Pulmonary Embolism


Pulmonary embolism is the sudden blockage of an artery in the lung. Blood clots in the deep veins of the leg or pelvis (deep vein thrombosis, or DVT) are the most common cause. These blood clots can travel to the lungs.

Pulmonary embolism can be very serious. Because you have had one pulmonary embolism, you are at greater risk for having another one. But you can take steps to prevent another pulmonary embolism by following your doctor’s instructions.

You will probably take a prescription blood-thinning medicine to prevent blood clots. A blood thinner can stop a blood clot from growing larger and prevent new clots from forming.


What are the symptoms of pulmonary embolism?

The most common symptoms of pulmonary embolism are:

  • Sudden shortness of breath.
  • Sudden, sharp chest pain that may get worse when you breathe deeply or cough.
  • A cough. The cough may bring up blood or pink, foamy mucus.

Pulmonary embolism can also cause other symptoms. These include:

  • A fast heart rate.
  • Wheezing.
  • Fainting.

If you have symptoms like these, you need to see a doctor right away, especially if they're sudden and severe. Quick treatment could save your life or reduce the risk of future problems.


What causes pulmonary embolism?

Pulmonary embolism is caused by a blocked artery in the lungs. The most common cause of such a blockage is a blood clot that forms in a deep vein in the leg and travels to the lungs, where it gets lodged in a smaller lung artery. Clots in the deep veins of the arms or pelvis can also lead to a pulmonary embolism.

In rare cases, pulmonary embolism may be caused by other substances. They include:

  • Small masses of infectious material.
  • Fat. It can be released into the bloodstream after some types of bone fractures, surgery, trauma, or severe burns.
  • Air bubbles or substances that get into the blood from trauma, surgery, or medical procedures.
  • Tumors caused by rapidly growing cancer cells.
  • Amniotic fluid.


How can you reduce the risk of a pulmonary embolism?

If you have had pulmonary embolism once, you are more likely to have it again. Blood thinners can help reduce your risk, but they increase your risk of bleeding. If your doctor prescribes blood thinners, be sure you understand how to take your medicine safely.

Daily use of anticoagulant medicines may help prevent recurring pulmonary embolism by stopping new blood clots from forming and stopping existing clots from growing.

The risk of forming another blood clot is highest in the weeks after the first episode of pulmonary embolism. This risk decreases over time. But the risk remains high for months and sometimes years, depending upon what caused the pulmonary embolism. People with recurrent blood clots and/or pulmonary embolism may have to take anticoagulants daily for the rest of their lives. Anticoagulant medicines also are often used for people who are not active due to illness or injury, or people who are having surgery on the legs, hips, belly, or brain.

Other preventive methods may also be used, such as:

  • Avoid sitting for long periods. Get up and walk around every hour or so, or flex your feet often.
  • Get moving as soon as you can after surgery.
  • Wear compression stockings if you are at high risk.
  • If you take blood thinners, take them just the way your doctor tells you to.

Take steps to prevent blood clots from travel, such as walking around every hour. Because of long periods of inactivity, you are at higher risk for blood clots when you are traveling.

Risk Factors

What increases your risk of a pulmonary embolism?

Having a blood clot in the deep vein of your leg and having a previous pulmonary embolism are the two greatest risk factors for pulmonary embolism.

Many things increase your risk for a blood clot. These include:

  • Having slowed blood flow, abnormal clotting, and a blood vessel injury.
  • Age. As people get older (especially older than age 70), they are more likely to develop blood clots.
  • Weight. Being overweight increases the risk for developing clots.
  • Not taking anticoagulant medicine as prescribed, unless your doctor tells you to stop taking it.

Slowed blood flow

When blood does not circulate normally, clots are more likely to develop. Reduced circulation may result from:

  • Long-term bed rest, such as if you are confined to bed after an operation, injury, or serious illness.
  • Traveling and sitting for a long time, especially when traveling long distances by airplane.
  • Leg paralysis. When you use your muscles, the muscles contract, and that squeezes the blood vessels in and around the muscles. The squeezing helps the blood move back toward the heart. Paralysis can reduce circulation because the muscles can't contract.

