Acute limb ischaemia

Question 1

What is acute limb ischaemia?

Answer 1

Sudden decrease in limb perfusion that threatens the viability of the limb, by occlusion of the arterial supply

Question 2

What are the three classifications of limb ischaemia?

Answer 2

immobilisation, thrombosis in situ or trauma

Question 3

What is embolisation in limb ischaemia?

Answer 3

whereby a thrombus from a proximal source travels distally to occlude the artery, this is the most common, may be due to AF, Post MI mural thrombus, AAA, prosthetic heart valves

Question 4

What is thrombosis in situ in limb ischaemia?

Answer 4

where an atheroma plaque in the artery ruptures and a thrombus forms on the plaque cap

Question 5

Give an example of trauma that can cause limb ischaemia?

Answer 5

Compartment syndrome

Question 6

What are the 6Ps in limb ischaemia?

Answer 6

Pain
Pallor
Pulselessness
paraesthesia
Perishingly cold
Paralysis

Question 7

What should be explored in the history of someone with potential acute limb ischaemia?

Answer 7

ask about chronic limb ischaemia, atrial fibrillation, recent MI, peripheral aneurysms, symptomatic AAA

Question 8

What are some differential diagnosis for acute limb ischaemia?

Answer 8

Critical choleric limb ischaemia, acute DVT, spinal cord or peripheral nerve compression

Question 9

What are the investigations for acute limb ischaemia?

Answer 9

serum lactate, thrombophilia screen, group and save, ECG, doppler ultrasound of both limbs and CT angiography, if salvageable then CT arteriography can show where the occlusion is and whether to do a femoral or popliteal incision

Question 10

What is the initial management for acute limb ischaemia?

Answer 10

surgical emergency, complete arterial occlusion will have irreversible tissue damage within 6 hours, so high flow oxygen, IV access, heparin

Question 11

What is the surgical intervention for acute limb ischaemia?

Answer 11

embolectomy, intra-arterial thrombolysis, bypass surgery, thryomoylsis, angioplasty, if irreversible then urgent amputation,

Question 12

What is the long term management of acute limb ischaemia?

Answer 12

regular exercise, smoking cessation, weight loss, anti-platelets, low dose aspirin, clopidogrel, occupational therapy, physiotherapy and long term rehabilitation

Question 13

What are the complications of acute limb ischaemia?

Answer 13

mortality rate of around 20% due to the reperfusion injury and compartment syndrome which leads to necrotic cells which release K+ causing Hyperkalaemia, this then causes MI, also release of H+ and myoglobin