Acute Limb Ischemia (Clinical)

Overview

Definition^{[1, 4–7]}

Acute limb ischemia Ischemia A hypoperfusion of the blood through an organ or tissue caused by a pathologic constriction or obstruction of its blood vessels, or an absence of blood circulation. Ischemic Cell Damage (ALI) is a vascular emergency Vascular Emergency Acute Limb Ischemia caused by a rapid decrease in limb perfusion. Symptom duration is < 2 weeks following the acute event.

Epidemiology^[5]

• Incidence Incidence The number of new cases of a given disease during a given period in a specified population. It also is used for the rate at which new events occur in a defined population. It is differentiated from prevalence, which refers to all cases in the population at a given time. Measures of Disease Frequency: 1.5 cases per 10,000 people per year
• Frequency: men = women
• More common in the elderly
• The lower limb is affected in 80% of cases.

Etiology^[4]

• Arterial occlusion (most common):
  • Thrombosis Thrombosis Formation and development of a thrombus or blood clot in the blood vessel. Epidemic Typhus:
    • Thrombosed atherosclerotic artery
    • Thrombosed bypass graft Graft A piece of living tissue that is surgically transplanted Organ Transplantation 
    • Thrombosed popliteal artery Popliteal Artery The continuation of the femoral artery coursing through the popliteal fossa; it divides into the anterior and posterior tibial arteries. Popliteal Fossa: Anatomy aneurysm Aneurysm An aneurysm is a bulging, weakened area of a blood vessel that causes an abnormal widening of its diameter > 1.5 times the size of the native vessel. Aneurysms occur more often in arteries than in veins and are at risk of dissection and rupture, which can be life-threatening. Thoracic Aortic Aneurysms
    • Popliteal adventitial cyst Popliteal Adventitial Cyst Acute Limb Ischemia 
    • Hypercoagulable Hypercoagulable Hypercoagulable states (also referred to as thrombophilias) are a group of hematologic diseases defined by an increased risk of clot formation (i.e., thrombosis) due to either an increase in procoagulants, a decrease in anticoagulants, or a decrease in fibrinolysis. Hypercoagulable States states (e.g., antiphospholipid antibody syndrome, heparin-induced thrombocytopenia Heparin-Induced Thrombocytopenia Thrombocytopenia) 
  • Embolism:
    • Thromboembolism Thromboembolism Obstruction of a blood vessel (embolism) by a blood clot (thrombus) in the blood stream. Systemic Lupus Erythematosus (due to arrhythmias and/or sequelae of MI MI MI is ischemia and death of an area of myocardial tissue due to insufficient blood flow and oxygenation, usually from thrombus formation on a ruptured atherosclerotic plaque in the epicardial arteries. Clinical presentation is most commonly with chest pain, but women and patients with diabetes may have atypical symptoms. Myocardial Infarction)
    • Atheroembolism Atheroembolism An embolus is an intravascular solid, liquid, or gaseous material that is carried by the blood to a site distant from its point of origin. Emboli of all types warrant immediate medical attention. The majority of emboli dislodge from a thrombus, forming a thromboembolus. Other less common nonthrombotic types of emboli are cholesterol, fat, air, amniotic fluid, and tumor emboli. Nonthrombotic Embolism ( cholesterol Cholesterol The principal sterol of all higher animals, distributed in body tissues, especially the brain and spinal cord, and in animal fats and oils. Cholesterol Metabolism emboli)
    • Paradoxical emboli
    • Septic emboli
  • Arterial dissection Arterial dissection Arterial dissection is a violation of the structural integrity of the arterial wall that results in blood accumulating between the layers. Dissection of the Carotid and Vertebral Arteries
  • Trauma:
    • Iatrogenic Iatrogenic Any adverse condition in a patient occurring as the result of treatment by a physician, surgeon, or other health professional, especially infections acquired by a patient during the course of treatment. Anterior Cord Syndrome injury
    • Injuries of the lower extremities (e.g., posterior knee dislocations)
• Venous occlusion: phlegmasia cerulea dolens Phlegmasia cerulea dolens Near-total occlusion of the deep venous system resulting in venous gangrene. Acute Limb Ischemia (near-total occlusion of the deep venous system resulting in venous gangrene Gangrene Death and putrefaction of tissue usually due to a loss of blood supply. Small Bowel Obstruction)^[2]
• Other:
  • Ergotism
  • Vasopressor Vasopressor Acute Cholangitis medications
  • HIV HIV Anti-HIV Drugs arteriopathy
  • Vasculitis Vasculitis Inflammation of any one of the blood vessels, including the arteries; veins; and rest of the vasculature system in the body. Systemic Lupus Erythematosus
  • Compartment syndrome Compartment Syndrome Compartment syndrome is a surgical emergency usually occurring secondary to trauma. The condition is marked by increased pressure within a compartment that compromises the circulation and function of the tissues within that space. Compartment Syndrome
  • Low-flow states:
    • Heart failure Heart Failure A heterogeneous condition in which the heart is unable to pump out sufficient blood to meet the metabolic need of the body. Heart failure can be caused by structural defects, functional abnormalities (ventricular dysfunction), or a sudden overload beyond its capacity. Chronic heart failure is more common than acute heart failure which results from sudden insult to cardiac function, such as myocardial infarction. Total Anomalous Pulmonary Venous Return (TAPVR)
    • Hypovolemia Hypovolemia Sepsis in Children
    • Hypotension Hypotension Hypotension is defined as low blood pressure, specifically < 90/60 mm Hg, and is most commonly a physiologic response. Hypotension may be mild, serious, or life threatening, depending on the cause. Hypotension

