Pulmonary embolism

A pulmonary embolism happens when a blood clot blocks one or more blood vessels in your lungs. It’s a serious and potentially life-threatening condition if you don’t get a quick diagnosis and treatment.

Causes of pulmonary embolism

The most common cause of a pulmonary embolism is deep vein thrombosis (DVT). This is a blood clot in a vein in your leg or your pelvis. Parts of this clot can break off and travel through your bloodstream. The clots can get stuck in the narrow blood vessels in your lungs. This can affect your blood flow and breathing.

Doctors can’t always find out what’s caused a pulmonary embolism. But some things can increase your risk of developing a blood clot. These include:

• being inactive for long periods of time – for example, after a big operation or sitting still during a long journey of at least four hours
• having blood that clots more easily – this is more likely in people who are overweight, pregnant or taking the contraceptive pill or some forms of hormone replacement therapy (HRT)
• having cancer, including pancreatic cancer, prostate cancer and breast cancer
• after a recent accident or broken bone
• your blood vessels being damaged from an injury or operation
• having a genetic disorder that makes it more likely for your blood to clot

Symptoms of pulmonary embolism

The symptoms of a pulmonary embolism can be vague and persistent for several weeks. Or they can be sudden and severe. Some people have few, if any, symptoms.

Symptoms of a pulmonary embolism may include:

• pain in your chest – especially when taking a deep breath
• feeling short of breath
• coughing up blood
• feeling faint or fainting

Your symptoms may depend on how big the pulmonary embolism is and where it is.

• If the clot is small and in a blood vessel at the outer edge of your lungs, you may have mild symptoms.
• If the blood clot is large and in a central blood vessel, it could cause you to collapse suddenly.

If you have pulmonary embolism symptoms, including difficulty breathing and chest pain, call an ambulance and get medical help as soon as you can. Also get emergency help if you’re pregnant, or have given birth in the last six weeks.

Pulmonary embolism-type symptoms can be caused by other health conditions such as asthma. But if you have any of the above symptoms, it’s important to see a GP as soon as possible.

Diagnosis of pulmonary embolism

If the GP thinks you have signs of a pulmonary embolism, they’ll probably give you some medicines to take straight away. They’ll also arrange for you to go to hospital for assessment as soon as possible. You may already be in hospital (after an operation, for example) when the symptoms start.

At hospital, you may have the following tests.

• A blood test called D-dimer. If the test result is negative, this may help to rule out deep-vein thrombosis and a pulmonary embolism.
• A leg vein ultrasound. This uses sound waves to look at your blood as it flows through the blood vessels in your legs.
• Computed tomography pulmonary angiogram (CTPA). This is a CT scan – dye is injected into your bloodstream to see if there’s a blockage in the arteries (blood vessels) to your lungs.
• Isotope lung scanning (also called ventilation-perfusion or V/Q scanning). You may be offered this test if you have kidney problems or can’t have a CTPA for some other reason. It shows how much blood and air are getting into your lungs.

Your doctor may do other tests such as a chest X-ray, an ECG and blood tests, to check whether you have a pulmonary embolism or another condition.

Treatment of pulmonary embolism

If you have a pulmonary embolism, it’s important that it’s treated quickly. This means you’ll usually begin pulmonary embolism treatment while you’re waiting for tests or test results. You may need to be admitted to hospital if you’re not already in hospital. You may be given oxygen to help you breathe, and fluid through a drip if necessary.

The main pulmonary embolism treatment is a type of medicine called an anticoagulant. You may also need treatment to get rid of the existing clot.

Anticoagulants

Anticoagulants prevent blood clots forming or stop blood clots from getting bigger. Which type of anticoagulant your doctor recommends will depend on a number of things. These include:

• how serious your pulmonary embolism is
• your general health
• local guidelines
• availability of treatment

You take most anticoagulants to treat pulmonary embolism as tablets or capsules. But some anticoagulant medicines are given as an injection.

There are two main types of oral anticoagulant medicine:

• direct oral anticoagulants (DOACs) – for example, apixaban, rivaroxaban, dabigatran, and edoxaban
• warfarin

DOACs may be the first option your doctor recommends. With these medicines, you don’t need to be monitored as closely as with older anticoagulants such as warfarin.

