Acute limb ischaemia

Question 1

What is acute limb ischaemia

Answer 1

Sudden decrease in limb perfusion tht thratens the viability of the limb
1.5 per 10,000 person yers

Question 2

What are the causes

Answer 2

Thrombosis in situ (60%) - atheroma in artery ruptures and thrombus forms (platelets aggregate due rupture plaque)
Embolisation (30%) - thrombus from a proximal source which travels distally and becomes lodged –> occludes
Trauma (10%) - including compartment syndrome

Question 3

What are the clinical features

Answer 3

6Ps 
Pain 
Pallor 
Pulselessness 
Paraesthesia 
Pershingly Cold 
Paralysis 
*sudden onset

Question 4

What is a sensitive sign of embolic occlusion

Answer 4

Contralateral limb is pulsatile

Question 5

What are the causes of embolisation

Answer 5

Chronic limb ischaemia 
AF
Recent MI 
Symptomatic AAA - back/abdo pain 
Peripheral aneurysms

Question 6

What are the stages of acute limb ischaemia

Answer 6

I - Viable
No immediate threat, no sensory loss, no motor loss, arterial doppler audible, venous doppler audible
IIA- Marginally threatened
Salvageable if promptly treated, minimal sensory loss, no motor deficit, Arterial doppler unaudible, venous doppler audible
IIB - Immediately threatened.
Sensory loss more than toes, Rest pain, Mild/moderate motor deficit, Arterial doopler inaudible, venous doppler audible
III - Irreversible
Major tissue loss, permanent nerve loss, Profound sensory loss, profound motor paralysis, Arterial and venous dopplers inuaudible

Question 7

What are the differentials for an acutely cold leg

Answer 7

critical chronic limb ischaemia - would have had intermittent claudication prior to presentation. pain before this presentation
Acute DVT - warm, red swollen leg NOT COLD
Spinal cord/peripheral nerve compression - legswould be well perfused and pulses present

Question 8

Which investigations would be done

Answer 8

Bedside - BP, ECG, Pulse, sats
Bloods - FBC, U+Es, CRP, LFTs, Lipids, glucose, serum lactate (assess level of ischaemia)
Thrombophilia screen if under 50 and unknown cause
G+S
Imaging - Doppler USS
CT angiography (gold standard) - if salvageable limb can get more info about location and help decide surgical approach

Question 9

How is acute limb ichaemia managed

Answer 9

Initial - A -E assessment

• high flow O2
• 2 wide bore cannulas
• thearpeutic dose of heparin or heparin infusion

Conservative
prolonged course of heparin - needs reg assessment. If no improvement - surgery

Surgical intervention 
IF embolic 
- embolectomy via a forgarty catheter
- local intra-arterial thrombolysis 
- bypass surgery if insufficient flow back 

IF due to thrombotic disease

• local intra-arterial thrombolysis
• angioplasty
• Bypass surgery

Question 10

When is urgent amputation considered

Answer 10

If leg has irreversible ischaemia

• mottled non-blanching appearnace
• hard woody muscles

Question 11

How is the patient managed after an urgent amputation

Answer 11

Surgical HDU

OT and physio with rehab programme

Question 12

What is the long term management for patients with acute limb ischaemia

Answer 12

Decrease CVS risk - regular exercise, smoking cessation and diet
Antiplatelet agent - aspirin, clopidogrel
Treat any underlying conditions predisposing to acute limb iachaemia

Question 13

What are the complications

Answer 13

Mortality rate is 20%
Reperfusion injury - sudden increase in capillary permeability
Can go on to cause compartment syndrome
Release of substances from damaged muscle cells into blood
- K+ - hyperkalaemia
- H+ - acidosis
- Rhabdomyolysis - AKI