Pathophysiology

• Common locations of vessel occlusion:^[10]
  • Thrombi:
    • Femoral artery Femoral Artery The main artery of the thigh, a continuation of the external iliac artery. Femoral Region and Hernias: Anatomy
    • Popliteal artery Popliteal Artery The continuation of the femoral artery coursing through the popliteal fossa; it divides into the anterior and posterior tibial arteries. Popliteal Fossa: Anatomy
  • Emboli:
    • Aortic bifurcation
    • Iliac bifurcation
    • Femoral bifurcation
    • Popliteal bifurcation
• Risk factors:^[5]
  • Smoking Smoking Willful or deliberate act of inhaling and exhaling smoke from burning substances or agents held by hand. Interstitial Lung Diseases
  • Diabetes Diabetes Diabetes mellitus (DM) is a metabolic disease characterized by hyperglycemia and dysfunction of the regulation of glucose metabolism by insulin. Type 1 DM is diagnosed mostly in children and young adults as the result of autoimmune destruction of β cells in the pancreas and the resulting lack of insulin. Type 2 DM has a significant association with obesity and is characterized by insulin resistance. Diabetes Mellitus mellitus
  • Obesity Obesity Obesity is a condition associated with excess body weight, specifically with the deposition of excessive adipose tissue. Obesity is considered a global epidemic. Major influences come from the western diet and sedentary lifestyles, but the exact mechanisms likely include a mixture of genetic and environmental factors. Obesity
  • Arterial hypertension Hypertension Hypertension, or high blood pressure, is a common disease that manifests as elevated systemic arterial pressures. Hypertension is most often asymptomatic and is found incidentally as part of a routine physical examination or during triage for an unrelated medical encounter. Hypertension
  • High cholesterol Cholesterol The principal sterol of all higher animals, distributed in body tissues, especially the brain and spinal cord, and in animal fats and oils. Cholesterol Metabolism
  • Sedentary lifestyle
  • Family history Family History Adult Health Maintenance of vascular disease
• Pathogenesis of ALI:^[10]
  • The initiating event of reduced perfusion leads to a switch to anaerobic metabolism.
  • Lactate production and acidosis Acidosis A pathologic condition of acid accumulation or depletion of base in the body. The two main types are respiratory acidosis and metabolic acidosis, due to metabolic acid build up. Respiratory Acidosis 
  • Depletion of ATP stores
  • Dysfunction of Na⁺/K⁺-ATPase pump Pump ACES and RUSH: Resuscitation Ultrasound Protocols and sodium Sodium A member of the alkali group of metals. It has the atomic symbol na, atomic number 11, and atomic weight 23. Hyponatremia/ calcium Calcium A basic element found in nearly all tissues. It is a member of the alkaline earth family of metals with the atomic symbol ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes. Electrolytes pump Pump ACES and RUSH: Resuscitation Ultrasound Protocols
  • Leakage of calcium Calcium A basic element found in nearly all tissues. It is a member of the alkaline earth family of metals with the atomic symbol ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes. Electrolytes into myocytes Myocytes Mature contractile cells, commonly known as myocytes, that form one of three kinds of muscle. The three types of muscle cells are skeletal, cardiac, and smooth. They are derived from embryonic (precursor) muscle cells called myoblasts. Muscle Tissue: Histology
  • Dysfunction of actin Actin Filamentous proteins that are the main constituent of the thin filaments of muscle fibers. The filaments (known also as filamentous or f-actin) can be dissociated into their globular subunits; each subunit is composed of a single polypeptide 375 amino acids long. This is known as globular or g-actin. In conjunction with myosins, actin is responsible for the contraction and relaxation of muscle. Skeletal Muscle Contraction, myosin Myosin A diverse superfamily of proteins that function as translocating proteins. They share the common characteristics of being able to bind actins and hydrolyze mgATP. Myosins generally consist of heavy chains which are involved in locomotion, and light chains which are involved in regulation. Within the structure of myosin heavy chain are three domains: the head, the neck and the tail. The head region of the heavy chain contains the actin binding domain and mgATPase domain which provides energy for locomotion. The neck region is involved in binding the light-chains. The tail region provides the anchoring point that maintains the position of the heavy chain. The superfamily of myosins is organized into structural classes based upon the type and arrangement of the subunits they contain. Skeletal Muscle Contraction, proteases Proteases Proteins and Peptides 
  • Development of muscle necrosis Muscle Necrosis Rhabdomyolysis

Clinical Presentation

Features^[1,4–7,14]

• Occlusive arterial embolism presents with sudden onset of severe pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways.
• Venous thrombosis Venous thrombosis The formation or presence of a blood clot (thrombus) within a vein. Budd-Chiari Syndrome is more indolent.
• The 6 Ps PS Invasive Mechanical Ventilation of acute peripheral vessel occlusion :
  • Pain:
    • Sudden onset and constant
    • Worsens with passive movement
  • Pallor:
    • Seen in early stages
    • Later progresses to cyanosis Cyanosis A bluish or purplish discoloration of the skin and mucous membranes due to an increase in the amount of deoxygenated hemoglobin in the blood or a structural defect in the hemoglobin molecule. Pulmonary Examination
  • Poikilothermia (cold to the touch)
  • Paralysis
  • Paresthesia
    • The longer ischemia Ischemia A hypoperfusion of the blood through an organ or tissue caused by a pathologic constriction or obstruction of its blood vessels, or an absence of blood circulation. Ischemic Cell Damage is present, the greater the chance that pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways will turn into paresthesia/ sensory Sensory Neurons which conduct nerve impulses to the central nervous system. Nervous System: Histology loss.
  • Pulselessness
  • All 6 signs are rarely seen at the same time.

Diagnosis

Acute limb ischemia Ischemia A hypoperfusion of the blood through an organ or tissue caused by a pathologic constriction or obstruction of its blood vessels, or an absence of blood circulation. Ischemic Cell Damage is diagnosed on the basis of medical history, clinical presentation, physical examination, and vascular imaging.^[1,5]

History

• Symptoms related to pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways:
  • Onset
  • Location
  • Intensity
  • Presence of motor Motor Neurons which send impulses peripherally to activate muscles or secretory cells. Nervous System: Histology and sensory Sensory Neurons which conduct nerve impulses to the central nervous system. Nervous System: Histology changes
• Background information:
  • Recent interventions
  • Trauma
  • Presence or a family history Family History Adult Health Maintenance of cardiovascular disease
  • Medications
• Risk factors

Physical exam^[7,10]

Assess for the 6 Ps PS Invasive Mechanical Ventilation:

