Pleural effusion

4-minute read

Key facts

A pleural effusion is an abnormal build-up of fluid in the space around your lungs.
This can cause pressure on your lungs, making breathing difficult.
A pleural effusion can be a sign of serious illness.
Your doctor may use a needle or tube to drain the fluid, which can also be sent off for testing.

What is pleural effusion?

The pleural cavity is a space between your lungs and the inside of your chest. If you have a build-up of fluid in the pleural cavity, this is known as a pleural effusion.

What causes pleural effusion?

Pleural effusion can be caused by many different conditions, including:

heart failure
infections such as pneumonia or tuberculosis
cancer
pulmonary embolism
heart surgery or chest injury
kidney failure or liver disease

Pleural effusion fluid is located outside the lungs. It is different to pulmonary oedema, which occurs when fluid collects in the air sacs inside the lungs themselves.

What are the symptoms of pleural effusion?

Depending on the cause and the size of the pleural effusion, you might have:

difficulty breathing, especially when lying down
cough
fever
pain in your chest, which may get worse when taking a deep breath

Some people who have a pleural effusion have minimal or no symptoms.

If you are experiencing the symptoms of pleural effusion, you should see your doctor.

How is pleural effusion diagnosed?

To diagnose a pleural effusion, your doctor will ask about your symptoms and medical history. They will also examine your chest. This involves listening to your breathing with a stethoscope and tapping on your chest. They may refer you for other tests, such as a chest x-ray.

Sometimes your doctor may also refer you for additional tests such as:

Pleural effusion fluid may be watery, or it can contain blood or pus. Your doctor may refer you for further tests to investigate what type of pleural effusion you have. A procedure called a pleural tap can remove some of the fluid to be tested.

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How is pleural effusion treated?

The treatment depends on the cause of your pleural effusion and how severe it is. If the pleural effusion is small and not causing any problems, your doctor might leave it alone while treating the cause, such as heart failure or infection. Treating the cause will often make the pleural effusion disappear.

If the pleural effusion is making you very short of breath, your doctor might recommend having it drained. The fluid can be drained with a needle inserted through the chest wall or a chest drain. In some cases, you may need to stay in hospital after the fluid is drained.

If the effusion keeps coming back, there are ways to stop it recurring. You can discuss this with your doctor.