Pulmonary embolism

What is a pulmonary embolism and what are the symptoms?

A pulmonary embolism happens when a blood vessel in your lungs becomes blocked. Most of the time, this blockage is caused by a blood clot and happens suddenly.

It can be very serious because it can stop blood going to your lungs. Fast medical treatment can be lifesaving.

The symptoms of a pulmonary embolism can sometimes be difficult to recognise because they can vary between different people. And the symptoms of a blood clot to the lungs are also seen in many other lung conditions.

The main symptoms are chest pain, feeling short of breath, coughing and feeling faint or even passing out.

See a GP if you, or someone you care for, has a combination of these symptoms:

A blood clot in your leg can break off and travel to your lungs, so another warning sign can be a painful, red or swollen leg (usually the calf).

Some people with a pulmonary embolism get a lot more breathless than others. Watch out for these symptoms:

  • you suddenly have severe difficulty breathing or
  • your heart is beating very fast and you feel lightheaded or
  • you suddenly get chest pain or
  • someone has passed out

Call 999 for an ambulance or go to A&E if you experience any of them.

Next: Causes of a pulmonary embolism >

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Last medically reviewed: March 2018. Due for review: March 2021

This information uses the best available medical evidence and was produced with the support of people living with lung conditions. Find out how we produce our information. If you’d like to see our references get in touch.