Clinical Subject Page
Acute Limb Ischemia (ALI)
ICD-10
I74.3
Specialty
Cardiology
Onset
Acute
Reviewed
July 2026
On This Page
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OverviewOverview
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Etiology & Risk FactorsEtiology & Risk Factors
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PathophysiologyPathophysiology
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Clinical PresentationClinical Presentation
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History TakingHistory Taking
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PhysicalExaminationPhysicalExamination
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InvestigationsInvestigations
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DiagnosisDiagnosis
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ManagementManagement
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ComplicationsComplications
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PrognosisPrognosis
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Key Points / Clinical PearlsKey Points / Clinical Pearls
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.
Teaching point
Patients typically present with the 6 Ps:
Pain
Pallor
Pulselessness
Paresthesia
Paralysis
Poikilothermia (cold limb)
Etiology & Risk Factors
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-Etiology
- Arterial thrombosis (most common)
- Arterial embolism (especially from atrial fibrillation)
- Trauma or vascular injury
- Aortic dissection and other nonthromboembolic cause
–Risk Factors
- 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
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Patients with acute limb ischemia typically present with the 6 Ps:
- Pain (sudden, severe)
- Pallor
- Pulselessness
- Paresthesia
- Paralysis
- Poikilothermia (cold limb)
Important Note
Acute limb ischemia is a vascular emergency. Severe pain suggests the limb is at risk, and treatment should not be delayed for imaging. Urgent vascular surgery assessment is required.
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
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- 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
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- Handheld Doppler – best initial bedside test.
- 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
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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.
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 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.