question 4

List 3 features of presentation of acute mesenteric ischaemia

Answer 4

Acute severe, constant abdo pain, disproportionate to findings
N+V
Diarrhoea (+blood later) s + rapid hypovolaemia

Question 5

List 5 features of presentation of chronic mesenteric ischaemia

Answer 5

Dull, colicky post-prandial abdo pain (gut claudication)
Weight loss (eating hurts + malabsorption)
Upper abdo bruit
Bloating, nausea
Concurrent vascular co-morbidities

Question 6

Give 3 symptoms of ischaemic colitis

Answer 6

Sudden onset, crampy abdo pain (often LIF)
N+V
Bloody diarrhoea

Question 7

What is diagnosis of intestinal ischaemia based on?

Answer 7

Clinical suspicion or after laparotomy

Question 8

What investigations may be performed in acute mesenteric ischaemia?

Answer 8

High lactate, high LDH, high creatine kinase
Leukocytosis
Metabolic acidosis
CT angiography confirms dx

Question 9

What investigations may be performed in chronic mesenteric ischaemia?

Answer 9

Bloods may show malabsorption/ dehydration

CT angiography confirms dx

Question 10

What is a watershed area? What occurs in systemic hypo perfusion?

Answer 10

A region that receives a dual blood supply from the most distal branches of 2 large arteries.
Systemic hypoperfusion: susceptible to ischaemia as supplied by most distal branches.

Question 11

What is the firstline investigation for suspected acute intestinal ischaemia?

Answer 11

CT

Should be obtained early.

Question 12

What 3 features may be seen on colonoscopy in ischaemic colitis?

Answer 12

Submucosal oedema
Ulceration
Gangrene

Question 13

What is Acute mesenteric ischemia?

Answer 13

Acute inadequate blood flow to the small intestine that can result in bowel infarction

Question 14

What is Chronic mesenteric ischaemia?

Answer 14

Reduced blood supply to the small bowel which gradually deteriorates over time as a result of atherosclerosis

Question 15

Describe the pathophysiology of ischaemic colitis

Answer 15

Intestinal blood flow of SMA +/- IMA is suddenly compromised
Intestinal hypoxia + wall damage
Mucosal inflammation +/- bleeding
May progress to infarction + necrosis (gangrenous type)
Disruption of mucosal barrier + perforation
Release of bacteria, toxins, vasoactive substances
Life-threatening sepsis

Question 16

Which areas are at high risk of colonic ischaemia?

Answer 16

Watershed areas:
Splenic flexure
Rectosigmoid junction

Question 17

Describe the epidemiology of ischaemic colitis

Answer 17

Most common form of intestinal ischemia
Mainly occurs > 60 years
80–85%= mild, nongangrenous form

Question 18

Which conditions may acute arterial emboli arise from causing Acute mesenteric ischemia?

Answer 18

AF
MI
Valvular heart disease
Endocarditis

Question 19

Describe the pathophysiology of Acute mesenteric ischemia

Answer 19

Sudden interruption of blood flow to small bowel
Intestinal hypoxia
Hemorrhagic infarction + necrosis
Disruption of mucosal barrier + perforation
Release of bacteria, toxins, vasoactive substances
Life-threatening sepsis

Question 20

List 6 causes of reduced flow through the IMA in ischaemic colitis

Answer 20

Occlusion by thrombus/embolus 
Iatrogenic ligation  
Hypovolaemia 
Small vessel vasculitis in younger patients 
Vasospasm e.g. cocaine 
Hypercoagulable states

Question 21

What investigations may be performed in ischaemic colitis?

Answer 21

If severe; High lactate, high LDH, high creatine kinase, Leukocytosis, Metabolic acidosis
AXR: Bowel wall thickening
CT: wall thickening + gas in wall, thumbprinting
Colonoscopy: confirms dx + assesses severity

Question 22

What is ischaemic colitis?

Answer 22

Hypoperfusion of the LARGE bowel
Mostly transient + self-limiting (nongangrenous), but can lead to severe acute ischemia with bowel infarction (gangrenous)