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Pulmonary embolism

This factsheet is for people who have had a pulmonary embolism, or who would like information about it.

A pulmonary embolism is a blockage of a blood vessel in your lungs caused by a blood clot. It can be fatal if the clot blocks the main blood supply to your lungs.

About pulmonary embolism

A pulmonary embolism happens when a blood clot or a piece of a blood clot gets stuck in one of the blood vessels in your lungs. The clot forms somewhere else in your body and is carried to your lungs in your blood. It usually forms in one of the deep veins in your legs. This is called deep vein thrombosis (DVT).

Where a pulmonary embolism occurs

Symptoms of pulmonary embolism

Symptoms of a pulmonary embolism include:

  • chest pain
  • breathlessness and coughing
  • fainting
  • coughing up blood

The symptoms you have and how severe they are will depend on how big the pulmonary embolism is. A small embolism may not cause any symptoms. However, a large embolism can cause shock and sudden collapse.

These symptoms are not necessarily a result of a pulmonary embolism, but if you have any of them you should see your GP. If your symptoms are severe, call for emergency help.

Causes of pulmonary embolism

Most pulmonary embolisms are a result of DVT in your leg. DVT can develop if you're inactive for a long period of time.

You're more likely to get DVT and therefore a pulmonary embolism if you:

  • have recently had major surgery, particularly on your hip or knee
  • are pregnant or have recently had a baby
  • have cancer
  • are confined to bed with a serious illness
  • have had DVT or a pulmonary embolism before
  • have an inherited condition called thrombophilia, which means you're more likely to get blood clots
  • have heart disease or other serious long-term illness
  • take the combined contraceptive pill or hormone replacement therapy (HRT)
  • are travelling for a long distance and aren’t able to move around much
  • are obese
  • smoke

Diagnosis of pulmonary embolism

If you visit your GP with minor symptoms, he or she will ask about your symptoms and medical history, and examine you. If you have more severe symptoms, for example, having trouble breathing or you collapse, you will need to go to hospital urgently.

If your GP thinks you may have had a pulmonary embolism, he or she will refer you to hospital. You may have an electrocardiogram (ECG) to rule out other conditions. An ECG measures the electrical activity in your heart to see how well it's working.

Tests commonly used to diagnose a pulmonary embolism include the following.

  • Blood tests, including a test for a substance called D-dimer. If the test result is negative, this can rule out DVT and a pulmonary embolism.
  • Computed tomography pulmonary angiography (CTPA) – this test uses X-rays to make a three-dimensional image of your lungs. A dye is injected into your veins so that they show up on the X-ray image.
  • Isotope lung scanning. This test can see how much blood is getting into your lungs. It's sometimes done before a CTPA.
  • Chest X-ray, although this doesn’t always show a problem.
  • An ultrasound scan of your legs, to look for DVT.

Treatment of pulmonary embolism

Your doctor may give you injections of a medicine called heparin before your diagnosis has been confirmed. Heparin is an anticoagulant used to prevent blood clots forming, or to stop blood clots getting worse. If your doctor thinks you have a life-threatening pulmonary embolism, you may be given an injection of a thrombolytic medicine (eg alteplase), which helps dissolve fresh blood clots.

If a pulmonary embolism is confirmed, your doctor will prescribe ongoing treatment with an anticoagulant that you take by mouth, such as warfarin. You will usually need to take this medicine for three to six months, or sometimes longer. If you develop an embolism twice for no obvious reason, or are felt to be at high risk of another, you may need lifelong treatment.

Your doctor may suggest putting a filter into the main vein carrying blood to your heart (the inferior vena cava) if, for example, you're at high risk of getting another pulmonary embolism or you can't take anticoagulant medicines. The filter stops any other clots travelling up to your heart and lungs.

Special considerations

If you're pregnant

You’re at a higher risk of a blood clot when you're pregnant. This risk is further increased if you have pre-eclampsia (a condition that affects pregnant women and causes high blood pressure), a long labour or a caesarean delivery.

If you or members of your close family have had DVT or a pulmonary embolism in the past, you may be offered screening for a blood clotting disorder (thrombophilia).

If your doctor thinks you're at high risk of getting a blood clot, he or she may offer you heparin injections during your pregnancy and for six weeks after you have given birth. He or she may also recommend you wear elastic compression stockings.

Prevention of pulmonary embolism

If you're in hospital for an operation or because of illness, the staff will assess your risk of developing DVT. Your doctor may suggest some exercises to keep your legs moving. You will be encouraged to drink enough fluids, or you may be given fluids through a drip if you're unable to drink, so that you don’t become dehydrated.

If you're at high risk of DVT, you will be given daily injections of heparin and your doctor or nurse may recommend that you wear compression stockings to help your circulation. Compression stockings come in different sizes and your nurse will check yours are the right fit for you. You might be asked to wear them after you have had surgery.

Alternatively, you may be fitted with an intermittent pneumatic compression device. This device inflates regularly, putting pressure on your legs to keep the blood flowing.

If you're having major surgery, you’re likely to have injections of heparin after your operation to reduce your risk of getting DVT or a pulmonary embolism. You may need to have these injections for up to six weeks. Alternatively, you may have an anticoagulant medicine that you can take by mouth.

Produced by Kerry McKeagney, Bupa Health Information Team, April 2012.

For answers to frequently asked questions on this topic, see FAQs.

For sources and links to further information, see Resources.

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  • This information was published by Bupa's Health Information Team and is based on reputable sources of medical evidence. It has been reviewed by appropriate medical or clinical professionals. Photos are only for illustrative purposes and do not reflect every presentation of a condition. The content is intended only for general information and does not replace the need for personal advice from a qualified health professional. For more details on how we produce our content and its sources, visit the about our health information page.

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