Acute Mesenteric Ischaemia Flashcards
What is AMI?
Sudden decrease in the blood supply to the bowel
This leads to bowel ischaemia and if not treated rapidly death.
Most common causes of AMI
Thrombus in situ called Acute Mesenteric Arterial Thrombosis AMAT
Embolism called Acute Mesenteric Arterial Embolism AMAE (50%)
Non-occlusive cause called Non-occlusive Mesenteric Ischaemia NOMI
Venous occlusions and congestion called Mesenteric Venous Thrombosis MVT
Rarer causes like Takayasu’s, fibromuscular dysplasia, PAN, thoracic aortic dissections
Risk factors specifically for AMAE
Smoking
Hyperlipidaemia
HTN
Clinical features
Generalised abdominal pain out of proportion to the clinical findings
Diffuse and constant pain + N+V
Examination findings
Non-specific tenderness
No specific clinical signs
If in late stages might have features of globalised peritonism.
AF or heart murmurs might be heard
Dx
Peptic ulcer disease
Bowel perforation
Symptomatic AAA
Lab tests
ABG to assess degree of acidosis and serum lactate
Routine bloods with FBC, U&Es, clotting, amylase (exclude pancreatitis even if it can be increased in mesenteric ischaemia), LFTs
G&S
Definitive diagnosis
CT scan with IV contrast (CT angiography)
Oral contrast should be avoided in cases of mesenteric ischaemia due to difficulty in assess for bowel wall enhancement.
CT scan with IV contrast findings
A tripe phase scan with thin slices in arterial phase.
Show oedematous bowel secondary to ischaemia and vasodilatation.
Progression to loss of bowel wall enhancement and then pneumatosis
Initial management
A surgical emergency so require urgent resus with early senior involvement
IV fluids + catheter insertion
Fluid balance chart
In confirmed cases -> broad spectrum abx due to risk of faecal contamination in case of perforation of the ischaemic bowel and bacterial translocation
What determines which surgical approach should be done?
Location, timing and severity
Surgical approaches
Excision of necrotic or non-viable bowel
Revascularisation of the bowel
When should excision of necrotic or non-viable bowel be done?
If not suitable for revascularisation
When should revascularisation of the bowel be done?
Depending on the state of the patient, the bowel and the angiographic apperance of the mesenteric vessels.
Explain how revascularisation of the bowel is done.
Removal of any thrombus or embolism via radiological intervention
Done through angioplasty due to risk of aortic contamination in open surgery.
