Ischaemic bowel disease

Question 1

Frequent site of ischaemic colitis?

Answer 1

Splenic flexure. Site at which arterial anastomoses are least well developed.

Question 2

What are the clinical features of ischaemic colitis?

Answer 2

Symptoms: Acute left sided abdominal pain, dark red rectal bleeding.
Signs: fever, hypotension, abdominal tenderness.

Question 3

Ix in ischaemic colitis?

Answer 3

AXR: distended splenic flexure (oedematous mucosa may be detected).
CT/barium enema: thumb printing of mucosa apparent.

Question 4

Mx of ischaemic colitis?

Answer 4

Spontaneous resolution.

Occasionally gangrene requires emergency surgery (ischamia –> stricture –> gangrene).

Question 5

What is ischaemic bowel diseae?

Answer 5

Diverse group of heterogenous disorders that may be acute or chronic; occlusive or non-occlusive in aetiology; result in decreased blood flow to GIT.

Question 6

What are the forms of arterial compromise precipitating ischaemic bowel disease?

Answer 6

• Embolism: 50% cases.
• Thrombosis: 15-20%
• Vasculitis
• External compression: rare

Question 7

Describe the pathophysiology of arterial thrombosis precipitating ischaemic bowel.

Answer 7

Thrombus occurring as progression of atherosclerosis at origin of SMA. Sub acute or chronic ischaemia may result from partial occlusion of the vessel.

Question 8

Which conditions can lead to vasculitis causing ischaemia of the bowel?

Answer 8

RA, polyarteritis nodosa, SLE, dermatomyositis, Takayasu.

Question 9

What is the aetiology of ischaemic bowel disease?

Answer 9

• Arterial compromise
• Venous compromise
• Hypoperfusion (shock/hypotension/surgery/infection).

Question 10

Which areas in the bowel are watershed areas?

Answer 10

-Splenic flexure
-Recto-sigmoid junction
Collaterisation of blood flow may be limited

Question 11

What occurs as a result of bowel ischaemia?

Answer 11

Mucosal sloughing, ulceration, bacterial translocation.
Reperfusion injury may occur.
Healing may result in stenosis or stricture.

Question 12

Which artery is generally affected by thromboembolic events leading to ischaemic bowel?

Answer 12

SMA. Lies more vertically on the aorta than the other vessels (IMA and coeliac artery) which are positioned more obliquely.

Question 13

What are the RFx for ischaemic bowel disease?

Answer 13

• Old age
• Smoking
• Hypercoaguability
• AF
• MI
• Vasculitis

Question 14

Ix in ischaemic bowel disease?

Answer 14

FBE: leukocytosis, anaemia, haemoconcentration
ABGs: acidosis, elevated lactate
Chemistry panel: acidosis, uraemia, elevate creatinine
ECG: AF, arrhythmia, MI
CXR: free air if perforation
AXR: air fluid levels, bowel dilation, bowel wall thickening
Colonoscopy: mucosal sloughing/friability, mucosal petechiae, erosions/ulcerations.

Question 15

DDx ischaemic bowel disease?

Answer 15

Infectious colitis, UC/CD, diverticular disease

Question 16

How should acute ischaemic bowel be treated with evidence of infarction/perforation/peritonitis?

Answer 16

• Resuscitation and supportive measures
• Empiric ABx (ceftriaxone 1g IV/24 + metronidazole 500mg IV tds).
• Laparoscopy

Question 17

What are the supportive measures needed in ischaemic bowel disease?

Answer 17

• Bowel rest
• NGT
• NPO status
• IV fluids
• O2 as required
• Correct hypotension/CCF/arrhythmias
• Close observation (e.g. for peritonitis)

Question 18

How should acute ischaemic bowel be managed with no evidence of infarction/perforation/peritonitis?

Answer 18

• Supportive measures

- Empiric ABx