Pulmonary embolism

A pulmonary embolism is a blockage in the pulmonary artery. This is the blood vessel that carries blood from the heart to the lungs. This blockage, usually a blood clot, is potentially life-threatening. If your symptoms are severe, see below, dial 999 immediately and ask for an ambulance.

Symptoms of pulmonary embolism

The symptoms of a pulmonary embolism can sometimes be difficult to recognise. This is because they can vary between individuals.

Symptoms can 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 or GP out of hours services as soon as possible if you have a combination of the symptoms above.

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

Causes of a pulmonary embolism

A pulmonary embolism is usually 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 obvious reason. But DVT 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. It can also be as a result of some medical conditions, such as cancer or heart failure, or if the wall of a blood vessel becomes damaged.

Diagnosing a pulmonary embolism

Diagnosing a pulmonary embolism can be difficult because the symptoms are common to many other conditions.

A number of tests can help to find out whether you have a pulmonary embolism or rule out other causes of your symptoms.

An accurate diagnosis is important to make sure you get the right treatment, or avoid unnecessary treatment.

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. They also reduce your risk of further clots developing.

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


The information on this page has been adapted from original content from the NHS website.

For further information see terms and conditions.

This page was reviewed November 2018

This page is due for review December 2020

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