Venous thromboembolism

About a PE

What are the causes and symptoms of a PE?

Nearly all cases of PE are caused by a DVT, but PE can occur without evidence of a DVT. It is estimated that about 1 in 1,000 people have a DVT each year in the UK. If untreated, about 1 in 10 people with a DVT will develop a PE.1

Risk factors for developing a DVT and a PE include:

  • age – older people are more likely to have a DVT than younger people
  • immobility caused by long travel journeys, illnesses or injuries
  • having a recent operation
  • pregnancy
  • having severe pre-existing medical illnesses such as cancer, heart problems or respiratory disease
  • previous experience of a DVT or PE
  • taking hormone-based treatment, such as the contraceptive pill and hormone replacement therapy
  • obesity
  • genetic clotting disease
  • smoking

The common symptoms of a PE include:

  • chest pain that is sharp and is worse when taking a deep breath
  • shortness of breath
  • coughing – which is usually dry, but may include coughing up blood or mucus that contains blood
  • sweating
  • feeling light-headed or dizzy
  • passing out

How is a PE diagnosed?

Diagnosing a PE can be difficult because the signs and symptoms vary between individuals and are common to many other conditions.

Tests to diagnose a PE include:

  • A chest X-ray
    • An X-ray will show an image of the inside of your chest and will detail whether a clot has formed in the lungs
  • D-dimer test
    • D-dimer is a protein that is found in the blood after a blood clot has broken down
    • If a blood test shows a high level of D-dimer, it means that pieces of a blood clot could be loose in your blood stream and may become lodged in your lung
  • Computed tomography pulmonary angiography (CTPA)
    • During a CTPA, dye is injected into the blood vessels of your lungs and a CT scan is taken
    • A CT scan is an X-ray that creates a very detailed image of the inside of your body
    • If there is a PE in one of your lungs, it will show up as a gap in your blood supply
  • Ventilation or perfusion scan
    • This scan measures the amount of air and the blood flow in your lungs
    • If this shows that part of your lung has air in it, but no blood supply, it may signify a PE

How is a PE treated?

It is essential to treat a PE as quickly as possible.

Anticoagulation treatment will usually be given to you – this is a type of medication that slows down your body’s ability to clot therefore reducing the likelihood of dangerous blood clots forming in your veins. However, in the case of a massive PE, thrombolytic treatment may be recommended – this medication works by breaking down the clot.

Your doctor will discuss your treatment options in more detail with you.

Can a PE be prevented?

PE can be prevented. However, not all DVT and PE can be prevented as some can occur ‘unprovoked’ by no known risk factors.

A PE is usually the result of an underlying blood clot in the leg known as a DVT. Preventing a DVT, therefore, is an important consideration for your doctor, particularly if you are admitted to hospital for an extended period or having surgery, or have previous experience of a DVT. You may be given an anticoagulant drug to help slow down your body’s ability to clot, and also asked to wear compression stockings.

You can also help prevent a DVT by keeping mobile. If you are going on a long journey, such as coach, train or car, or sitting for any lengthy period, keep hydrated and try to take regular breaks to stretch your legs and feet to help your circulation.



  1. Patient UK – Pulmonary embolism. Available from: accessed June 2020