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Year 3 > Intestinal ischaemia (GI) > Flashcards

Intestinal ischaemia (GI) Flashcards

1
Q

Define intestinal ischaemia.

A

Obstruction of mesenteric vessel leading to bowel ischaemia and necrosis

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2
Q

What are the three types of intestinal ischaemia?

A
  • acute mesenteric ischaemia - acute inadequate blood flow to the small intestine
  • chronic mesenteric ischaemia - constant/episodic hypoperfusion of the small intestine
  • ischaemic colitis AKA colonic ischaemia - hypoperfusion of the large bowel
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3
Q

What artery is compromised in acute mesenteric ischaemia?

A

Superior mesenteric artery

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4
Q

What is acute mesenteric ischaemia associated with? (4)

A
  • embolism (50%) - left-sided thrombus OR from spontaneous/iatrogenic rupture and embolisation from an aortic atherosclerotic plaque/aneurysm OR atrial fibrillation
  • arterial thrombosis (15-20%) - atherosclerosis at origin of SMA, can also result in subacute/chronic ischaemia
  • venous thrombosis (5%) - cirrhosis/portal hypertension
  • hypoperfusion (20%) i.e. non-occlusive ischaemia - shock/hypotension
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5
Q

What is chronic mesenteric ischaemia usually caused by?

A

Atherosclerosis

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6
Q

Which artery is usually compromised in ischaemic colitis?

A

Inferior mesenteric artery

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7
Q

Which areas are at high risk of ischaemic colitis?

A
  • near splenic flexure
  • 2/3 transverse colon at high risk due to being watershed areas
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8
Q

What are some risk factors associated with ischaemic colitis? (5)

A
  • age
  • AF
  • smoking
  • hypertension
  • diabetes
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9
Q

Which out of the three forms of intestinal ischaemia is most common and has the most favourable prognosis?

A

Ischaemic colitis AKA colonic ischaemia

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10
Q

What forms can intestinal ischaemia present as? (3)

A
  • transient reversible ischaemia
  • chronic irreversible ischaemia
  • acute fulminant ischaemia
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11
Q

What are the clinical features of intestinal ischaemia? (9)

A
  • abdominal pain and tenderness:
    • out of proportion to examination
    • postprandial / post-exercise
    • colicky
  • haematochezia (fresh rectal bleeding)/melaena - ischaemic colitis
  • diarrhoea
  • nausea
  • weight loss (chronic)
  • abdominal bruits
  • vasculitis
  • anaemia - pallor, dyspnoea, light-headed
  • food fear (sitophobia) - chronic
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12
Q

What is post-prandial abdominal pain AKA in chronic mesenteric ischaemia?

A

Intestinal angina - due to atherosclerosis

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13
Q

In which type of intestinal ischaemia is rectal bleeding common?

A

Ischaemic colitis

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14
Q

What is characteristic of acute mesenteric ischaemia?

A

Sudden, severe abdominal pain out of keeping with physical exam findings

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15
Q

What is the classic triad of chronic mesenteric ischaemia?

A
  • severe, colicky post-prandial pain (intestinal angina)
  • abdominal bruit
  • weight loss
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16
Q

What are some risk factors for intestinal ischaemia? (5)

A
  • age
  • AF, MI, SHD, vasculitis, hypercoagulable states
  • smoking
  • hypertension
  • diabetes
17
Q

What are the first-line investigations for intestinal ischaemia? (5)

A
  • CT scan with contrast / CT angiogram
  • AXR
  • ABG/VBG and serum lactate
  • FBC
  • U&Es
18
Q

What does CT with contrast/CT angiogram show in intestinal ischaemia? (6)

A
  • bowel wall thickening
  • bowel dilation
  • pneumatosis intestinalis (air between walls of intestine)
  • portal venous gas
  • occlusion of mesenteric vasculature
  • bowel wall thickening with thumbprinting suggestive of submucosal oedema or haemorrhage
19
Q

What does AXR show in intestinal ischaemia?

A

Thumbprint on barium enema for ischaemic colitis

20
Q

What do we see in ABG/VBG in intestinal ischaemia?

A

Metabolic acidosis with high lactate

(Low HCO3-)

21
Q

What might FBC show in intestinal ischaemia? (3)

A
  • leukocytosis
  • anaemia
  • evidence of haemoconcentration
22
Q

What might U&Es show in intestinal ischaemia?

A

Uraemia and elevated creatinine

23
Q

What are some differential diagnoses for intestinal ischaemia? (9)

A
  • infectious colitis (colonoscopy)
  • ulcerative colitis
  • Crohn’s disease (chronic diarrhoea, WL, RLQ pain)
  • diverticular disease
  • large bowel obstruction (can lead to ischaemia)
  • small bowel obstruction (N&V, distension)
  • peptic ulcer disease (epigastric, less severe)
  • acute pancreatitis
  • gastroenteritis
24
Q

What is the management for acute mesenteric ischaemia / infarction, perforation or peritonitis on CT? (4)

A
  • fluid resuscitation
  • supportive measures - O2, NBM, NG tube with decompression
  • empirical Abx
  • urgent laparotomy
25
Q

How do we manage a SMA embolus with infarction/perforation/peritonitis (acute mesenteric ischaemia)?

A

Open embolectomy or arterial bypass +/- bowel resection

26
Q

How do we manage a SMA thrombosis with infarction/perforation/peritonitis (acute mesenteric ischaemia)?

A

Antegrade and retrograde bypass grafting, aortic re-implantation of SMA, and transarterial and transaortic mesenteric endarterectomy

27
Q

How do we manage non-occlusive intestinal ischaemia with infarction/perforation/peritonitis?

A

Correct medical causes (heart failure), arrhythmia, shock or haemodialysis

28
Q

How do we manage venous mesenteric ischaemia with infarction/perforation/peritonitis?

A

Anticoagulation with heparin then switching to warfarin (for 3-6 months)

Surgery indicated if infarction/peritonitis

29
Q

How do we manage fulminant colitis?

A

Subtotal or total colectomy

30
Q

How do we manage intestinal ischaemia with no evidence of infarction, perforation or peritonitis?

A
  • SMA embolus/thrombosis = endovascular therapy (thrombolysis)
  • vasculitis-associated = corticosteroid therapy - methylprednisolone
31
Q

How do we manage chronic intestinal ischaemia?

A
  • if severe malnutrition - antegrade and retrograde bypass grafting, aortic re-implantation of SMA, transarterial and transaortic mesenteric endarterectomy
  • percutaneous transluminal mesenteric angioplasty alone/with stent insertion
32
Q

How do we manage ischaemic colitis? (5)

A
  • fluid resuscitation
  • Abx
  • conservative management
  • consider anticoagulation
  • consider segmental resection and stoma
33
Q

What are some complications of intestinal ischaemia? (3)

A
  • sitophobia (fear of food) –> malnutrition
  • stricture
  • short bowel syndrome

Year 3 (145 decks)

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