Pulmonary Embolism
Topic Overview
What is pulmonary embolism?
Pulmonary embolism is the sudden blockage of an artery in the lung. When the artery is blocked, usually by one or more blood clots, oxygen levels in the blood drop, and blood pressure in the lungs rises.
Pulmonary embolism caused by large clots can cause sudden death, usually within 30 minutes of when symptoms begin.1 Smaller clots may cause permanent damage to the lungs.
What causes pulmonary embolism?
The most common cause of pulmonary embolism is a blood clot that forms in a deep vein in your leg, breaks loose, travels to the lungs, and becomes trapped in one of the smaller lung arteries. Other substances, such as tumours, air bubbles, amniotic fluid, or fat that is released into the blood vessels, may also block an artery, but such causes are rare.
What are the symptoms?
Shortness of breath is the most common symptom of pulmonary embolism. You may have sharp chest pain, which can spread to your shoulder, neck, jaw, or arm. You may also have a cough that produces a pink, foamy mucus. Other symptoms may include anxiety, sweating, light-headedness, fainting, rapid heart rate or palpitations, and an impending sense of doom. Symptoms of pulmonary embolism often begin suddenly.
What increases your risk of pulmonary embolism?
A blood clot in the deep leg veins (deep vein thrombosis) is the greatest risk factor for pulmonary embolism. Inactivity, especially long periods of bed rest, long flights, or car trips, increases your risk of pulmonary embolism because of reduced blood circulation. Recent surgery, stroke, heart attack, heart failure, cancer, lung disease, being overweight, using birth control pills, and heavy smoking are also risk factors for pulmonary embolism.
Some people have blood that clots too quickly, and they are more likely to develop clots that cause deep vein thrombosis or pulmonary embolism. Conditions that cause increased clotting include inherited factors, cancer, and severe infections. Injury to a blood vessel also increases the risk of deep vein thrombosis.
How is pulmonary embolism diagnosed?
Many different types of tests—such as spiral CT scan or lung scan—can be used to diagnose pulmonary embolism. However, it can be difficult to diagnose because other conditions, such as a heart attack, panic attack, or pneumonia, can cause similar symptoms.
Your doctor will consider your symptoms and risk factors for pulmonary embolism before deciding which tests you should have first. If you are at risk for pulmonary embolism and have symptoms, you should seek emergency care immediately. Some people with this condition, however, have no symptoms.
How is it treated?
Treatment focuses on preventing another clot from developing and preventing existing clots from growing. Heparin and warfarin are anticoagulant medicines that are most commonly given to prevent the growth of existing blood clots or the development of new blood clots. Blood clots that cause pulmonary embolism often will dissolve on their own in a few weeks or months, although they may never dissolve completely.
In rare cases, other treatments for pulmonary embolism may be considered. Clot-dissolving drugs (thrombolytics) may be used, or a surgeon may remove the clot in a procedure called an embolectomy. To prevent future pulmonary embolism, a filter may be placed inside the large central vein (vena cava) of the body to trap clots and prevent them from travelling to the lungs.
See an illustration of a clot
that may lead to pulmonary embolism.
Frequently Asked Questions
Learning about pulmonary embolism:
Being diagnosed:
Getting treatment:
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| Author: | Douglas Dana Shannon Erstad, MBA/MPH | Last Updated: March 23, 2007 |
| Medical Review: | Anne C. Poinier, MD - Internal Medicine Caroline S. Rhoads, MD - Internal Medicine Jeffrey S. Ginsberg, MD - Hematology | |
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