Pulmonary Embolism: Causes, Symptoms, Types & Tests

Pulmonary embolism (PE) is a sudden, potentially life-threatening medical condition that occurs when a blood clot (or sometimes other substances) blocks an artery in the lungs. This blockage can reduce blood flow, lower oxygen levels, strain the heart, and, if untreated, can be fatal. While it often arises as a complication of deep vein thrombosis (DVT) a clot usually formed in the deep veins of the legs, pulmonary embolism can affect anyone, especially those with certain risk factors like prolonged immobility, surgery, or underlying health conditions. Recognizing its signs and seeking prompt treatment are crucial for saving lives and preventing complications.

What is Pulmonary Embolism?

Pulmonary embolism is defined as a blockage in one of the pulmonary arteries in the lungs, most commonly caused by blood clots that travel from veins in the legs or, less commonly, other parts of the body.

This blockage prevents blood from reaching lung tissue, which:

• Reduces oxygen levels in the blood.
• Increases pressure on the right side of the heart.
• Can damage lung tissue and, in severe cases, lead to death.

Causes of Pulmonary Embolism

Most pulmonary embolisms are the result of deep vein thrombosis (DVT) clots that form in the deep veins, often in the legs or pelvis, and then travel to the lungs.

Key risk factors and causes include:

• Prolonged immobility: Such as during long flights, bed rest, or after surgery.
• Surgery and trauma: Especially orthopedic procedures like hip or knee replacement.
• Medical conditions: Cancer, heart failure, inflammatory bowel disease, and certain autoimmune diseases.
• Blood clotting disorders: Inherited or acquired conditions that make blood more prone to clot.
• Pregnancy and childbirth: Hormonal changes increase clotting risk.
• Obesity and smoking: Both increase risk.
• Age: Risk increases with age, particularly over 60.

In rare cases, other substances like fat (from broken bones), air bubbles, or amniotic fluid can cause pulmonary embolism.

Symptoms of Pulmonary Embolism

Symptoms vary depending on the size of the clot, the number of clots, and the person’s overall health. Common signs include:

• Sudden shortness of breath: Even at rest or with minimal activity.
• Chest pain: Often sharp, stabbing, and worse when breathing deeply (pleuritic pain).
• Cough: Sometimes producing bloody or blood-streaked sputum.
• Rapid heart rate (tachycardia): As the heart compensates for reduced oxygen.
• Lightheadedness or fainting: Especially in large clots.
• Anxiety or a sense of impending doom.

Other symptoms related to DVT (the source of the embolism) may include:

• Swelling in one leg (usually below the knee).
• Warmth, redness, or pain in the leg.

Types of Pulmonary Embolism

While all pulmonary embolisms involve a blockage, doctors often classify them by severity or the material causing the blockage:

Based on severity:

1. Massive (high-risk) PE:
   • Large clots block major pulmonary arteries.
   • Severe symptoms: low blood pressure, shock, fainting.
   • High risk of death if untreated.
2. Submassive (intermediate-risk) PE:
   • Moderate blockage.
   • Normal blood pressure but strain on the right side of the heart.
3. Low-risk PE:
   • Smaller clots.
   • Stable blood pressure and minimal heart strain.

Based on cause:

• Thrombotic PE: Most common; due to blood clots.
• Non-thrombotic PE: Caused by fat, air, amniotic fluid, or tumor fragments.

Understanding the type helps doctors decide the urgency and method of treatment.

Tests Used to Detect Pulmonary Embolism

Diagnosis often begins with a clinical assessment and risk evaluation, followed by imaging and lab tests:

• D-dimer blood test: Measures a substance released when blood clots break down. Elevated levels suggest clotting but aren’t specific to PE.
• CT Pulmonary Angiography (CTPA): Gold standard imaging to directly see clots in lung arteries.
• Ventilation-perfusion (V/Q) scan: Compares air flow and blood flow in lungs to detect mismatched areas.
• Ultrasound of the legs: Checks for DVT, the source of many clots.
• Echocardiogram (heart ultrasound): Detects strain on the right heart, which may suggest a large PE.
• Chest X-ray: Not specific to PE but can rule out other causes of symptoms.

Prompt diagnosis is essential to prevent further clots and reduce the risk of death.

Conclusion

Pulmonary embolism is a critical condition that often starts silently as a blood clot in the legs but can rapidly become life-threatening when it travels to the lungs. Its symptoms like sudden breathlessness, chest pain, and cough  should never be ignored. With advances in diagnostic imaging, early detection has improved, and treatments like anticoagulants, thrombolytic, or surgery can save lives. Preventive steps, especially for those at high risk such as moving during long travel, using compression stockings, and following medical advice after surgery can significantly reduce the chance of developing PE. By understanding pulmonary embolism, its causes, symptoms, and the importance of timely medical care, we can protect ourselves and our loved ones from this often-preventable danger.

Frequently Asked Questions (FAQ’s)

1. What is pulmonary embolism?
Pulmonary embolism is a blockage in one of the arteries in the lungs, usually caused by a blood clot that travels from the legs.

2. Is pulmonary embolism fatal?
It can be life-threatening if large or untreated, but with prompt medical care, many people recover.

3. What are the warning signs of pulmonary embolism?
Sudden shortness of breath, chest pain that worsens when breathing deeply, rapid heartbeat, and sometimes coughing up blood.

4. How is pulmonary embolism diagnosed?
Using imaging tests like CT pulmonary angiography, V/Q scan, and blood tests like D-dimer.

5. Who is at risk for pulmonary embolism?
People with prolonged immobility, recent surgery, pregnancy, obesity, smoking, cancer, or blood clotting disorders.

6. Can pulmonary embolism recur?
Yes, especially without treatment or if risk factors remain.

7. How is pulmonary embolism treated?
With blood thinners, clot-dissolving medications, or sometimes surgery to remove the clot.

8. Can you prevent pulmonary embolism?
Yes; by staying active, using preventive medications after surgery, and treating underlying risk factors.