Acute limb ischemia

Last updated: May 26, 2023

Summarytoggle arrow icon

Acute limb ischemia (ALI) is a vascular emergency in which the arterial blood supply to one or more extremities is critically reduced. Arterial thrombosis and cardiac emboli are responsible for the majority of cases. The typical signs and symptoms of ALI include pain, pallor, pulselessness, poikilothermia, paralysis, and paresthesia of the limb distal to the site of vascular occlusion (the 6 Ps). Diagnosis relies on examination and arterial Doppler studies. Clinical findings in combination with Doppler studies are then used to categorize the limb as viable, threatened, or nonviable. Further imaging studies, e.g., digital subtraction angiography, should only be performed if they do not result in treatment delays. Management of viable and threatened limb ischemia begins with intravenous heparin followed by revascularization. Irreversible limb ischemia will inevitably progress to gangrene and requires amputation of the nonviable parts of the limb. Whether long-term anticoagulation and/or further diagnostic studies are required depends on the suspected etiology (e.g., echocardiography in suspected left atrial thrombus formation).

Etiologytoggle arrow icon


Clinical featurestoggle arrow icon


Subtypes and variantstoggle arrow icon

Leriche syndrome (aortoiliac occlusive disease)

Occlusion at the level of the aortic bifurcation or bilateral occlusion of the iliac arteries that usually presents with:

Hair tourniquet syndrome

  • Definition: : a condition in which a hair or thread becomes wound around an appendage tightly, putting the appendage at risk of ischemic damage
  • Epidemiology: usually affects infants
  • Pathophysiology: hairs or threads inside socks or under bed sheets can become spontaneously tied round a toe and tighten with the child's movement → venous and lymphatic return is impaired → further obstruction may cause arterial occlusion and ischemic injury
  • Clinical features: painful, swollen, reddened appendage with a deep groove proximal to it, in which the constricting fiber may be visible
  • Treatment: prompt removal of the constricting hair or fiber, either by means of a hair-dissolving product or a scalpel

Drug-induced vasoconstriction


Stagestoggle arrow icon

The severity of ALI is assessed through physical examination and Doppler studies. Affected limbs can range from viable to nonviable (irreversible ischemia).

Sensory loss Muscle weakness Pain Hand-held Doppler signal
Arterial Venous
Viable None None Mild to moderate Audible flow Audible flow
Threatened Minimal Mild to moderate Severe No flow Audible flow
Nonviable Anesthetic limb Paralysis None No flow No flow


Diagnosticstoggle arrow icon


Treatmenttoggle arrow icon

Complicationstoggle arrow icon

We list the most important complications. The selection is not exhaustive.

Referencestoggle arrow icon

  1. Smith DA, Lilie CJ. Arterial Occlusion, Acute. Stat pearls. 2019.
  2. Callum K. ABC of arterial and venous disease: Acute limb ischaemia. BMJ. 2000; 320 (7237): p.764-767.doi: 10.1136/bmj.320.7237.764 . | Open in Read by QxMD
  3. Howard DP, Banerjee A, Fairhead JF, et al. Population-Based Study of Incidence, Risk Factors, Outcome, and Prognosis of Ischemic Peripheral Arterial Events: Implications for Prevention.. Circulation. 2015; 132 (19): p.1805-15.doi: 10.1161/CIRCULATIONAHA.115.016424 . | Open in Read by QxMD
  4. Mitchell ME, Carpenter JP. Overview of acute arterial occlusion of the extremities (acute limb ischemia). In: Post TW, ed. UpToDate. Waltham, MA: UpToDate. Last updated: May 31, 2016. Accessed: December 13, 2016.
  5. Stephens E. Peripheral Vascular Disease. In: Schraga ED, Peripheral Vascular Disease. New York, NY: WebMD. Updated: December 13, 2016. Accessed: November 7, 2017.

Icon of a lock3 free articles remaining

You have 3 free member-only articles left this month. Sign up and get unlimited access.
 Evidence-based content, created and peer-reviewed by physicians. Read the disclaimer