Snapshot A 61-year-old man presents to the emergency department for severe right lower extremity pain. He has a medical history of hypertension, hyperlipidemia, coronary artery disease requiring drug-eluting stents, and type 2 diabetes mellitus. Physical examination is remarkable for a pale right lower extremity, significant weakness and sensory impairment, and absent capillary refill. Arterial Dopplers do not reveal an audible pulse. Vascular surgery was consulted for emergent amputation. Introduction Overview acute limb ischemic results from impaired blood perfusion to the affected limb arterial occlusion, rather than venous occlusion, most commonly leads to acute limb ischemia results in the 6 Ps pain pallor paresthesia pulselessness poikilothermia paralysis/paresthesia categories of acute limb ischemia viable or marginally threatened pain mild sensory and motor deficits none capillary refill normal arterial Doppler audible immediately threated pain severe sensory and motor deficits mild capillary refill delayed arterial Doppler absent irreversibly ischemic pain variable sensory and motor deficits severe or complete capillary refill absent arterial Doppler absent Epidemiology risk factors hypertension hyperlipidemia diabetes smoking peripheral artery disease Etiology atherosclerotic plaque may result from progressively occluding atherosclerotic plaque or Intraplaque hemorrhage and local hypercoagulability artery aneurysm artery dissection thrombophilia traumatic or iatrogenic arterial injury complication of vascular reconstruction (e.g., bypass graft) arterial or paradoxical embolism left ventricular aneurysm after myocardial infarction Associated conditions peripheral artery disease compartment syndrome Prognosis improved outcomes with immediate systemic anticoagulation and clot removal Presentation Symptoms/physical examination 6 Ps pain pallor paresthesia pulselessness poikilothermia paralysis/paresthesia Imaging CT angiography or catheter-based arteriography indication in patients with a viable ischemic limb Transthoracic echocardiogram can be used to confirm cardiac source of systemic embolism indication abrupt occlusion of major peripheral or visceral artery high suspicion of left ventricular thrombus Studies This is a clinical diagnosis that can be supported by imaging Differential Chronic limb ischemia differentiating factor symptoms present for >2 weeks Phlegmasia differentiating factor lower extremity edema limb cyanosis Treatment Medical systemic anti-coagulation (e.g., unfractionaed heparin) indication in all patients with acute limb ischemic intra-arterial rtPA indication in patients with viable limb ischemia Operative embolectomy indication in immediately threatened limb ischemia amputation indication in irreversible limb ischemia Complications Acute renal failure Hyperkalemia Infection