Acute mesenteric ischaemia

Question 1

what are the 4 most common causes of mesenteric ischaemia?

Answer 1

• acute mesenteric arterial thrombosis (AMAT)
• acute mesenteric arterial embolism (AMAE) - AF/aneurysm
• Non-occlusive cause e.g. shock
• mesenteric venous thrombosis and congestion

Question 2

what are the risk factors for mesenteric ischaemia?

Answer 2

reversible: smoking/hypertension/hyperlipidaemia
irreversible: AF, thoracic aneurysm

Question 3

what are the clinical features of mesenteric ischaemia?

Answer 3

• poorly localised pain (often seems severe compared to the clinical picture)
• N&V
• late stage can present with perforation

*pay attention to potential embolic sources e.g Arrhythmias

Question 4

which artery is often affected?

Answer 4

Superior mesenteric artery

Question 5

what investigations may be considered in suspected Acute mesenteric ischamia?

what are the relevant findings?

Answer 5

Lab tests:
- ABG (increased lactate level + acidosis in infarction)
- blood tests
LFTS - if coeliac trunk is affected these will be deranged
U&Es
FBC
amylase - may be raised even in ischaemia
clotting factors
group and save

Imaging:
- triple phase CT scan with IV contrast
on CT: oedematous bowel due to ischaemia and vasodilation, loss of bowel wall enhancement, pneumatosis

if perforation is suspected an erect CXR would be performed first

Question 6

how is Ischaemic colitis managed?

Answer 6

surgical interevntion:

Revascularisation:
this decision is made based on the appearance of the bowel on imaging, the appearance of the blood vessels and the state of the patient
this is performed typically through angioplasty however may be performed as an open embolectomy.

excision of necrotic tissue:
this is performed if revascularization is not appropriate. performed as an open laparotomy and requires 24-48 hrs in ITU with potential relook laparotomy considered.

most patients end up with end stomas and probably have short bowel syndrome