MRCS Core Knowledge: Acute Limb Ischaemia

04/09/14 16:15 Filed in: MRCS Knowledge

MRCS Knowledge: Acute Limb Ischaemia



MRCS Part B Questions


Today’s MRCS Knowledge looks at the commonly tested topic of acute limb ischaemia.

Background

Sudden onset arterial occlusion with no time for collateral vessel formation (unless pre existing occlusive disease) resulting in inadequate perfusion to distal tissues

Causes

Acute Thrombosis In-Situ (60%)
  • Acute occlusion in a vessel with pre-existing atherosclerosis
  • Risk factors: dehydration, malignancy, hypotension, prothrombotic disorders

Emboli (30-40%)
  • Cardiac cause (80%): AF, MI, prosthetic/damaged heart valves
  • Also from aneurysm, tumour, foreign body

Other causes
  • Trauma, peripheral aneurysm (popliteal), dissecting aneurysm

Presentation

The Six Ps:

  • Pain
  • Pallor
  • Pulselessness
  • Perishing Cold
  • Paraesthesia
  • Paralysis

Thrombosis in-situ: history of intermittent claudication, slower onset, no embolic source, contralateral limb affected

Embolic: no claudication history, rapid onset with complete occlusion, cardiac source e.g. AF, murmur, MI

Onset of fixed mottling of skin implies irreversibility

Management

Immediate: oxygen and IVI fluids, analgesia and heparinise, treat underlying cardiac conditions

Thrombosis in-situ: thrombolysis, angioplasty, bypass surgery
Embolic: embolectomy, thrombolysis

Amputation if irreversible

Complications

Loss of limb (40%): irreversible tissue damage at 6hrs, death (20%), complications from thrombolysis: CVE, retroperitoneal bleed

Prognosis dependent on underlying cause, generally poor

Further Info:
For further info and commonly asked questions on acute limb ischaemia be sure to sign up to the MRCS Part B Questions Bank

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