A pulmonary embolism is a blockage in the pulmonary artery, the blood vessel that carries blood from the heart to the lungs.

This blockage – usually a blood clot – is potentially life-threatening because it can prevent blood from reaching your lungs.

The symptoms of a pulmonary embolism can sometimes be difficult to recognise because they can vary between individuals. However, the main symptoms include:

  • chest pain – a sharp, stabbing pain that may be worse when you breathe in
  • shortness of breath – which can come on suddenly or develop gradually
  • coughing – this is usually dry, but may include coughing up blood or mucus that contains blood
  • feeling faint, dizzy or passing out

You should visit your GP as soon as possible if you have a combination of these symptoms.

If your symptoms are particularly severe, dial 999 immediately and ask for an ambulance.

Read more about diagnosing a pulmonary embolism.

What causes a pulmonary embolism?

A pulmonary embolism is often caused by a blood clot travelling up from one of the deep veins in your legs to your heart and lungs.

A blood clot in one of the deep veins of the legs is known as deep vein thrombosis (DVT). DVT can occur for no apparent reason, but it often develops after long periods of inactivity, such as during a long-haul flight or if you're ill in hospital.

DVT can also occur during pregnancy or as a result of some medical conditions, such as cancer or heart failure, or if the wall of a blood vessel becomes damaged.

Read more about the causes of a pulmonary embolism.

Diagnosing a pulmonary embolism

Diagnosing a pulmonary embolism can be difficult because the symptoms are common to many other conditions. However, an accurate diagnosis is important because treating a pulmonary embolism isn't always easy and the treatment used can cause side effects.

A number of tests can help determine whether you have a pulmonary embolism or rule out other causes of your symptoms. For example, you may have a chest X-ray or tests to check how well your lungs are working.

Read more about how a pulmonary embolism is diagnosed.

How a pulmonary embolism is treated

Pulmonary embolisms are treated with anticoagulant medicines. These stop the blood clot getting bigger while your body slowly reabsorbs it, and reduce your risk of further clots developing.

If you're diagnosed with a pulmonary embolism, you'll usually be given regular anticoagulant injections for about five days to begin with. You'll also be prescribed an anticoagulant tablet called warfarin to take for several months.

As part of your treatment, you'll need regular blood tests to check that the dose of warfarin you're receiving is correct. If the dose is too high you may experience bleeding and if it's too low you may have further blood clots.

Keeping mobile will also help you maintain good blood circulation and prevent further blood clots forming.

Read more about treating a pulmonary embolism.

Preventing a pulmonary embolism

A number of methods may be recommended to prevent a pulmonary embolism if you're at risk of developing blood clots. These include:

  • taking anticoagulant tablets, such as warfarin
  • wearing compression stockings or using compression devices
  • avoiding long periods of inactivity
  • leading a healthy lifestyle, such as giving up smoking (if you smoke) and eating a healthy, balanced diet low in fat and including plenty of fruit and vegetables

Read more about preventing a pulmonary embolism.

Page last reviewed: 13/07/2015

Next review due: 13/07/2017