• Pain:
  • Usually noted distally in the initial phase Initial Phase Sepsis in Children of ischemia Ischemia A hypoperfusion of the blood through an organ or tissue caused by a pathologic constriction or obstruction of its blood vessels, or an absence of blood circulation. Ischemic Cell Damage
  • Pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways increases in intensity and becomes proximal with longer ischemic duration.
• Pallor
  • Check color and capillary refill of both the affected and the normal extremities.
  • Reduced perfusion: pale or mottled skin Skin The skin, also referred to as the integumentary system, is the largest organ of the body. The skin is primarily composed of the epidermis (outer layer) and dermis (deep layer). The epidermis is primarily composed of keratinocytes that undergo rapid turnover, while the dermis contains dense layers of connective tissue. Skin: Structure and Functions
• Poikilothermia
  • Check skin Skin The skin, also referred to as the integumentary system, is the largest organ of the body. The skin is primarily composed of the epidermis (outer layer) and dermis (deep layer). The epidermis is primarily composed of keratinocytes that undergo rapid turnover, while the dermis contains dense layers of connective tissue. Skin: Structure and Functions temperature of both the affected and the normal extremities.
  • Reduced perfusion: cooler skin Skin The skin, also referred to as the integumentary system, is the largest organ of the body. The skin is primarily composed of the epidermis (outer layer) and dermis (deep layer). The epidermis is primarily composed of keratinocytes that undergo rapid turnover, while the dermis contains dense layers of connective tissue. Skin: Structure and Functions than the normal extremity
• Paralysis:
  • Check motor Motor Neurons which send impulses peripherally to activate muscles or secretory cells. Nervous System: Histology function/strength.
  • Muscle weakness is noted in the final stages of injury from ischemia Ischemia A hypoperfusion of the blood through an organ or tissue caused by a pathologic constriction or obstruction of its blood vessels, or an absence of blood circulation. Ischemic Cell Damage.
  • Foot drop Foot Drop Leprosy: frequently the 1st symptom of motor Motor Neurons which send impulses peripherally to activate muscles or secretory cells. Nervous System: Histology paralysis^[1]
  • A poor prognostic sign
• Paresthesia:
  • Check for sensory Sensory Neurons which conduct nerve impulses to the central nervous system. Nervous System: Histology deficits.
  • Sensory Sensory Neurons which conduct nerve impulses to the central nervous system. Nervous System: Histology loss is a sign of progressive ischemia Ischemia A hypoperfusion of the blood through an organ or tissue caused by a pathologic constriction or obstruction of its blood vessels, or an absence of blood circulation. Ischemic Cell Damage.
• Pulselessness:
  • Palpation Palpation Application of fingers with light pressure to the surface of the body to determine consistency of parts beneath in physical diagnosis; includes palpation for determining the outlines of organs. Dermatologic Examination of the popliteal, femoral, dorsal artery of the foot Foot The foot is the terminal portion of the lower limb, whose primary function is to bear weight and facilitate locomotion. The foot comprises 26 bones, including the tarsal bones, metatarsal bones, and phalanges. The bones of the foot form longitudinal and transverse arches and are supported by various muscles, ligaments, and tendons. Foot: Anatomy, and posterior tibial arteries Arteries Arteries are tubular collections of cells that transport oxygenated blood and nutrients from the heart to the tissues of the body. The blood passes through the arteries in order of decreasing luminal diameter, starting in the largest artery (the aorta) and ending in the small arterioles. Arteries are classified into 3 types: large elastic arteries, medium muscular arteries, and small arteries and arterioles. Arteries: Histology
  • Use handheld Doppler Doppler Ultrasonography applying the doppler effect, with frequency-shifted ultrasound reflections produced by moving targets (usually red blood cells) in the bloodstream along the ultrasound axis in direct proportion to the velocity of movement of the targets, to determine both direction and velocity of blood flow. Ultrasound (Sonography) to confirm pulses.
  • Ankle-brachial index Ankle-brachial index Comparison of the blood pressure between the brachial artery and the posterior tibial artery. It is a predictor of peripheral arterial disease. Cardiovascular Examination (ABI) bilaterally:^[7]
    • ABI: ratio of the higher ankle systolic pressure (posterior tibial or dorsalis pedis) and the higher arm Arm The arm, or “upper arm” in common usage, is the region of the upper limb that extends from the shoulder to the elbow joint and connects inferiorly to the forearm through the cubital fossa. It is divided into 2 fascial compartments (anterior and posterior). Arm: Anatomy systolic pressure (left or right) 
    • An abnormal ABI ≤ 0.90 (normal: 1–1.40, borderline: 0.91–0.99) indicates a hemodynamically significant occlusive arterial disease. 
    • ALI requires immediate vascular imaging, so ABI is not used in urgent settings.
    • Use ABI in those with suspected peripheral arterial disease.
    • Not accurate in noncompressible arteries Arteries Arteries are tubular collections of cells that transport oxygenated blood and nutrients from the heart to the tissues of the body. The blood passes through the arteries in order of decreasing luminal diameter, starting in the largest artery (the aorta) and ending in the small arterioles. Arteries are classified into 3 types: large elastic arteries, medium muscular arteries, and small arteries and arterioles. Arteries: Histology (use toe-brachial index)

Other possible findings:

• Nonhealing lower-extremity wound
• Lower-extremity gangrene Gangrene Death and putrefaction of tissue usually due to a loss of blood supply. Small Bowel Obstruction
• Blistering (a sign of advanced ischemia Ischemia A hypoperfusion of the blood through an organ or tissue caused by a pathologic constriction or obstruction of its blood vessels, or an absence of blood circulation. Ischemic Cell Damage)
• Skin Skin The skin, also referred to as the integumentary system, is the largest organ of the body. The skin is primarily composed of the epidermis (outer layer) and dermis (deep layer). The epidermis is primarily composed of keratinocytes that undergo rapid turnover, while the dermis contains dense layers of connective tissue. Skin: Structure and Functions atrophy Atrophy Decrease in the size of a cell, tissue, organ, or multiple organs, associated with a variety of pathological conditions such as abnormal cellular changes, ischemia, malnutrition, or hormonal changes. Cellular Adaptation
• Hair loss in affected area

Diagnostic testing

Clinical assessment:

• ALI is a surgical emergency Surgical Emergency Acute Abdomen.^[7]
• Consult vascular surgery Vascular surgery Vascular surgery is the specialized field of medicine that focuses on the surgical management of the pathologies of the peripheral circulation. The main goal of most vascular procedures is to restore circulatory function to the affected vessels by relieving occlusions or by redirecting blood flow (e.g., bypass). Vascular Surgery immediately.
• All causes of ALI, either embolic or thrombotic, can be worked up after revascularization Revascularization Thromboangiitis Obliterans (Buerger’s Disease).
• Immediate diagnostic steps:
  • Obtain the following:
    • Symptom onset (important, as this affects the revascularization Revascularization Thromboangiitis Obliterans (Buerger’s Disease) strategy; e.g., catheter-directed therapy is most effective if onset < 2 weeks)
    • Pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways intensity
    • Presence of sensory Sensory Neurons which conduct nerve impulses to the central nervous system. Nervous System: Histology and/or motor Motor Neurons which send impulses peripherally to activate muscles or secretory cells. Nervous System: Histology deficits
  • Bedside assessment with continuous-wave Doppler Continuous-Wave Doppler Ultrasound (Sonography) (checking both venous and arterial signals)
  • Classify ALI (Rutherford classification).
  • Proceed with urgent imaging.
• Categories of ischemia Ischemia A hypoperfusion of the blood through an organ or tissue caused by a pathologic constriction or obstruction of its blood vessels, or an absence of blood circulation. Ischemic Cell Damage are based on clinical signs and Doppler Doppler Ultrasonography applying the doppler effect, with frequency-shifted ultrasound reflections produced by moving targets (usually red blood cells) in the bloodstream along the ultrasound axis in direct proportion to the velocity of movement of the targets, to determine both direction and velocity of blood flow. Ultrasound (Sonography) results:^[6,7]
  • Viable limb Viable limb Absence of pain at rest, sensory loss, and/or muscle weakness, arterial and venous flows are present. Acute Limb Ischemia (I):
    • Absence of pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways at rest, sensory Sensory Neurons which conduct nerve impulses to the central nervous system. Nervous System: Histology loss, and/or muscle weakness
    • Arterial and venous flows are present.
    • Audible Doppler Doppler Ultrasonography applying the doppler effect, with frequency-shifted ultrasound reflections produced by moving targets (usually red blood cells) in the bloodstream along the ultrasound axis in direct proportion to the velocity of movement of the targets, to determine both direction and velocity of blood flow. Ultrasound (Sonography) signals
    • Allows time for vascular imaging to determine extent of disease
  • Marginally threatened limb Threatened limb Minimal sensory loss, mild-to-moderate muscle weakness, absent arterial doppler tones, requires urgent intervention. Acute Limb Ischemia (IIa):
    • Minimal pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways
    • Minimal to no sensory Sensory Neurons which conduct nerve impulses to the central nervous system. Nervous System: Histology loss
    • No muscle weakness
    • Inaudible arterial Doppler Doppler Ultrasonography applying the doppler effect, with frequency-shifted ultrasound reflections produced by moving targets (usually red blood cells) in the bloodstream along the ultrasound axis in direct proportion to the velocity of movement of the targets, to determine both direction and velocity of blood flow. Ultrasound (Sonography) signals but audible venous Doppler Doppler Ultrasonography applying the doppler effect, with frequency-shifted ultrasound reflections produced by moving targets (usually red blood cells) in the bloodstream along the ultrasound axis in direct proportion to the velocity of movement of the targets, to determine both direction and velocity of blood flow. Ultrasound (Sonography) signals
    • Can be salvaged if treatment is initiated promptly
  • Immediately threatened limb Threatened limb Minimal sensory loss, mild-to-moderate muscle weakness, absent arterial doppler tones, requires urgent intervention. Acute Limb Ischemia (IIb):
    • Minimal sensory Sensory Neurons which conduct nerve impulses to the central nervous system. Nervous System: Histology loss
    • Mild-to-moderate muscle weakness
    • Absent arterial Doppler Doppler Ultrasonography applying the doppler effect, with frequency-shifted ultrasound reflections produced by moving targets (usually red blood cells) in the bloodstream along the ultrasound axis in direct proportion to the velocity of movement of the targets, to determine both direction and velocity of blood flow. Ultrasound (Sonography) tones
    • Requires urgent intervention
  • Irreversible ischemic damage (III):
    • Sensory Sensory Neurons which conduct nerve impulses to the central nervous system. Nervous System: Histology loss, paralysis, and/or permanent nerve damage
    • Absent arterial and venous Doppler Doppler Ultrasonography applying the doppler effect, with frequency-shifted ultrasound reflections produced by moving targets (usually red blood cells) in the bloodstream along the ultrasound axis in direct proportion to the velocity of movement of the targets, to determine both direction and velocity of blood flow. Ultrasound (Sonography) tones
    • Revascularization Revascularization Thromboangiitis Obliterans (Buerger’s Disease) may result in rhabdomyolysis Rhabdomyolysis Rhabdomyolysis is characterized by muscle necrosis and the release of toxic intracellular contents, especially myoglobin, into the circulation. Rhabdomyolysis and AKI AKI Acute kidney injury refers to sudden and often reversible loss of renal function, which develops over days or weeks. Azotemia refers to elevated levels of nitrogen-containing substances in the blood that accompany AKI, which include BUN and creatinine. Acute Kidney Injury.

