Pulmonary Embolism: Symptoms, Causes & Treatment

Pulmonary embolism is a medical emergency that occurs when one of the lung arteries or its branches is blocked by a blood clot. This clot usually originates in the deep leg veins (deep vein thrombosis), then breaks off and travels with the blood through the heart to the lungs, blocking the pulmonary artery.

This blockage prevents blood from reaching part of the lung, so oxygen exchange is affected and pressure rises on the right side of the heart. The severity ranges by the size of the clot and the number of arteries involved: it may be small with mild symptoms, or large and life-threatening within minutes. Its main symptoms are sudden shortness of breath and chest pain that worsens with deep breathing and a rapid heartbeat, sometimes with a bloody cough or fainting.

Pulmonary embolism is among the most important causes of preventable sudden death in hospitals, so rapid diagnosis and treatment are extremely important. It is treated mainly with blood thinners that prevent the clot from growing and new clots from forming and allow the body to dissolve it gradually, while in severe cases special clot-dissolving drugs are used. Prevention remains the cornerstone, especially through early movement after surgery, compression stockings and preventive blood thinners for at-risk groups, and avoiding sitting motionless during long travel.

• Sudden shortness of breath.
• Chest pain that worsens with deep inhalation.
• Rapid heartbeat.
• A cough that may contain blood.
• Dizziness or fainting in severe cases.

• A clot traveling from the deep leg veins to the lung (most common).
• Increased blood clotting tendency after surgery or injury.
• Prolonged immobility, pregnancy, and some diseases.

• Previous deep vein thrombosis.
• Surgery, injuries, and immobility.
• Cancer and some clotting disorders.
• Pregnancy, birth-control pills, and long travel.

• CT pulmonary angiography, the most accurate test.
• A D-dimer blood test and oxygen measurement.
• Leg ultrasound to detect the clot source.

Blood thinners

• The main treatment to prevent the clot from growing and new clots from forming, started urgently and continued for a duration set by the doctor.

Severe cases

• Clot-dissolving drugs or interventional procedures in life-threatening cases.
• An inferior vena cava filter in selected cases.

This content is educational and does not replace medical advice; pulmonary embolism is an emergency.

• Circulatory collapse and right-heart failure.
• Sudden death in large untreated cases.
• Chronic pulmonary hypertension.

• Early movement after surgery and avoiding prolonged sitting.
• Compression stockings and preventive blood thinners for at-risk groups.
• Moving and drinking water during long travel.