This information is for people newly diagnosed with a pulmonary embolism.
What is a pulmonary embolism (PE) and what are the symptoms?
A pulmonary embolism (PE) happens when a blood vessel in your lungs becomes blocked by a blood clot. This can happen very quickly and can be serious. Fast medical treatment can be lifesaving.
The symptoms of a PE can sometimes be difficult to recognise because they can vary between different people. The main symptoms of a PE are:
- sudden onset chest pain
- difficulty taking deep breaths
- feeling short of breath
- coughing (with blood stained phlegm)
- fast heartbeat
- feeling faint or even passing out.
What causes a PE?
Usually, a PE is caused by a blood clot travelling up from one of the deep veins in your legs. This kind of clot is called a deep vein thrombosis (DVT). Sometimes a reason cannot be found as to why the blood clot has formed. However associated risk factors for blood clots include:
- previous blood clots or a family history of blood clots
- pregnancy
- use of the oral contraceptive pill or hormone replacement tablets
- surgery or reduced mobility (for example, leg plaster casts)
- long haul flights (and other forms of travel if more than four hours in duration)
- smoking
- being overweight
- increasing age
- cancer
- underlying condition of ‘sticky blood’.
Sometimes, you may need some tests to look into why you had the blood clot. If this is needed, your team will refer you to see a specialist.
How is a PE treated?
If you need treatment for a PE, you will almost always be admitted to hospital for a few days. If your clot is small however, you may not need to be admitted and can be treated as an outpatient.
Taking anticoagulant medicines
The main treatment is called an anticoagulant (‘blood thinner’). This is a medicine that causes chemical changes in your blood to stop it clotting easily. It will stop the clot getting larger while your body slowly absorbs it and reduces the risk of further clots developing. There are many types of anticoagulants, and your health care professional will select the best one for you. This may be as injections or tablets. In all cases, you should expect to receive specific information about the medicine before you leave the hospital.
Are there any other ways to treat a PE?
Occasionally and in very severe cases, other treatments may be needed to remove or break up a blood clot. This might be with a medicine called a thrombolytic (‘clot buster’) or less commonly, with surgery. If you need one of these treatments, you will still need to receive an anticoagulant afterwards.
How long will I need to take the anticoagulant?
You will usually be recommended to take the medicine for three to six months. Some people may need to take them for longer or sometimes lifelong. Specialist blood tests may be needed to help with this decision and if needed, you will be referred to a specialist.
How long will I feel breathless?
It is common to feel breathless for a few weeks or months after a pulmonary embolism. But if these symptoms last for more than eight weeks, talk to a health care professional. There are lots of conditions that can make you feel short of breath after a PE. Your healthcare professional will review this further.
Will I have a follow-up appointment?
Once you have been diagnosed with a PE you will be referred to an anticoagulation clinic. The team will check that there are no problems with the medicine you are taking perform any blood tests if needed and answer any questions that you may have. We may refer you to a general medicine clinic or thrombosis clinic for further investigations if needed.
When do I need to seek immediate medical attention?
You must seek immediate medical attention if your symptoms worsen, or if you develop any new symptoms, such as:
- chest pain or breathlessness
- coughing or vomiting blood
- increased leg swelling.
What do I need to do after I go home?
Exercise and rest: You may find that you are not able to do as much physical activity as normal due to your symptoms. Avoid long periods of exercise in the first few weeks if don’t feel well enough to do it. If you need a painkiller, paracetamol is considered to be safe to take with anticoagulant medicines.
Aspirin and other anti-inflammatory medicines (for example ibuprofen, naproxen or diclofenac) should be avoided, unless under the guidance of your GP. This is because they may interfere with your treatment and potentially increase the risks of bleeding.
Other medication: Always check with your GP or pharmacist before taking any medication, including herbal or alternative treatments, to make sure they are safe to take with your treatment.
Diet: Try to eat a healthy, balanced diet and to avoid excessive changes in your weight. Alcohol intake may interfere with your anticoagulant treatment, so we recommend that you do not drink more than one to two units of alcohol per day. Speak to a healthcare professional for more advice, especially if you are due to start warfarin. Alcohol can also increase your risk of falls and injuries, which can be more serious if you are taking an anticoagulant.
Travel: Avoid for two weeks. Then you can travel if you feel well, with no shortness of breath on routine exercise.
Other information
In general, anyone who has had a PE (or DVT) is at a higher risk of having a blood clot in the future, compared to someone who has never had a blood clot. It is important to tell any healthcare professional that you see, about your history of blood clots as this may affect your treatment.
Useful sources of information:
NHS Choices: www.
Thrombosis UK: https://
UCLH cannot accept responsibility for information provided by other organisations.
Contact Details
Emergency Services Division
4th Floor East
250 Euston Road
London
NW1 2PG
Page last updated: 30 May 2024
Review due: 31 October 2025