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Pulmonary embolism (PE)

Blood clot travels up a vein into the lungs, where it blocks an artery A pulmonary embolism (also known as PE) is a very serious medical emergency. It is a blockage in one of the arteries (blood vessels) in your lungs, usually caused by a blood clot. The most common cause of a pulmonary embolism is a deep vein thrombosis (DVT), a clot in one of your legs.

You can have different symptoms depending on how big the clot is and where in the lung it goes to. Small pulmonary embolisms don't always cause symptoms.

Symptoms include:


Because a pulmonary embolism is very serious, if you have any symptoms of a pulmonary embolism, especially if you have one or more risk factors, get immediate medical assistance – call an ambulance on 111.

You may have an increased risk of having a PE for a number of reasons, including some medical conditions and long-distance travel. See Reducing your risk of DVT or PE.

Your doctor will assess all your symptoms and risk factors and decide how likely it is that you have a pulmonary embolism.

If you are at risk, you will need a CT scan of your lung (a special type of X-ray that shows pictures of structures inside your body) or a ventilation-perfusion lung scan (a special test that shows how much blood is getting into your lungs).

You may also have other tests including blood tests, an ECG (heart tracing) and chest X-ray.

Treating a pulmonary embolism

Anticoagulant, or blood thinning, medications are used to stop the clot from getting bigger and new clots from forming. You may have injections for a few days before continuing on anticoagulant tablets. There are two types:

How long you will need to take anticoagulant medication will vary depending on the cause of your PE and your risk factors. You may need to stay on treatment for life.

In severe PE medication is sometimes used to dissolve the clot. Very rarely a filter is placed in a vein to stop more clots moving to the lungs or the clot is removed by surgery.

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Written by HealthInfo clinical advisers. Endorsed by clinical director, Haematology, Canterbury DHB. Last reviewed May 2020.

See also:

Blood-thinning medicines for DVT and PE

Page reference: 49140

Review key: HIDVT-21919