Pulmonary Embolism

Medically reviewed by Daniel Murrell, MD on November 15, 2017Written by Brian Krans

What is a pulmonary embolism?

A pulmonary embolism is a blood clot that occurs in the lungs.

It can damage part of the lung due to restricted blood flow, decrease oxygen levels in the blood, and affect other organs as well. Large or multiple blood clots can be fatal.

The blockage can be life-threatening. According to the Mayo Clinic, it results in the death of one-third of people who go undiagnosed or untreated. However, immediate emergency treatment greatly increases your chances of avoiding permanent lung damage.

What causes a pulmonary embolism?

Blood clots can form for a variety of reasons. Pulmonary embolisms are most often caused by deep vein thrombosis, a condition in which blood clots form in veins deep in the body. The blood clots that most often cause pulmonary embolisms begin in the legs or pelvis.

Blood clots in the deep veins of the body can have several different causes, including:

  • Injury or damage: Injuries like bone fractures or muscle tears can cause damage to blood vessels, leading to clots.
  • Inactivity: During long periods of inactivity, gravity causes blood to stagnate in the lowest areas of your body, which may lead to a blood clot. This could occur if you’re sitting for a lengthy trip or if you’re lying in bed recovering from an illness.
  • Medical conditions: Some health conditions cause blood to clot too easily, which can lead to pulmonary embolism. Treatments for medical conditions, such as surgery or chemotherapy for cancer, can also cause blood clots.
There are additional risk factors that increase your odds of having the type of blood clot that can cause pulmonary embolism.

What are the risk factors for a pulmonary embolism?

Factors that increase your risk of developing deep vein thrombosis and pulmonary embolism include:

  • cancer
  • a family history of embolisms
  • fractures of the leg or hip
  • hypercoagulable states or genetic blood clotting disorders, including Factor V Leiden, prothrombin gene mutation, and elevated levels of homocysteine
  • a history of heart attack or stroke
  • major surgery
  • obesity
  • a sedentary lifestyle
  • age over 60 years
  • taking estrogen or testosterone

What are the symptoms of a pulmonary embolism?

Symptoms of a pulmonary embolism depend on the size of the clot and where it lodges in the lung.

The most common symptom of a pulmonary embolism is shortness of breath. This may be gradual or sudden.

Other symptoms of a pulmonary embolism include:

If you notice one or more of these symptoms, especially shortness of breath, you should seek medical attention immediately.

Read more: How to tell if you have a blood clot »

How is a pulmonary embolism diagnosed?

In some cases, a pulmonary embolism can be difficult to diagnose. This is especially true if you have an underlying lung or heart condition, such as emphysema or high blood pressure.

When you visit your doctor for your symptoms, they’ll ask about your overall health and any pre-existing conditions you may have.

Your doctor will typically perform one or more of the following tests to discover the cause of your symptoms:

  • chest X-ray: This standard, noninvasive test allows doctors to see your heart and lungs in detail, as well as any problems with the bones around your lungs.
  • electrocardiography (ECG): This test measures your heart’s electrical activity.
  • MRI: This scan uses radio waves and a magnetic field to produce detailed images.
  • CT scan: This scan gives your doctor the ability to see cross-sectional images of your lungs. A special scan called a V/Q scan may be ordered.
  • pulmonary angiography: This test involves making a small incision so your doctor can guide specialized tools through your veins. Your doctor will inject a special dye so that the blood vessels of the lung can be seen.
  • duplex venous ultrasound: This test uses radio waves to visualize the flow of blood and to check for blood clots in your legs.
  • venography: This is a specialized X-ray of the veins of your legs.
  • D-dimer test: A type of blood test.

How is a pulmonary embolism treated?

Your treatment for a pulmonary embolism depends on the size and location of the blood clot. If the problem is minor and caught early, your doctor may recommend medication as treatment. Some drugs can break up small clots.

Drugs your doctor may prescribe include:

  • anticoagulants: Also called blood thinners, the drugs heparin and warfarin prevent new clots from forming in your blood. They can save your life in an emergency situation.
  • clot dissolvers (thrombolytics): These drugs speed up the breakdown of a clot. They’re typically reserved for emergency situations because side effects may include dangerous bleeding problems.

Surgery may be necessary to remove problematic clots, especially those that restrict blood flow to the lungs or heart. According to the Mayo Clinic, some surgical procedures your doctor may use in the case of a pulmonary embolism include:

  • vein filter: Your doctor will make a small incision, then use a thin wire to install a small filter in your inferior vena cava. The vena cava is the main vein that leads from your legs to the right side of your heart. The filter prevents blood clots from traveling from your legs to your lungs.
  • clot removal: A thin tube called a catheter will suction large clots out of your artery. It isn’t an entirely effective method because of the difficulty involved, so it’s not always a preferred method of treatment.
  • open surgery: Doctors use open surgery only in emergency situations when a person is in shock or medications aren’t working to break up the clot.

Follow-up care

After you receive proper treatment for a pulmonary embolism at the hospital, you’ll be advised to treat the underlying cause. This is typically deep vein thrombosis.

You’ll most likely start taking anticoagulant medications, such as heparin and warfarin, to prevent blood clots from returning. You may also need to use compression stockings (they are similar to really tight socks) or another device to prevent clots from forming in your legs.

Regularly exercising your legs is also a key component of therapy after a pulmonary embolism. Your doctor will give you complete instructions on how to care for yourself to prevent future blood clots.

Types of pulmonary embolisms

Q:

Are there different types of pulmonary embolisms?

A:

The most common type of PE is a blood clot. It is possible that anything that gets in the bloodstream and then lodges in the smaller pulmonary arteries can be a pulmonary embolism. Examples are fat from the marrow of a broken bone, a part of a tumor or other tissue, or air bubbles. A rare type of embolism occurs during pregnancy, usually during delivery or immediately after the baby is born. Some of the amniotic fluid that surrounds the baby gets in the mother’s bloodstream and travels to the lungs.

Deborah Weatherspoon, PhD, MSN, RN, CRNAAnswers represent the opinions of our medical experts. All content is strictly informational and should not be considered medical advice.
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