Anatomic assessment and additional studies:^[6,7]

• Vascular imaging:
  • Helps determine anatomic location and severity of occlusion
  • Choice of imaging is affected by the urgency of revascularization Revascularization Thromboangiitis Obliterans (Buerger’s Disease) and the time needed to obtain images.
  • Doppler Doppler Ultrasonography applying the doppler effect, with frequency-shifted ultrasound reflections produced by moving targets (usually red blood cells) in the bloodstream along the ultrasound axis in direct proportion to the velocity of movement of the targets, to determine both direction and velocity of blood flow. Ultrasound (Sonography) ultrasonography shows the absence of blood flow Blood flow Blood flow refers to the movement of a certain volume of blood through the vasculature over a given unit of time (e.g., mL per minute). Vascular Resistance, Flow, and Mean Arterial Pressure distal to the site of occlusion.
  • Confirmatory imaging:
    • Digital subtraction angiography Angiography Radiography of blood vessels after injection of a contrast medium. Cardiac Surgery (DSA), CTA CTA A non-invasive method that uses a ct scanner for capturing images of blood vessels and tissues. A contrast material is injected, which helps produce detailed images that aid in diagnosing vascular diseases. Pulmonary Function Tests, or MRA MRA Imaging of the Heart and Great Vessels
    • Perform in viable and marginally threatened limb Threatened limb Minimal sensory loss, mild-to-moderate muscle weakness, absent arterial doppler tones, requires urgent intervention. Acute Limb Ischemia ischemia Ischemia A hypoperfusion of the blood through an organ or tissue caused by a pathologic constriction or obstruction of its blood vessels, or an absence of blood circulation. Ischemic Cell Damage.
    • It is preferable to evaluate immediately threatened limb Threatened limb Minimal sensory loss, mild-to-moderate muscle weakness, absent arterial doppler tones, requires urgent intervention. Acute Limb Ischemia ischemia Ischemia A hypoperfusion of the blood through an organ or tissue caused by a pathologic constriction or obstruction of its blood vessels, or an absence of blood circulation. Ischemic Cell Damage with angiography Angiography Radiography of blood vessels after injection of a contrast medium. Cardiac Surgery in a vascular surgery Vascular surgery Vascular surgery is the specialized field of medicine that focuses on the surgical management of the pathologies of the peripheral circulation. The main goal of most vascular procedures is to restore circulatory function to the affected vessels by relieving occlusions or by redirecting blood flow (e.g., bypass). Vascular Surgery suite.
    • Usually, vascular imaging is not needed in a nonviable limb (class III).
• DSA has the advantage of providing the diagnosis and offering therapeutic options.^[7,15]
  • Findings in thrombotic occlusion:
    • Areas with atherosclerosis Atherosclerosis Atherosclerosis is a common form of arterial disease in which lipid deposition forms a plaque in the blood vessel walls. Atherosclerosis is an incurable disease, for which there are clearly defined risk factors that often can be reduced through a change in lifestyle and behavior of the patient. Atherosclerosis 
    • Collateral vessels (seen more in chronic thrombosis Thrombosis Formation and development of a thrombus or blood clot in the blood vessel. Epidemic Typhus)
  • Findings in embolic occlusion:
    • Generally intact vasculature with acute cutoff
    • “Meniscus sign” (crescent-shaped occlusion), with the rest of the vessels appearing normal
• Supporting studies:^[13]
  • ECG ECG An electrocardiogram (ECG) is a graphic representation of the electrical activity of the heart plotted against time. Adhesive electrodes are affixed to the skin surface allowing measurement of cardiac impulses from many angles. The ECG provides 3-dimensional information about the conduction system of the heart, the myocardium, and other cardiac structures. Electrocardiogram (ECG)
  • Echocardiography Echocardiography Ultrasonic recording of the size, motion, and composition of the heart and surrounding tissues. The standard approach is transthoracic. Tricuspid Valve Atresia (TVA)
  • Duplex ultrasound of the aorta Aorta The main trunk of the systemic arteries. Mediastinum and Great Vessels: Anatomy (in those with suspected abdominal aortic aneurysm Aortic aneurysm An abnormal balloon- or sac-like dilatation in the wall of aorta. Thoracic Aortic Aneurysms)
  • CBC
  • Blood chemistry
  • Coagulation studies Coagulation studies Coagulation studies are a group of hematologic laboratory studies that reflect the function of blood vessels, platelets, and coagulation factors, which all interact with one another to achieve hemostasis. Coagulation studies are usually ordered to evaluate patients with bleeding or hypercoagulation disorders. Coagulation Studies (including proteins Proteins Linear polypeptides that are synthesized on ribosomes and may be further modified, crosslinked, cleaved, or assembled into complex proteins with several subunits. The specific sequence of amino acids determines the shape the polypeptide will take, during protein folding, and the function of the protein. Energy Homeostasis C and S, anticardiolipin antibodies Anticardiolipin antibodies Antiphospholipid antibodies found in association with systemic lupus erythematosus, antiphospholipid syndrome; and in a variety of other diseases as well as in healthy individuals. The antibodies are detected by solid-phase immunoassay employing the purified phospholipid antigen cardiolipin. Antiphospholipid Syndrome, and antithrombin Antithrombin Endogenous factors and drugs that directly inhibit the action of thrombin, usually by blocking its enzymatic activity. They are distinguished from indirect thrombin inhibitors, such as heparin, which act by enhancing the inhibitory effects of antithrombins. Anticoagulants III for thrombophilia Thrombophilia A disorder of hemostasis in which there is a tendency for the occurrence of thrombosis. Hypercoagulable States screening Screening Preoperative Care)
  • Creatine Creatine An amino acid that occurs in vertebrate tissues and in urine. In muscle tissue, creatine generally occurs as phosphocreatine. Creatine is excreted as creatinine in the urine. Acute Kidney Injury kinase and myoglobin Myoglobin A conjugated protein which is the oxygen-transporting pigment of muscle. It is made up of one globin polypeptide chain and one heme group. Rhabdomyolysis (markers for muscle damage)
  • Lactic acid

