Arterial Embolism

Arterial embolism is a sudden interruption of blood flow to an organ or body part caused by an embolus adhering to the arterial wall. The primary type of embolus is a blood clot (thromboembolism), but other materials can also cause emboli. This condition is a major cause of infarction, leading to tissue death due to the lack of blood supply.

Signs and Symptoms

Symptoms of arterial embolism can vary depending on the location and size of the embolus. Generally, the symptoms include pain in the affected body part and temporarily decreased organ function. Later symptoms may involve signs of infarction, leading to permanently decreased organ function.

For instance, myocardial infarction symptoms include chest pain, dyspnea, diaphoresis, weakness, light-headedness, nausea, vomiting, and palpitations. Limb infarction symptoms encompass coldness, decreased or absent pulse beyond the blockage, pain, muscle spasm, numbness, tingling, pallor, and muscle weakness, potentially leading to paralysis.

Commonly Occluded Sites

Arterial emboli commonly occur in the legs and feet, but they can also affect the brain, causing strokes, or the heart, causing heart attacks. Less frequent sites include the kidneys, intestines, and eyes.

Risk Factors

Risk factors for arterial embolism include disturbed blood flow, arterial wall injury, and hypercoagulability. Specific conditions like atrial fibrillation, mitral stenosis, and endocarditis increase the risk. Atherosclerosis is a significant risk factor, with associated risks such as advanced age, cigarette smoking, hypertension, obesity, hyperlipidaemia, diabetes mellitus, sedentary lifestyle, and stress.

Other risk factors include recent surgery, previous stroke or cardiovascular disease, long-term intravenous therapy, and bone fractures. Paradoxical embolisation can occur in individuals with a septal defect of the heart, where a clot passes from veins into arteries through the heart.

Pathophysiology

Arterial embolism results from emboli blocking blood flow in an artery, causing ischaemia and possibly infarction with tissue necrosis. Collateral circulation may compensate for the loss of arterial flow but develops slowly, making sudden embolisation more very important than gradual occlusion.

Materials

Arterial embolisms can consist of various materials:

• Thromboembolism (blood clot)
• Cholesterol embolism (from atherosclerotic plaque)
• Fat embolism (from bone fractures or fat droplets)
• Air embolism (air bubbles)
• Septic embolism (pus containing bacteria)
• Cancer embolism

Diagnosis

Diagnosis involves evaluating symptoms and may include tests such as Doppler ultrasound, echocardiography, arteriography, MRI, blood tests for elevated enzymes, blood cultures, ECG, and angioscopy.

Prevention

Preventing atherosclerosis through diet, exercise, and smoking cessation is very important. High-risk individuals may take antithrombotic medications like warfarin or antiplatelet drugs prophylactically.

Treatment

Treatment aims to control symptoms and restore blood flow. Medications include antithrombotic drugs (anticoagulants, antiplatelet medication, thrombolytics), painkillers, and vasodilators. Intra-arterial thrombolysis can be used to deliver antithrombotic agents directly to the clot.

Surgical options include arterial bypass surgery and embolectomy using techniques like thromboaspiration, angioplasty with balloon catheterisation, and open surgery. In severe cases, amputation may be necessary.

Prognosis

The prognosis depends on the clot location and blockage extent. Without treatment, arterial embolism has a high mortality rate, and the affected area can suffer permanent damage. Arterial emboli may recur even after successful treatment.

Complications

Complications vary by blockage site and can include myocardial infarction, transient ischaemic attack, stroke, necrosis, gangrene, and septic shock.

Epidemiology

In the United States, approximately 550,000 people die annually from heart-related arterial embolism and thrombosis. Among these, around 100,000 deaths are considered premature.

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Self-assessment MCQs (single best answer)

What is the primary type of embolus causing arterial embolism?

Which of the following is a common symptom of myocardial infarction?

What is a significant risk factor for arterial embolism?

Which diagnostic test is used to visualise blood flow and detect blockages in arteries?

What type of embolism is caused by air bubbles entering the bloodstream?

Which medication is commonly used to prevent clot formation in high-risk individuals?

What is the term for temporary decreased organ function due to arterial embolism?

Which of the following is NOT a common site for arterial emboli?

What is a common complication of untreated arterial embolism?

Which surgical option might be used to restore blood flow in arterial embolism?