What is a pleural effusion?

You have 2 pleural membranes that line the outside of your lungs and the inside of your chest wall. The space between these membranes contains a small amount of fluid called pleural fluid. This fluid helps your lungs and chest wall to move smoothly during breathing.

If you have a build-up of fluid in the pleural space, it's known as a pleural effusion.

What are the symptoms of a pleural effusion?

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

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

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

What causes a pleural effusion?

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

• heart failure
• chest infections such as pneumonia or tuberculosis
• cancer
• pulmonary embolism (a blood clot in your lungs)
• kidney disease or kidney failure
• liver cirrhosis

Pleural effusions can also happen after chest surgery and with certain medicines.

When should I see my doctor?

If you have severe chest pain or feel breathless, call triple zero (000) for an ambulance.

See your doctor urgently if you have sharp chest pain that is worse when you breathe in and a cough.

How is a 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.

Your doctor may organise for you to have a chest x-ray.

Sometimes your doctor recommend other tests such as:

• blood tests
• an ultrasound scan
• a CT scan

Pleural effusion fluid may be watery, or it can contain blood or pus. A procedure called a pleural tap can remove some of the fluid to be tested. This involves using a needle to take a small sample of the fluid.

A pleural tap can be done with ultrasound scan guidance to help get the needle in the right place.

How is a pleural effusion treated?

Treatment depends on:

• the cause of your pleural effusion
• how severe it is
• your symptoms

If your 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.

In some cases, your doctor may recommend draining the pleural effusion. The fluid can be drained with a needle inserted through your chest wall and a chest tube.

In some cases, you may need to stay in hospital after the fluid is drained. Sometimes, surgery may be recommended if other treatments are not working.

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

What are the complications of a pleural effusion?

It's possible to develop a pneumothorax (air in the pleural space) after draining a pleural effusion.

Another complication of draining a pleural effusion too quickly is pulmonary oedema (fluid in the lungs).

Your doctor will take care to avoid these complications as much as possible.

Can a pleural effusion be prevented?

It's possible to take steps to reduce your chance of pleural effusion due to some causes. You can:

• get vaccinated against pneumococcal disease to help prevent pneumonia
• quit smoking or vaping to lower your chance of getting cancer
• make lifestyle changes to reduce your risk of heart disease

Resources and Support

If you want to know more about pleural effusion, talk to your doctor or call healthdirect on 1800 022 222 (known as NURSE-ON-CALL in Victoria). A registered nurse is available to speak to, 24 hours, 7 days a week.