Acute Limb Ischemia

Definition and Epidemiology

• Acute limb ischemia (ALI) is a sudden decrease in blood flow to the extremities, resulting in tissue hypoxia and potential necrosis.
• Incidence: 1 in 100,000 per year, with a mortality rate of 10-20% within 30 days.

Etiology

• Embolism (70-80%): cardiac thrombi, paradoxical emboli, or in situ thrombosis.
• Thrombosis (20-30%): atherosclerosis, aneurysms, or hypercoagulable states.
• Trauma, iatrogenic injury, or vasculitis (rare).

Clinical Presentation

• Sudden onset of limb pain, often severe and out of proportion to physical findings.
• Coldness, numbness, or tingling in the affected limb.
• Weakness or paralysis.
• Decreased or absent pulses.
• Pale or cyanotic skin.
• Delayed capillary refill (>3 seconds).

Diagnosis

• Clinical evaluation: focused history, physical examination, and pulse examination.
• Ankle-brachial index (ABI): <0.9 indicates ischemia.
• Imaging:
  • Doppler ultrasound: assesses blood flow and vessel patency.
  • Computed tomography angiography (CTA) or magnetic resonance angiography (MRA): evaluates vascular anatomy and detects occlusions.

Management

• Emergent: immediate revascularization, anticoagulation, and analgesia.
• Revascularization:
  • Thrombolysis: pharmacological or mechanical.
  • Endovascular interventions: angioplasty, stenting, or thrombectomy.
  • Surgical intervention: embolectomy, bypass grafting, or amputation (as a last resort).
• Supportive care: fluid resuscitation, pain management, and wound care.

Complications

• Tissue necrosis and gangrene.
• Rhabdomyolysis.
• Renal failure.
• Sepsis and multi-organ failure.

Acute Limb Ischemia (ALI)

• Sudden decrease in blood flow to the extremities, resulting in tissue hypoxia and potential necrosis.

Epidemiology

• Incidence: 1 in 100,000 per year
• Mortality rate: 10-20% within 30 days

Etiology

• Embolism: 70-80% of cases, caused by cardiac thrombi, paradoxical emboli, or in situ thrombosis
• Thrombosis: 20-30% of cases, caused by atherosclerosis, aneurysms, or hypercoagulable states
• Trauma, iatrogenic injury, or vasculitis: rare causes

Clinical Presentation

• Sudden onset of severe limb pain
• Coldness, numbness, or tingling in the affected limb
• Weakness or paralysis
• Decreased or absent pulses
• Pale or cyanotic skin
• Delayed capillary refill (>3 seconds)

Diagnosis

• Clinical evaluation: focused history, physical examination, and pulse examination
• Ankle-brachial index (ABI): used to diagnose and monitor ALI