Overview
A (PE) is a blockage in an artery of the lungs. Most often it is a blood clot from a deep vein, usually in the leg, that broke loose and travelled to the lungs. A clot in a deep vein is called deep vein thrombosis, which has its own article in this library.
A blocked lung artery lowers the oxygen in the blood and strains the heart. It can be life-threatening, but most people recover well when it is found and treated early.
Symptoms
Symptoms can start within minutes or build up over days or weeks. They include:
- Sudden shortness of breath, or fast breathing
- Chest pain that is worse when breathing in or coughing
- A fast heartbeat
- Coughing, sometimes with blood
- Light-headedness, fainting, or a feeling of dread
A clot in a leg may cause pain, swelling, warmth, and skin that looks red, blue or darker than usual. On dark skin the colour change can be harder to see.
When to see a doctor
A swollen, painful leg, or breathlessness that builds up over days, should be checked the same day. If you take a blood thinner, report unusual bruising or bleeding. Tell your doctor if breathlessness or swelling lingers for months after a clot.
Causes
Most pulmonary emboli start as a clot in a deep leg vein that breaks away and lodges in an artery of the lung. Clots form when blood flow slows, when a vein is injured by surgery or trauma, or when infection makes the blood clot more easily. Rarely the blockage is air, fat or a piece of a tumour.
Risk factors
- Recent surgery, or a broken hip or leg bone
- A hospital stay, bed rest, or sitting still for journeys of four hours or more
- Cancer, heart disease or lung disease
- Pregnancy and the first six weeks after childbirth
- Contraceptive pills and menopausal hormone treatment
- Being older or overweight
- A previous clot or a family history of clots
Complications
Untreated, a can cause lasting lung damage and low oxygen levels, and it can be fatal.
After treatment, a few people develop pulmonary hypertension, high in the lung arteries that can lead to heart failure. Breathlessness on effort, swelling or fainting that lasts for months can be signs.
Prevention
- Walking as soon as possible after surgery, illness or bed rest
- On long journeys, moving about every hour or two and drinking water
- Using clot-preventing injections or stockings in hospital, if advised
- Telling doctors about any earlier clot before surgery or hormone medicines
- Staying active, keeping to a healthy weight and not smoking
Diagnosis
A can be hard to diagnose, as its signs resemble other conditions. If one is suspected, treatment may begin before results are back. Tests may include:
- A of the lung arteries with dye (CT pulmonary angiography), the main test
- A D-dimer blood test, which detects a substance released when a clot breaks down
- A scan that compares airflow and blood flow in the lungs (V/Q scan)
- scans of the leg veins and the heart
Treatment
The usual treatment is with anticoagulants, or blood thinners, given as injections or tablets. They stop the clot growing and stop new clots forming, and the body then breaks the clot down. Treatment lasts at least three months. The main risk is bleeding, so tell the doctor about other medicines, including aspirin, and report unusual bleeding.
For a large clot causing severe symptoms, clot-dissolving medicines may be used, or the clot may be removed through a thin tube. People who cannot take blood thinners may have a filter placed in a large vein to catch clots. Some people can be treated at home, but others need hospital care.
Myths and facts
Things people often say about this. Open each one to see what is true.
Myth“Breathlessness and chest pain with a racing heart are just anxiety, gas or a muscle pull, and will pass.”What is true?
Fact
A clot in the lung can cause chest pain, a racing heart and a feeling of dread, which can feel like a panic attack or indigestion. Sudden breathlessness, or chest pain that is worse on breathing in, needs urgent assessment, because a pulmonary embolism can be life-threatening.
Myth“Only people who take long flights get clots.”What is true?
Fact
Long journeys of four hours or more raise the risk, but so do surgery, a broken bone, a hospital stay or bed rest, cancer, pregnancy and the weeks after childbirth, and some hormone medicines such as contraceptive pills.
Myth“Blood thinners melt the clot, so I can stop them once I feel better.”What is true?
Fact
Blood-thinning medicine stops the clot growing and stops new clots forming, and the body breaks the clot down over time. Treatment lasts at least three months, and sometimes longer. Stop it only on the advice of the doctor who prescribed it.
Myth“Clots only happen to older or overweight people.”What is true?
Fact
Age and weight raise the risk, but almost anyone can get a clot. Young and otherwise healthy people can be affected, especially after surgery or an injury, during pregnancy, or while taking hormone medicines.
Questions to ask your doctor
Tick the ones you want answered and take them with you.
Common questions
How is a pulmonary embolism different from a heart attack?
A heart attack is a blocked artery of the heart, while a pulmonary embolism is a blocked artery of the lung. Both can cause sudden chest pain, breathlessness, a fast heartbeat and fainting, so doctors use tests such as an ECG, blood tests and a CT scan to tell them apart. Both are emergencies.
Can I make a full recovery?
Most people recover well if the pulmonary embolism is found and treated early. A few are left with lasting breathlessness or, rarely, pulmonary hypertension, so tell your doctor if symptoms linger for months.
How long will I need blood thinners?
At least three months for most people. Some need longer, for example if no clear cause was found, if clots keep returning or if an ongoing risk such as cancer remains. Your doctor will review it, and the medicine should not be stopped without advice.
Can it happen again?
Yes, clots can return. Taking medicines as directed, going to check-ups, staying active, and telling doctors about your history before surgery or a long journey lower the chance.