Abnormal clotting

Some people have blood that clots too easily or too quickly. People with this problem are more likely to form larger clots that can break loose and travel to the lungs. Conditions that may cause increased clotting include:

  • Inherited factors.
    • Some people have an inherited tendency to develop blood clots that can lead to pulmonary embolism.
  • Family history of close relatives, such as a sibling, who has had deep vein thrombosis or pulmonary embolism.
  • Cancer and its treatment.
  • Blood vessel diseases, such as varicose veins, heart attack, heart failure, or a stroke.
  • Pregnancy.
    • A woman's risk for developing blood clots increases both during pregnancy and shortly after delivery.
  • Using hormone therapy or birth control pills or patches.
  • Smoking.

Injury to the blood vessel wall

Blood is more likely to clot in veins and arteries shortly after they are injured. Injury to a vein can be caused by:

  • Recent surgery that involved the legs, hips, belly, or brain.
  • A tube (catheter) placed in a large vein of the body (central venous catheter).
  • Damage from an injury, such as a broken hip, serious burn, or serious infection.


How is pulmonary embolism diagnosed?

It may be hard to diagnose pulmonary embolism. That's because the symptoms are like those of many other problems, such as a heart attack or pneumonia.

A doctor will do a physical exam and ask questions about your past health and your symptoms.

You might have tests to look for blood clots or to rule out other causes of your symptoms. Tests may include:

  • A chest X-ray. This may rule out an enlarged heart or pneumonia.
  • Electrocardiogram (EKG). This may help rule out a possible heart attack.
  • Blood tests, such as a D-dimer. D-dimer levels are usually high in people with pulmonary embolism.
  • A CT scan or CT angiogram. These tests can look for pulmonary embolism or for a blood clot that may cause it.
  • A ventilation-perfusion lung scan. This test scans for abnormal blood flow through the lungs.


How is pulmonary embolism treated?

Doctors usually treat pulmonary embolism with medicines called anticoagulants. They are often called blood thinners, but they don't really thin the blood. They help prevent new clots and keep existing clots from growing.

Most people take a blood thinner for a few months. People at high risk for blood clots may take it for the rest of their lives.

If symptoms are severe and life-threatening, "clot-busting" drugs called thrombolytics may be used. These medicines can dissolve clots quickly, but they increase the risk of serious bleeding. Another option is surgery or a less invasive procedure to remove the clot (embolectomy).

Some people may have a filter put into the large vein (vena cava) that carries blood from the lower body to the heart. A vena cava filter may help keep blood clots from reaching the lungs. This filter might be used if you can't take an anticoagulant.

When to Call

Pulmonary embolism: When to call

Call 911 anytime you think you may need emergency care. For example, call if:

  • You have shortness of breath.
  • You have chest pain.
  • You passed out (lost consciousness).
  • You cough up blood.

Call your doctor now or seek immediate medical care if:

  • You have new or worsening pain or swelling in your leg.

Watch closely for changes in your health, and be sure to contact your doctor if:

  • You do not get better as expected.


How can you care for yourself when you've had pulmonary embolism?

  • Take your medicines exactly as prescribed. Call your doctor if you think you are having a problem with your medicine. You will get more details on the specific medicines your doctor prescribes.
  • If you are taking a blood thinner, be sure you get instructions about how to take your medicine safely. Blood thinners can cause serious bleeding problems.
  • Try to walk several times a day. Walking helps keep blood moving in your legs. Before doing other types of exercise, ask your doctor what type and level of exercise is safe for you.
  • Take steps to help prevent blood clots in your legs. For example:
    • Exercise your lower leg muscles if you sit for long periods of time. Pump your feet up and down by pulling your toes up toward your knees then pointing them down. Repeat.
    • After an illness or surgery, try to get up and out of bed often. If you can't get out of bed, flex your feet every hour to keep the blood moving through your legs.
    • Take plenty of breaks when you travel. On long car trips, stop the car and walk around every hour or so. On the bus, plane, or train, get out of your seat and walk up and down the aisle every hour, if you can.
    • Wear compression stockings if your doctor recommends them.
    • Check with your doctor about whether you should use hormonal forms of birth control or hormone therapy. These may increase your risk of blood clots.
  • Have a healthy lifestyle. This includes being active, staying at a healthy weight, and not smoking.

Copyrighted material adapted with permission from Healthwise, Incorporated. This information does not replace the advice of a doctor.