Management

Management can vary according to location. The following information is based on US and European medical society recommendations.

Immediate recognition of ALI^[6,7]

• Rapid assessment of limb viability and ability to restore blood flow Blood flow Blood flow refers to the movement of a certain volume of blood through the vasculature over a given unit of time (e.g., mL per minute). Vascular Resistance, Flow, and Mean Arterial Pressure are required:
  • The skeletal muscles Skeletal muscles A subtype of striated muscle, attached by tendons to the skeleton. Skeletal muscles are innervated and their movement can be consciously controlled. They are also called voluntary muscles. Muscle Tissue: Histology generally do not tolerate ischemia Ischemia A hypoperfusion of the blood through an organ or tissue caused by a pathologic constriction or obstruction of its blood vessels, or an absence of blood circulation. Ischemic Cell Damage for > 4–6 hours.
  • Longer periods (> 6–8 hours) lessen possibility of limb salvage.
• All ALI patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship should receive:^[14]
  • Prompt evaluation by vascular surgery Vascular surgery Vascular surgery is the specialized field of medicine that focuses on the surgical management of the pathologies of the peripheral circulation. The main goal of most vascular procedures is to restore circulatory function to the affected vessels by relieving occlusions or by redirecting blood flow (e.g., bypass). Vascular Surgery service 
  • Pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways control:
    • Morphine Morphine The principal alkaloid in opium and the prototype opiate analgesic and narcotic. Morphine has widespread effects in the central nervous system and on smooth muscle. Opioid Analgesics 2‒4 mg IV every 5‒15 minutes, titrated to effect^[8]
    • Fentanyl Fentanyl A potent narcotic analgesic, abuse of which leads to habituation or addiction. It is primarily a mu-opioid agonist. Fentanyl is also used as an adjunct to general anesthetics, and as an anesthetic for induction and maintenance. Opioid Analgesics 25‒50 µg IV every 2‒5 minutes, titrated to effect^[9]
  • IV hydration Iv Hydration Crush Syndrome^[6]
  • Supplement O₂^[6]

Treatment approach

The treatment approach depends on the severity or category of ischemic injury.

• Treatment starts with IV heparin infusion (unless contraindicated).^[6,7,13]
  • Heparin 60‒80 units/kg bolus IV (up to 100 units/kg according to the ESVS), then 12‒18 units/kg/hr of infusion^[1,12]
  • Titrate to institutional guidelines for activated partial thromboplastin time Partial thromboplastin time The time required for the appearance of fibrin strands following the mixing of plasma with phospholipid platelet substitute (e.g., crude cephalins, soybean phosphatides). It is a test of the intrinsic pathway (factors VIII, IX, XI, and XII) and the common pathway (fibrinogen, prothrombin, factors V and X) of blood coagulation. Hemostasis (aPTT).
  • Anticoagulation Anticoagulation Pulmonary Hypertension Drugs decreases the propagation Propagation Propagation refers to how the electrical signal spreads to every myocyte in the heart. Cardiac Physiology of thrombus and the risk of worsening ischemia Ischemia A hypoperfusion of the blood through an organ or tissue caused by a pathologic constriction or obstruction of its blood vessels, or an absence of blood circulation. Ischemic Cell Damage.
  • Consult hematology (for other options) if the patient has heparin-induced thrombocytopenia Heparin-Induced Thrombocytopenia Thrombocytopenia. 
• Categorize ALI according to the Rutherford classification, which helps determine:
  • Potential for limb salvage
  • Urgency of revascularization Revascularization Thromboangiitis Obliterans (Buerger’s Disease)
• Based on the severity of ALI, decide on revascularization Revascularization Thromboangiitis Obliterans (Buerger’s Disease):^[6,7,13]
  • Strategy depends on:
    • Availability and expertise
    • Patient factors ( comorbidities Comorbidities The presence of co-existing or additional diseases with reference to an initial diagnosis or with reference to the index condition that is the subject of study. Comorbidity may affect the ability of affected individuals to function and also their survival; it may be used as a prognostic indicator for length of hospital stay, cost factors, and outcome or survival. St. Louis Encephalitis Virus, etiology of ischemia Ischemia A hypoperfusion of the blood through an organ or tissue caused by a pathologic constriction or obstruction of its blood vessels, or an absence of blood circulation. Ischemic Cell Damage, contraindications Contraindications A condition or factor associated with a recipient that makes the use of a drug, procedure, or physical agent improper or inadvisable. Contraindications may be absolute (life threatening) or relative (higher risk of complications in which benefits may outweigh risks). Noninvasive Ventilation)
  • Choose the technique that would most rapidly restore blood flow Blood flow Blood flow refers to the movement of a certain volume of blood through the vasculature over a given unit of time (e.g., mL per minute). Vascular Resistance, Flow, and Mean Arterial Pressure, if medically suitable for the patient.
  • In case of trauma, surgery is often the choice.
  • If revascularization Revascularization Thromboangiitis Obliterans (Buerger’s Disease) is not possible in the facility, timely transfer to a capable center should be performed.
• Revascularization Revascularization Thromboangiitis Obliterans (Buerger’s Disease) strategies available:^[5–7,13]
  • Catheter-based (endovascular) revascularization Revascularization Thromboangiitis Obliterans (Buerger’s Disease) (which has lower mortality Mortality All deaths reported in a given population. Measures of Health Status compared to surgery):
    • Catheter-directed thrombolysis 
    • Percutaneous mechanical thrombectomy Thrombectomy Surgical removal of an obstructing clot or foreign material from a blood vessel at the point of its formation. Removal of a clot arising from a distant site is called embolectomy. Vascular Surgery
    • Percutaneous aspiration Percutaneous Aspiration Pyogenic Liver Abscess thrombectomy Thrombectomy Surgical removal of an obstructing clot or foreign material from a blood vessel at the point of its formation. Removal of a clot arising from a distant site is called embolectomy. Vascular Surgery
  • Surgery:
    • Open thromboembolectomy
    • Bypass surgery
  • Hybrid: combines the 2 strategies

