Acute Limb Ischaemia

Question 1

Define acute limb ischaemia

Answer 1

Sudden decrease in limb perfusion causing potential threat to limb viability presenting up to 2 weeks following the acute event (>2 weeks = chronic)

Question 2

Name 10 causes acute limb ischaemia

Answer 2

Thrombosis
• atherosclerosis stenosis artery (present within hours)
• arterial graft bypass
• distal aneurysm (present within hours)
• native artery from thrombophilia (later presentation within days)

Embolism
• heart (af,mi)
• proximal aneurysm
• arthero-embolism

Other
• arterial trauma (present within hours)
• aortic/arterial dissection
• arteritis with thrombosis
• HIV vasculopathy
• spontaneous thrombosis associated with hyper coagulability
. Popliteal adventitial cyst with thrombosis
• popliteal entrapment with thrombosis
• vasospasm with thrombosis eg ergotism
• compartment syndrome
• paradoxical emboli (artery not vein)

Question 3

Define embolism

Answer 3

Blood clot, fatty deposit or air bubble that is freely floating piece of thrombus that is carried by the bloodstream until it lodges in blood vessel. Can be fatal

Question 4

Define thrombus

Answer 4

Blood clot that can impede blood flow, larger, stationary,

Question 5

History findings and symptoms acute limb ischaemia? (4)

Answer 5

• Abruptness and time onset of pain, change in severity over time etc - extreme pain
• motor and sensory loss
• history previous vascular surgery, aneurysm, comorbid heart conditions, atherosclerosis etc
• nb presentation < 2 weeks following acute event

Question 6

Physical examination findings acute limb ischaemia?

Answer 6

6 ps
• Pain!
• pulselessness
• pallor
• paraesthesia
• paralysis (poor prognosis)
• poikilothermia (can’t regulate core body temperature)

Question 7

Describe Rutherford’s classification for acute limb ischaemia

Answer 7

• Stage 1: limb viable, not immediately threatened. No sensory loss or muscle weakness, arterial and venous Doppler signal audible
• stage 2a: limb marginally threatened, salvageable with prompt treatment. Minimal (toes) sensory loss or none, no muscle weak, arterial Doppler signal often inaudible
• stage 2b: immediately threatened limb, salvageable with immediate revascularisation. Sensory loss more than toes and associated with pain at rest, mild to moderate muscle weak, arterial Doppler signal usually inaudible
• stage 3: limb irreversibly damaged, major tissue loss or permanent nerve damage inevitable. Profound anesthesia, profound paralysis (rigor mortis ankle ), inaudible arterial and venous Doppler signal

Question 8

Name 3 conditions that mimic acute limb ischaemia

Answer 8

• Systemic shock (especially if associated with chronic occlusive disease)
• phlegmasia cerulean Dolens
• acute compressive neuropathy

Question 9

Investigations for acute limb ischaemia? (2)

Answer 9

Ideally all need imaging like chronic ischaemia but often no time.
• labs: chemistry, FBc, clotting profile, creatinine kinase
• angiography: localises obstruction and helps visualise distal arterial tree. CT angiogram has advantage of speed, convenience, cross-sectional imaging of vessels
Doppler to do Rutherford staging

Question 10

Treatment acute limb ischaemia? (8)

Answer 10

• immediate anticoagulation with iv UFH to prevent thrombus propagation and worsening ischaemia.
• Endo vascular options
-Catheter directed thrombolysis
- thrombectomy (mechanical)
-Angioplasty with or without stenting
• surgical options
- thrombo-embolectomy
- surgical bypass
- fasciotomy (therapeutic for compartment syndrome, diagnostic to confirm non-viable limb, or prophylactic for severe prolonged ischaemia where compartment syndrome anticipated)
• amputation for non-viable limb

Question 11

Name 4 complications of reperfusion of an ischaemic limb

Answer 11

• Compartment syndrome
• renal failure: rhabdomyolysis
• ARDS
• hyperkalemia