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Acute Limb Ischemia (ALI)

Clinical Subject Page

Acute Limb Ischemia (ALI)

ICD-10

I74.3

Specialty

Cardiology

Onset

Acute

Reviewed

July 2026

On This Page

Overview

Acute limb ischemia (ALI) is a vascular emergency caused by a sudden reduction in arterial blood flow to a limb, leading to ischemia of less than 2 weeks’ duration. Without rapid treatment, it can result in permanent limb damage or amputation.

Etiology & Risk Factors

  • -Etiology for Acute Limb Ischemia (ALI)

    • Arterial thrombosis (most common)
    • Arterial embolism (especially from atrial fibrillation)
    • Trauma or vascular injury
    • Aortic dissection and other nonthromboembolic cause

    –Risk Factors for Acute Limb Ischemia (ALI)

    • Atherosclerosis
    • Atrial fibrillation
    • Recent myocardial infarction
    • Previous vascular stent or graft
    • Hypercoagulable states
    • Trauma or recent arterial catheterization

Pathophysiology

  • Sudden arterial occlusion (usually by thrombosis or embolism) causes an abrupt loss of blood flow to the limb.
  • Reduced tissue perfusion leads to ischemia of muscles and nerves.
  • Prolonged ischemia results in tissue necrosis, causing sensory and motor deficits and potentially irreversible limb damage if blood flow is not restored promptly.

Clinical Presentation

  • Patients with Acute Limb Ischemia (ALI) typically present with the 6 Ps:

    • Pain (sudden, severe)
    • Pallor
    • Pulselessness
    • Paresthesia
    • Paralysis
    • Poikilothermia (cold limb)

History Taking

  • Was it sudden or gradual?
  • Where is the pain?
  • Is the pain severe?
  • Have you noticed your limb becoming cold or pale?
  • Do you have numbness or tingling?
  • Do you have weakness or difficulty moving the limb?
  • Have you had leg pain while walking (claudication) before this?
  • Do you have a history of atrial fibrillation, heart attack, or peripheral arterial disease?
  • Have you had any recent trauma or vascular procedure?

Physical Examination

    • Inspect the limb for color (pallor/mottling).
    • Assess temperature (cold limb).
    • Palpate and compare distal pulses with the opposite limb.
    • Check capillary refill.
    • Assess sensation (paresthesia/sensory loss).
    • Assess motor function (weakness or paralysis).
    • Use a handheld Doppler to assess arterial blood flow if pulses are absent or reduced.

Investigations

    • Handheld Doppler – best initial bedside test for Acute Limb Ischemia (ALI).
    • Ankle–brachial index (ABI).
    • CT angiography (CTA) – most common imaging to identify the site of occlusion.
    • Duplex ultrasound or digital subtraction angiography (when indicated).
    • Laboratory tests: CBC, coagulation profile, CMP, blood gas, serum lactate, CPK/myoglobin.
    • ECG and echocardiography to identify a cardiac source of emboli.

    Important: If the limb is clearly threatened, do not delay revascularization for imaging.

Diagnosis

  • Diagnosis is based on clinical suspicion and confirmation with bedside vascular assessment.

    • Clinical diagnosis: Sudden onset of the 6 Ps (pain, pallor, pulselessness, paresthesia, paralysis, poikilothermia).
    • Confirmatory bedside test: Handheld Doppler to assess arterial blood flow.
    • Confirmatory imaging: CT angiography (CTA) is the most common imaging modality to identify the site of arterial occlusion.
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Management

  • Urgent vascular surgery consultation.
  • Start IV unfractionated heparin as soon as possible (unless contraindicated).
  • Provide analgesia and supportive care.
  • Do not delay treatment for imaging if the limb is threatened.
  • Revascularization (endovascular or surgical) for viable/threatened limbs.
  • Amputation for a nonviable limb.
  • Treat the underlying cause (e.g., atrial fibrillation, trauma, infective endocarditis).

Complications

  • Permanent nerve damage (sensory loss, muscle weakness, paralysis)
  • Irreversible tissue necrosis
  • Limb loss (amputation) due to irreversible ischemia
  • Reperfusion injury (postischemic syndrome) after restoration of blood flow

Prognosis

  • Good if diagnosed and treated promptly with rapid restoration of blood flow.
  • Delayed treatment increases the risk of permanent nerve damage, irreversible tissue necrosis, and limb loss (amputation).
  • Prognosis depends on limb viability at presentation and the time to revascularization.

Key Points / Clinical Pearls

  • Acute Limb Ischemia (ALI) is a vascular emergency.
  • Think of the 6 Ps: Pain, Pallor, Pulselessness, Paresthesia, Paralysis, Poikilothermia.
  • Handheld Doppler is the best initial bedside test; CTA is the common imaging test.
  • Do not delay treatment for imaging if the limb is threatened.
  • Start IV unfractionated heparin (unless contraindicated) and obtain urgent vascular surgery consultation.
  • Early revascularization is essential to save the limb.