Some people with certain medical conditions or taking some medicines can’t take apixaban or rivaroxaban. If you can’t take these DOACs, your doctor may recommend you have an injection of an anticoagulant called heparin for at least five days. Then you’ll be offered dabigatran or edoxaban tablets or capsules.

If you’re taking warfarin, you’ll need to have a regular blood test to make sure the medicine is having the correct blood-thinning effect. This is called an international normalised ratio (INR) test. You won’t need to be monitored in this way if you’re taking a DOAC.

After a pulmonary embolism, you’ll need to keep taking anticoagulants for at least three months. Depending on your medical history and why you developed a pulmonary embolism, your doctor may recommend you continue taking anticoagulants for longer. This is to prevent more blood clots from developing.

If you’re taking an anticoagulant, your nurse or doctor should give you an anticoagulant information booklet. The booklet includes advice about how to take anticoagulants and any possible side-effects. You’ll also be given an alert card, which you should always carry with you.

Treatments to remove clots

If your doctor thinks you have a life-threatening pulmonary embolism, you may need treatment to remove it. You may be given a type of medicine called a thrombolytic. This helps to dissolve the blood clots.

If you’re seriously unwell with life-threatening blood clots or other treatments haven’t worked, your doctor may suggest an operation to remove the blood clot. This is called an embolectomy. There are several different ways in which this can be done.

• In an embolectomy using a catheter, the surgeon puts a thin tube inside your vein and moves it to where the clot is. They can then break up the clot via the catheter and remove it.
• In open surgery, your surgeon makes a cut in the blood vessel to take out the clot.

Prevention of pulmonary embolism

Preventing pulmonary embolism in hospital

If you’re in hospital for a major operation or because of illness, you may be more likely to develop a deep vein thrombosis or a pulmonary embolism. When you’re in hospital, your nurse or doctor will measure your risk of developing a blood clot. They may ask you to do the following.

• Drink plenty of fluids. If you can’t drink, you may be given fluids through a drip.
• Get up and start moving about as soon as you can after an operation or illness.
• Wear compression stockings to help your circulation.
• Use an intermittent pneumatic compression device. This is an inflatable cuff wrapped around your leg or foot. An electrical pump inflates it, squeezing your deep veins.
• Take anticoagulant medicines, such as heparin.

Reducing risks of pulmonary embolism when travelling

Your risk of developing a blood clot increases on journeys of longer than four hours. But there are some simple steps you can take to reduce your risk.

• Get up and walk around whenever you can.
• Wear loose-fitting clothing.
• Do leg exercises in your seat; such as bending and straightening your knees, feet, and toes every half hour.
• Choose an aisle seat if you can.
• Drink enough water (at least 250ml every 2 hours) so you don’t become dehydrated.
• Don’t drink a lot of alcohol.

You should speak to your GP if:

• you’ve recently had surgery
• you’ve had a blood clot before
• you have other health problems that make developing a clot more likely

They may suggest you wear compression stockings or flight socks while travelling. If you develop a painful and swollen leg or any breathing problems after a long journey, get medical advice as soon as you can. Be aware that it can take hours, days, or even weeks before you notice any pulmonary embolism symptoms.

Pulmonary embolism and pregnancy

You’re four or five times more likely to develop a blood clot (DVT and pulmonary embolism) if you’re pregnant (although it’s rare to get one). You also have a greater chance of having a pulmonary embolism just after you’ve had your baby, especially if you had a caesarean section.

Some anticoagulants may harm a developing baby, so you shouldn’t take these when you’re pregnant. These include warfarin and direct oral anticoagulants (DOACs) such as apixaban, rivaroxaban, dabigatran, and edoxaban. If you’re taking warfarin or other anticoagulant tablets, and think that you might be pregnant, tell your doctor immediately.

If your doctor thinks you’re at high risk of getting a blood clot, they may offer you heparin injections while you’re pregnant. Heparin injections are safe to take when you’re pregnant because the heparin doesn’t pass from you to your baby. You may need to take anticoagulant medicines for at least six weeks after you have your baby.