Bowel Ischaemia - Mesenteric Ischaemia

Question 1

Definition

Answer 1

Ischaemia of the small bowel
The coeliac trunk supplies the proximal part of the duodenum where as the Superior Mesenteric Artery supplies the rest of the small bowel + 2/3 of transverse colon

Question 2

Types of mesenteric ischaemia

Answer 2

AMI = acute mesenteric ischaemia = acute attack = ‘abdominal MI’
CMI = chronic mesenteric ischaemia = long lasting, over months = ‘abdominal angina’

Question 3

Epidemiology

Answer 3

Age: > 40
WOMEN

Question 4

Risk factors

Answer 4

A.fib
Previous MI
Hypercoagulable state
Infective endocarditis
Vasculitis
Hypoperfusion

Chronic:
Atherosclerosis:
- HTN,
- Hypercholesterolaemia,
- Diabetes
Increasing age
Family history
Smoking

Question 5

Aetiology

Answer 5

SMA THROMBOSIS = MC
SMA Embolism
Venous thrombosis = rare = Px history of hypercoagulability
Non-occlusive = Hypoperfusion
- trauma
- sepsis
- HF

Question 6

Signs

Answer 6

Often no abdominal signs (e.g. guarding, rebound tenderness)
Absence of bowel sounds as motility decreases = late sign
Digital rectal exam: bleeding
Epigastric bruit on auscultation
Hypotensive + tachycardic

Question 7

Symptoms

Answer 7

Abdominal pain:
- acute ischaemia: severe, out of proportion to abdominal signs
- chronic ischaemia: colicky, intermittent, post-prandial and described as ‘intestinal angina’
Nausea + Vomiting
Diarrhoea +/- rectal bleeding
Fever
Weight loss (chronic)

Question 8

Acute mesenteric ischaemia triad

Answer 8

1. Acute, severe, abdominal pain = central/right iliac fossa
2. Diarrhoea and vomiting
3. Potential embolic source
   RAPID HYPOVOLAEMIC SHOCK

Question 9

Diagnosis

Answer 9

FIRST LINE: Bloods
- FBC = anaemia
- U + E’s = assesses for pre-renal AKI due to hypovolaemia
- VBG = metabolic acidosis and raised lactate is suggestive of bowel ischaemia and necrosis
- Coagulation screen = assess for possible hypercoagulability
GOLD STANDARD (Chronic) : CT angiogram
GOLD STANDARD (Acute) : Contrast CT

Question 10

Treatment

Answer 10

AMI = SURGICAL EMERGANCY = Infarcted bowel = Bowel resection
CMA = FIRST LINE = Endovascular procedures (i.e. percutaneous mesenteric artery stenting)
SECOND LINE = Open surgery (endarterectomy, re-implantation or bypass grafting)

Question 11

Complication

Answer 11

Bowel infarction and perforation
Short bowel syndrome
Strictures

Question 12

Chronic mesenteric ischaemia TRIAD

Answer 12

Central colicky abdominal pain after eating (starting around 30 minutes after eating and lasting 1-2 hours)
Weight loss (due to food avoidance, as this causes pain)
Abdominal bruit may be heard on auscultation