Acute Limb Ischaemia

Question 1

What is it?

Answer 1

A sudden decrease in limb perfusion that threatens the viability of the limb.

Question 2

Aetiology?

Answer 2

Thrombosis in situ: ruptured plaque

Embolism: thrombus from proximal source has travelled distally

Trauma: including compartment syndrome

Question 3

Clinical features?

Answer 3

6 Ps

Pain, pallor, pulseless, perishingly cold, paresthesia, paralysis

SUDDEN ONSET

Question 4

What is the scoring system?

Answer 4

Rutherford Scoring

Question 5

In the history, what should be explored?

Answer 5

• Potential causes of the event
• (chronic limb ischaemia, atrial fibrillation, recent MI (resulting in a mural thrombus), or a symptomatic AAA (ask about back/abdominal pain) and peripheral aneurysms)

Question 6

Investigations?

Answer 6

Routine bloods (including serum lactate), group and save and an ECG

Dopplet USS followed by considering a CT Angio

Question 7

Management?

Answer 7

It is a surgical emergency. Will lead to irreversible ischaemic damage in 6 hours.

• Start the patient on high-flow oxygen
• Ensure adequate IV access
• A therapeutic dose heparin or preferably a bolus dose then heparin infusion should be initiated as soon as is practical.

May need surgical intervention:

• Embolectomy via a Fogarty catheter
• Local intra-arterial thrombolysis*
• Bypass surgery (if there is insufficient flow back)

If the cause is due to thrombotic disease, the options are:

• Local intra-arterial thrombolysis
• Angioplasty (Fig. 3)
• Bypass surgery

Question 8

Complications?

Answer 8

Reperfusion injury; sudden increase in capillary permeability can result in:

• Compartment syndrome
• Release of substances from the damaged muscle cells, such as:
  
  • K+ ions causing hyperkalaemia
  • H+ ions causing acidosis
  • Myoglobin, resulting in significant AKI