Pulmonary Embolism

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Pulmonary Embolism

Pulmonary Embolism

Blood clot moving from a blood vessel in the leg to the lungs, with close-ups showing the blood clot in the lung.

A pulmonary embolism (PE) is a sudden blockage or decrease of blood flow in one or both lungs that happens when a clot travels into the arteries of the lung (pulmonary arteries). Most blockages come from a blood clot that forms in the vein of a leg or arm (deep vein thrombosis, DVT) and travels to the lungs. A clot is blood that has thickened into a gel or solid. PE is a dangerous and life-threatening condition that needs to be treated right away.

What are the causes?

This condition is usually caused by a blood clot that forms in a vein and moves to the lungs. In rare cases, it may be caused by air, fat, part of a tumor, or other tissue that moves through the veins and into the lungs.

What increases the risk?

The following factors may make you more likely to develop this condition:
  • Experiencing a traumatic injury, such as breaking a hip or leg.
  • Having:
    • A spinal cord injury.
    • Major surgery, especially hip or knee replacement, or surgery on parts of the nervous system or on the abdomen.
    • A stroke.
    • A blood-clotting disease.
    • Long-term (chronic) lung or heart disease.
    • Cancer, especially if you are being treated with chemotherapy.
    • A central venous catheter.
  • Taking medicines that contain estrogen. These include birth control pills and hormone replacement therapy.
  • Being:
    • Pregnant.
    • In the period of time after your baby is delivered (postpartum).
    • Older than age 60.
    • Overweight.
    • A smoker, especially if you have other risks.
    • Not very active (sedentary), not being able to move at all, or spending long periods sitting, such as travel over 6 hours. You are also at a greater risk if you have a leg in a cast or splint.

What are the signs or symptoms?

Symptoms of this condition usually start suddenly and include:
  • Shortness of breath during activity or at rest.
  • Coughing, coughing up blood, or coughing up bloody mucus.
  • Chest pain, back pain, or shoulder blade pain that gets worse with deep breaths.
  • Rapid or irregular heartbeat.
  • Feeling light-headed or dizzy, or fainting.
  • Feeling anxious.
  • Pain and swelling in a leg. This is a symptom of DVT, which can lead to PE.

How is this diagnosed?

This condition may be diagnosed based on your medical history, a physical exam, and tests. Tests may include:
  • Blood tests.
  • An ECG (electrocardiogram) of the heart.
  • A CT pulmonary angiogram. This test checks blood flow in and around your lungs.
  • A ventilation–perfusion scan, also called a lung VQ scan. This test measures air flow and blood flow to the lungs.
  • An ultrasound to check for a DVT.

How is this treated?

Treatment for this condition depends on many factors, such as the cause of your PE, your risk for bleeding or developing more clots, and other medical conditions you may have. Treatment aims to stop blood clots from forming or growing larger. In some cases, treatment may be aimed at breaking apart or removing the blood clot. Treatment may include:
  • Medicines, such as:
    • Blood thinning medicines, also called anticoagulants, to stop clots from forming and growing.
    • Medicines that break apart clots (fibrinolytics).
  • Procedures, such as:
    • Using a flexible tube to remove a blood clot (embolectomy) or to deliver medicine to destroy it (catheter-directed thrombolysis).
    • Surgery to remove the clot (surgical embolectomy). This is rare.

You may need a combination of immediate, long-term, and extended treatments. Your treatment may continue for several months (maintenance therapy) or longer depending on your medical conditions. You and your health care provider will work together to choose the treatment program that is best for you.

Follow these instructions at home:


  • Take over-the-counter and prescription medicines only as told by your health care provider.
  • If you are taking blood thinners:
    • Talk with your health care provider before you take any medicines that contain aspirin or NSAIDs, such as ibuprofen. These medicines increase your risk for dangerous bleeding.
    • Take your medicine exactly as told, at the same time every day.
    • Avoid activities that could cause injury or bruising, and follow instructions about how to prevent falls.
    • Wear a medical alert bracelet or carry a card that lists what medicines you take.
  • Understand what foods and drugs interact with any medicines that you are taking.

General instructions

  • Ask your health care provider when you may return to your normal activities. Avoid sitting or lying for a long time without moving.
  • Maintain a healthy weight. Ask your health care provider what weight is healthy for you.
  • Do not use any products that contain nicotine or tobacco. These products include cigarettes, chewing tobacco, and vaping devices, such as e-cigarettes. If you need help quitting, ask your health care provider.
  • Talk with your health care provider about any travel plans. It is important to make sure that you are still able to take your medicine while traveling.
  • Keep all follow-up visits. This is important.

Where to find more information

Contact a health care provider if:

  • You missed a dose of your blood thinner medicine.
  • You have a fever.

Get help right away if:

  • You have:
    • New or increased pain, swelling, warmth, or redness in an arm or leg.
    • Shortness of breath that gets worse during activity or at rest.
    • Worsening chest pain.
    • A rapid or irregular heartbeat.
    • A severe headache.
    • Vision changes.
    • A serious fall or accident, or you hit your head.
    • Blood in your vomit, stool, or urine.
    • A cut that will not stop bleeding.
  • You cough up blood.
  • You feel light-headed or dizzy, and that feeling does not go away.
  • You cannot move your arms or legs.
  • You are confused or have memory loss.

These symptoms may represent a serious problem that is an emergency. Do not wait to see if the symptoms will go away. Get medical help right away. Call your local emergency services (911 in the U.S.). Do not drive yourself to the hospital.


  • A pulmonary embolism (PE) is a serious and potentially life-threatening condition. It happens when a blood clot from one part of the body travels to the arteries of the lung, causing a sudden blockage or decrease of blood flow to the lungs. This may result in shortness of breath, chest pain, dizziness, and fainting.
  • Treatments for this condition usually include medicines to thin your blood (anticoagulants) or medicines to break apart blood clots.
  • If you are given blood thinners, take your medicine exactly as told by your health care provider, at the same time every day. This is important.
  • Understand what foods and drugs interact with any medicines that you are taking.
  • If you have signs of PE or DVT, call your local emergency services (911 in the U.S.).

This information is not intended to replace advice given to you by your health care provider. Make sure you discuss any questions you have with your health care provider.