Published: 18 Jun 2025

ICD9: 415.1      ICD10: I26.99      ICD11: BB00

A pulmonary embolism (PE) is a blockage in one of the pulmonary arteries in your lungs.
These arteries carry blood from your heart to your lungs to pick up oxygen. The blockage is usually caused by a blood clot that travels to the lungs from another part of the body, most often the deep veins in the legs (deep vein thrombosis or DVT).

Here's a breakdown:

Pulmonary Arteries: These are the blood vessels that carry blood from the heart to the lungs.
Embolism: This refers to a blockage in a blood vessel, usually caused by a blood clot, but sometimes by other materials like fat, air, or tumor cells.
Blood Clot (Thrombus): A collection of blood cells, platelets, and proteins that forms a solid mass.

In simpler terms: Imagine a blood clot forming in your leg. That clot breaks loose and travels through your bloodstream to your lungs, where it gets stuck in one of the arteries that supply blood to the lungs. This blockage is a pulmonary embolism.

Why is it dangerous?

Reduced Blood Flow: The blockage prevents blood from flowing properly to the affected part of the lung.
Decreased Oxygen Levels: Less blood flow means less oxygen can be picked up by the blood in the lungs, leading to lower oxygen levels in the body.
Strain on the Heart: The heart has to work harder to pump blood through the blocked artery, which can weaken the heart, especially the right side.
Lung Damage: In severe cases, the lung tissue beyond the blockage can be damaged or even die (pulmonary infarction).
Can be Fatal: Large PEs can be life-threatening because they can severely reduce blood flow to the lungs, causing organ failure and death.

Risk Factors:

Many factors can increase your risk of developing a PE, including:

Deep vein thrombosis (DVT): The most common cause.
Surgery: Especially hip or knee replacement.
Prolonged immobility: Such as long flights or bed rest.
Cancer: Some cancers increase the risk of blood clots.
Pregnancy: Pregnancy increases blood clotting.
Birth control pills or hormone replacement therapy: These can also increase blood clotting.
Smoking: Damages blood vessels and increases the risk of clots.
Obesity: Increases the risk of DVT.
Genetic factors: Some people have inherited conditions that make them more prone to blood clots.

Symptoms:

Symptoms of a PE can vary depending on the size of the clot and the overall health of the individual. Common symptoms include:

Shortness of breath: Often sudden and unexplained.
Chest pain: Sharp, stabbing, or dull, and may worsen with deep breathing or coughing.
Cough: May produce blood-tinged sputum.
Rapid heartbeat:
Lightheadedness or dizziness:
Sweating:
Anxiety:
Leg pain or swelling: (Often associated with DVT)

Diagnosis:

Diagnosing a PE can be challenging because the symptoms can be similar to other conditions. Common diagnostic tests include:

D-dimer blood test: Measures a substance released when blood clots break down. A high level may indicate a blood clot.
CT pulmonary angiogram (CTPA): A specialized CT scan that uses contrast dye to visualize the pulmonary arteries and look for blockages.
Ventilation/perfusion (V/Q) scan: Uses radioactive tracers to measure air flow (ventilation) and blood flow (perfusion) in the lungs.
Pulmonary angiogram: An invasive procedure that involves inserting a catheter into a blood vessel and injecting contrast dye into the pulmonary arteries to visualize them. (Less common now due to CTPA advancements)
Echocardiogram: An ultrasound of the heart that can sometimes show signs of strain on the right side of the heart caused by a PE.

Treatment:

Treatment for a PE typically involves:

Anticoagulants (blood thinners): These medications prevent new clots from forming and prevent existing clots from getting larger. Common anticoagulants include heparin, warfarin, and direct oral anticoagulants (DOACs) like rivaroxaban, apixaban, edoxaban, and dabigatran.
Thrombolytics (clot busters): These medications can dissolve blood clots quickly. They are typically used in severe cases of PE.
Embolectomy: Surgical removal of the clot. This is rarely needed.
IVC filter: A small device placed in the inferior vena cava (a large vein in the abdomen) to trap blood clots before they reach the lungs. This is used in some cases when anticoagulants are not effective or cannot be used.

Prevention:

Preventing a PE is important, especially for people at risk. Strategies include:

Moving around regularly: Especially during long periods of sitting or bed rest.
Compression stockings: Can help improve blood flow in the legs.
Anticoagulant medication: May be prescribed for people at high risk, such as those undergoing surgery or with a history of blood clots.
Staying hydrated: Dehydration can increase the risk of blood clots.
Quitting smoking: Smoking damages blood vessels.
Maintaining a healthy weight: Obesity increases the risk of DVT.

Important Note: If you suspect you may have a pulmonary embolism, seek immediate medical attention. It is a serious condition that requires prompt diagnosis and treatment.

Disclaimer: This information is for general knowledge only and does not constitute medical advice. Always consult with a qualified healthcare professional for any health concerns or before making any decisions related to your health or treatment.