Decision-making according to severity

• Irreversible ischemia Ischemia A hypoperfusion of the blood through an organ or tissue caused by a pathologic constriction or obstruction of its blood vessels, or an absence of blood circulation. Ischemic Cell Damage (class III): amputation Amputation An amputation is the separation of a portion of the limb or the entire limb from the body, along with the bone. Amputations are generally indicated for conditions that compromise the viability of the limb or promote the spread of a local process that could manifest systemically. Amputation^[5]
  • Permanent tissue loss and nerve damage are inevitable.
  • Prolonged ischemia Ischemia A hypoperfusion of the blood through an organ or tissue caused by a pathologic constriction or obstruction of its blood vessels, or an absence of blood circulation. Ischemic Cell Damage: most common factor in those requiring amputation Amputation An amputation is the separation of a portion of the limb or the entire limb from the body, along with the bone. Amputations are generally indicated for conditions that compromise the viability of the limb or promote the spread of a local process that could manifest systemically. Amputation
• Immediately threatened limb Threatened limb Minimal sensory loss, mild-to-moderate muscle weakness, absent arterial doppler tones, requires urgent intervention. Acute Limb Ischemia (class IIb)^[5]
  • Management: Revascularization Revascularization Thromboangiitis Obliterans (Buerger’s Disease) (endovascular or surgical) should be done within 6 hours (emergent).^[7]
  • Considerations in selecting treatment:
    • Immediate surgical revascularization Revascularization Thromboangiitis Obliterans (Buerger’s Disease) eliminates ischemia Ischemia A hypoperfusion of the blood through an organ or tissue caused by a pathologic constriction or obstruction of its blood vessels, or an absence of blood circulation. Ischemic Cell Damage promptly and thus is indicated in profound ischemia Ischemia A hypoperfusion of the blood through an organ or tissue caused by a pathologic constriction or obstruction of its blood vessels, or an absence of blood circulation. Ischemic Cell Damage.^[6,13]
    • Catheter-directed thrombolysis may also be used, if promptly initiated, but increased dosage Dosage Dosage Calculation or another endovascular technique may be needed.^[6]
• Marginally threatened limb Threatened limb Minimal sensory loss, mild-to-moderate muscle weakness, absent arterial doppler tones, requires urgent intervention. Acute Limb Ischemia (class IIa):^[1,6]
  • Management: revascularization Revascularization Thromboangiitis Obliterans (Buerger’s Disease) (endovascular or surgical) should be done within 6 hours (emergent).^[7]
  • Considerations in selecting treatment:
    • Class IIa ischemic injury generally has more time to spare than does class IIb.
    • Both endovascular and surgical options can be used; in a case where either produces similar short-term and long-term outcomes, endovascular therapy is preferred.^[5]

• Viable limb Viable limb Absence of pain at rest, sensory loss, and/or muscle weakness, arterial and venous flows are present. Acute Limb Ischemia (class I):
  • CTA CTA A non-invasive method that uses a ct scanner for capturing images of blood vessels and tissues. A contrast material is injected, which helps produce detailed images that aid in diagnosing vascular diseases. Pulmonary Function Tests/ MRA MRA Imaging of the Heart and Great Vessels to localize site of occlusion
  • Conservative treatment (European guidelines):^[6]
    • Goal-directed medical therapy and supervised walking therapy for claudication (see Peripheral Artery Disease Peripheral artery disease Peripheral artery disease (PAD) is obstruction of the arterial lumen resulting in decreased blood flow to the distal limbs. The disease can be a result of atherosclerosis or thrombosis. Patients may be asymptomatic or have progressive claudication, skin discoloration, ischemic ulcers, or gangrene. Peripheral Artery Disease section)
    • ESVS does not recommend percutaneous thrombolysis for acute-onset claudication.
    • Rationale: inconsistency in symptom relief and increased morbidity Morbidity The proportion of patients with a particular disease during a given year per given unit of population. Measures of Health Status with procedures (for a nonthreatened limb).
  • Revascularization Revascularization Thromboangiitis Obliterans (Buerger’s Disease): endovascular or surgical approach (US guidelines):
    • Should be done within 6–24 hours (urgent)^[7]
    • Like class IIa, class I severity allows time, so endovascular therapy (which has less morbidity Morbidity The proportion of patients with a particular disease during a given year per given unit of population. Measures of Health Status than surgery) is the initial therapy choice.^[13]
    • Ultimately, strategy is decided by the surgical team.^[5]

Follow-up^[7]

• All open and endovascular revascularization Revascularization Thromboangiitis Obliterans (Buerger’s Disease) procedures should have completion angiography Angiography Radiography of blood vessels after injection of a contrast medium. Cardiac Surgery, showing the outcome.^[6]
  • Residual thrombus is possible.
  • This helps to determine whether additional procedures are needed.
• Additional workup (if suspected cause is embolic):
  • ECG ECG An electrocardiogram (ECG) is a graphic representation of the electrical activity of the heart plotted against time. Adhesive electrodes are affixed to the skin surface allowing measurement of cardiac impulses from many angles. The ECG provides 3-dimensional information about the conduction system of the heart, the myocardium, and other cardiac structures. Electrocardiogram (ECG) or 24-hour ECG ECG An electrocardiogram (ECG) is a graphic representation of the electrical activity of the heart plotted against time. Adhesive electrodes are affixed to the skin surface allowing measurement of cardiac impulses from many angles. The ECG provides 3-dimensional information about the conduction system of the heart, the myocardium, and other cardiac structures. Electrocardiogram (ECG) monitoring if needed (arrhythmias)
  • Echocardiography Echocardiography Ultrasonic recording of the size, motion, and composition of the heart and surrounding tissues. The standard approach is transthoracic. Tricuspid Valve Atresia (TVA): suspected cardiac thrombus
  • Cardioembolic source warrants long-term anticoagulation Anticoagulation Pulmonary Hypertension Drugs.
  • Workup for hypercoagulable Hypercoagulable Hypercoagulable states (also referred to as thrombophilias) are a group of hematologic diseases defined by an increased risk of clot formation (i.e., thrombosis) due to either an increase in procoagulants, a decrease in anticoagulants, or a decrease in fibrinolysis. Hypercoagulable States disorders
• Risk factor modification for peripheral artery disease Peripheral artery disease Peripheral artery disease (PAD) is obstruction of the arterial lumen resulting in decreased blood flow to the distal limbs. The disease can be a result of atherosclerosis or thrombosis. Patients may be asymptomatic or have progressive claudication, skin discoloration, ischemic ulcers, or gangrene. Peripheral Artery Disease (PAD; see PAD section for management)^[6,7,13]
  • PAD is a coronary artery Coronary Artery Truncus Arteriosus disease equivalent.
  • Antiplatelet therapy or anticoagulation Anticoagulation Pulmonary Hypertension Drugs plus statins Statins Statins are competitive inhibitors of HMG-CoA reductase in the liver. HMG-CoA reductase is the rate-limiting step in cholesterol synthesis. Inhibition results in lowered intrahepatocytic cholesterol formation, resulting in up-regulation of LDL receptors and, ultimately, lowering levels of serum LDL and triglycerides. Statins is recommended to reduce cardiovascular events after revascularization Revascularization Thromboangiitis Obliterans (Buerger’s Disease).
  • Smoking Smoking Willful or deliberate act of inhaling and exhaling smoke from burning substances or agents held by hand. Interstitial Lung Diseases cessation
• Postprocedural visit:^[7,13]
  • Assess functional status.
  • Pulse examination and ABI measurements
  • Vascular imaging (if examination and/or ABI abnormalities are noted)
    • Doppler Doppler Ultrasonography applying the doppler effect, with frequency-shifted ultrasound reflections produced by moving targets (usually red blood cells) in the bloodstream along the ultrasound axis in direct proportion to the velocity of movement of the targets, to determine both direction and velocity of blood flow. Ultrasound (Sonography) US is preferred (noninvasive).
    • CTA CTA A non-invasive method that uses a ct scanner for capturing images of blood vessels and tissues. A contrast material is injected, which helps produce detailed images that aid in diagnosing vascular diseases. Pulmonary Function Tests or MRA-CE are alternatives.

Complications^[5–7]

• Bleeding:
  • Seen in 8%–10% of cases in which thrombolysis was used
  • Bleeding at arterial access site: most common
  • Interventions that can be applied:
    • Direct manual pressure
    • Repositioning of catheter 
    • Changing to larger sheath 
    • Stopping thrombolysis (especially if major bleeding occurs)
• Reperfusion injury Reperfusion injury Adverse functional, metabolic, or structural changes in ischemic tissues resulting from the restoration of blood flow to the tissue (reperfusion), including swelling; hemorrhage; necrosis; and damage from free radicals. The most common instance is myocardial reperfusion injury. Ischemic Cell Damage:
  • Production of highly reactive oxygen species Reactive oxygen species Molecules or ions formed by the incomplete one-electron reduction of oxygen. These reactive oxygen intermediates include singlet oxygen; superoxides; peroxides; hydroxyl radical; and hypochlorous acid. They contribute to the microbicidal activity of phagocytes, regulation of signal transduction and gene expression, and the oxidative damage to nucleic acids; proteins; and lipids. Nonalcoholic Fatty Liver Disease resulting in tissue injury
  • Acidosis Acidosis A pathologic condition of acid accumulation or depletion of base in the body. The two main types are respiratory acidosis and metabolic acidosis, due to metabolic acid build up. Respiratory Acidosis and hyperkalemia Hyperkalemia Hyperkalemia is defined as a serum potassium (K+) concentration >5.2 mEq/L. Homeostatic mechanisms maintain the serum K+ concentration between 3.5 and 5.2 mEq/L, despite marked variation in dietary intake. Hyperkalemia can be due to a variety of causes, which include transcellular shifts, tissue breakdown, inadequate renal excretion, and drugs. Hyperkalemia occur due to leakage from damaged cells.
  • Rhabdomyolysis Rhabdomyolysis Rhabdomyolysis is characterized by muscle necrosis and the release of toxic intracellular contents, especially myoglobin, into the circulation. Rhabdomyolysis
  • Cardiac arrhythmia
  • Acute tubular necrosis Necrosis The death of cells in an organ or tissue due to disease, injury or failure of the blood supply. Ischemic Cell Damage 
• Compartment syndrome Compartment Syndrome Compartment syndrome is a surgical emergency usually occurring secondary to trauma. The condition is marked by increased pressure within a compartment that compromises the circulation and function of the tissues within that space. Compartment Syndrome:
  • Increased capillary permeability leads to edema Edema Edema is a condition in which excess serous fluid accumulates in the body cavity or interstitial space of connective tissues. Edema is a symptom observed in several medical conditions. It can be categorized into 2 types, namely, peripheral (in the extremities) and internal (in an organ or body cavity). Edema and elevation of compartment pressure that results in circulatory collapse.
  • When compartment pressure exceeds 30 mm Hg, irreversible necrosis Necrosis The death of cells in an organ or tissue due to disease, injury or failure of the blood supply. Ischemic Cell Damage of nerve and muscle occurs.
  • Requires fasciotomy Fasciotomy Surgical incision on the fascia. It is used to decompress compartment pressure (e.g. in compartment syndromes; circumferential burns and extremity injuries) or to release contractures (e.g. in dupuytren’s contracture). Compartment Syndrome
• Chronic pain syndrome Chronic Pain Syndrome Fibromyalgia:
  • Prolonged ischemia Ischemia A hypoperfusion of the blood through an organ or tissue caused by a pathologic constriction or obstruction of its blood vessels, or an absence of blood circulation. Ischemic Cell Damage leads to permanent nerve damage, resulting in chronic pain Chronic pain Aching sensation that persists for more than a few months. It may or may not be associated with trauma or disease, and may persist after the initial injury has healed. Its localization, character, and timing are more vague than with acute pain. Pain Management.
  • Also known as ischemic neuropathy Neuropathy Leprosy

ALI in other clinical situations

• ALI of the upper extremity:^[6]
  • Majority of the cases are embolic in nature.
  • Diagnosis:
    • Palpation Palpation Application of fingers with light pressure to the surface of the body to determine consistency of parts beneath in physical diagnosis; includes palpation for determining the outlines of organs. Dermatologic Examination of pulses
    • Confirmation with Doppler Doppler Ultrasonography applying the doppler effect, with frequency-shifted ultrasound reflections produced by moving targets (usually red blood cells) in the bloodstream along the ultrasound axis in direct proportion to the velocity of movement of the targets, to determine both direction and velocity of blood flow. Ultrasound (Sonography) US or CTA CTA A non-invasive method that uses a ct scanner for capturing images of blood vessels and tissues. A contrast material is injected, which helps produce detailed images that aid in diagnosing vascular diseases. Pulmonary Function Tests
  • Anticoagulation Anticoagulation Pulmonary Hypertension Drugs alone can be considered up to class IIa.
  • Most patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship are treated with brachial embolectomy. 
  • Endovascular approach is an alternative but less common.
• ALI in children:^[6]
  • Rare, but can occur in:
    • Catheter-related arterial thrombosis Arterial Thrombosis Hypercoagulable States in neonates
    • Trauma (e.g., humerus Humerus Bone in humans and primates extending from the shoulder joint to the elbow joint. Arm: Anatomy fracture Fracture A fracture is a disruption of the cortex of any bone and periosteum and is commonly due to mechanical stress after an injury or accident. Open fractures due to trauma can be a medical emergency. Fractures are frequently associated with automobile accidents, workplace injuries, and trauma. Overview of Bone Fractures → brachial artery Brachial Artery The continuation of the axillary artery; it branches into the radial and ulnar arteries. Cubital Fossa: Anatomy injury)
    • Congenital Congenital Chorioretinitis heart disease or great vessel malformation
    • Coagulation disorders
    • Intrauterine compression Compression Blunt Chest Trauma
  • Manifests as cyanosis Cyanosis A bluish or purplish discoloration of the skin and mucous membranes due to an increase in the amount of deoxygenated hemoglobin in the blood or a structural defect in the hemoglobin molecule. Pulmonary Examination and poor capillary refill
  • Infants and children < 2 years of age: initial management with heparinization recommended
  • If conservative management fails, then thrombolysis or open surgical revascularization Revascularization Thromboangiitis Obliterans (Buerger’s Disease) may be considered.
  • In schoolchildren with supracondylar fracture Supracondylar fracture Supracondylar fractures are the most common elbow fractures in the pediatric population. The most common mechanism of injury involves a fall on an outstretched hand, resulting in a fracture of the distal humerus. Patients frequently present with pain, visible deformity, and limited range of motion of the injured elbow. Supracondylar Fracture of the humerus Humerus Bone in humans and primates extending from the shoulder joint to the elbow joint. Arm: Anatomy:
    • Watchful waiting is appropriate after closed reduction Closed Reduction Radial Head Subluxation (Nursemaid’s Elbow) and stabilization. 
    • Most resolve after fracture Fracture A fracture is a disruption of the cortex of any bone and periosteum and is commonly due to mechanical stress after an injury or accident. Open fractures due to trauma can be a medical emergency. Fractures are frequently associated with automobile accidents, workplace injuries, and trauma. Overview of Bone Fractures management.
    • Monitor hand Hand The hand constitutes the distal part of the upper limb and provides the fine, precise movements needed in activities of daily living. It consists of 5 metacarpal bones and 14 phalanges, as well as numerous muscles innervated by the median and ulnar nerves. Hand: Anatomy perfusion and pulses.

Differential Diagnosis

• Critical chronic limb ischemia Ischemia A hypoperfusion of the blood through an organ or tissue caused by a pathologic constriction or obstruction of its blood vessels, or an absence of blood circulation. Ischemic Cell Damage:  condition defined as > 2 weeks of chronic ischemic pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways in an extremity at rest plus ankle pressure < 50 mm Hg or toe pressure < 30 mm Hg. Patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship may present with claudication, resting pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways, hyperesthesia, dependent rubor Rubor Inflammation, and pallor during limb elevation. Untreated chronic limb ischemia Ischemia A hypoperfusion of the blood through an organ or tissue caused by a pathologic constriction or obstruction of its blood vessels, or an absence of blood circulation. Ischemic Cell Damage may progress to gangrene Gangrene Death and putrefaction of tissue usually due to a loss of blood supply. Small Bowel Obstruction. Diagnosis is made on the basis of history, physical examination, and findings of vascular imaging. Management is with revascularization Revascularization Thromboangiitis Obliterans (Buerger’s Disease). 
• Phlegmasia: rare complication of acute deep vein thrombosis Thrombosis Formation and development of a thrombus or blood clot in the blood vessel. Epidemic Typhus ( DVT DVT Deep vein thrombosis (DVT) usually occurs in the deep veins of the lower extremities. The affected veins include the femoral, popliteal, iliofemoral, and pelvic veins. Proximal DVT is more likely to cause a pulmonary embolism (PE) and is generally considered more serious. Deep Vein Thrombosis) characterized by increased venous pressure resulting in decreased tissue perfusion. Patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship present with extremity edema Edema Edema is a condition in which excess serous fluid accumulates in the body cavity or interstitial space of connective tissues. Edema is a symptom observed in several medical conditions. It can be categorized into 2 types, namely, peripheral (in the extremities) and internal (in an organ or body cavity). Edema, cyanosis Cyanosis A bluish or purplish discoloration of the skin and mucous membranes due to an increase in the amount of deoxygenated hemoglobin in the blood or a structural defect in the hemoglobin molecule. Pulmonary Examination, and severe pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways. The condition may progress to gangrene Gangrene Death and putrefaction of tissue usually due to a loss of blood supply. Small Bowel Obstruction. Diagnosis is made on the basis of clinical examination and Doppler Doppler Ultrasonography applying the doppler effect, with frequency-shifted ultrasound reflections produced by moving targets (usually red blood cells) in the bloodstream along the ultrasound axis in direct proportion to the velocity of movement of the targets, to determine both direction and velocity of blood flow. Ultrasound (Sonography) findings that show extensive thrombus in the deep venous system. Management is variable Variable Variables represent information about something that can change. The design of the measurement scales, or of the methods for obtaining information, will determine the data gathered and the characteristics of that data. As a result, a variable can be qualitative or quantitative, and may be further classified into subgroups. Types of Variables and includes conservative treatment, an endovascular approach, or surgery.
• Compartment syndrome Compartment Syndrome Compartment syndrome is a surgical emergency usually occurring secondary to trauma. The condition is marked by increased pressure within a compartment that compromises the circulation and function of the tissues within that space. Compartment Syndrome: emergency condition caused by increased intracompartmental pressure ( ICP ICP Normal intracranial pressure (ICP) is defined as < 15 mm Hg, whereas pathologically increased ICP is any pressure ≥ 20 mm Hg. Increased ICP may result from several etiologies, including trauma, intracranial hemorrhage, mass lesions, cerebral edema, increased CSF production, and decreased CSF absorption. Increased Intracranial Pressure (ICP)) > 30 mm Hg within a closed fascial space causing reduced tissue perfusion. Patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship present with paresthesia, pallor, pulselessness Pulselessness Cardiac Arrest, and severe pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways that worsens with passive stretching. Diagnosis is made on the basis of clinical findings. Measurement of ICP ICP Normal intracranial pressure (ICP) is defined as < 15 mm Hg, whereas pathologically increased ICP is any pressure ≥ 20 mm Hg. Increased ICP may result from several etiologies, including trauma, intracranial hemorrhage, mass lesions, cerebral edema, increased CSF production, and decreased CSF absorption. Increased Intracranial Pressure (ICP) is not necessary. Radiographs should be obtained if a fracture Fracture A fracture is a disruption of the cortex of any bone and periosteum and is commonly due to mechanical stress after an injury or accident. Open fractures due to trauma can be a medical emergency. Fractures are frequently associated with automobile accidents, workplace injuries, and trauma. Overview of Bone Fractures is suspected. Management involves immediate surgical fasciotomy Fasciotomy Surgical incision on the fascia. It is used to decompress compartment pressure (e.g. in compartment syndromes; circumferential burns and extremity injuries) or to release contractures (e.g. in dupuytren’s contracture). Compartment Syndrome.