Fact sheet Patient conditions

Published on 1 Jul 2015

Pleural effusion

What is a pleural effusion?

A pleural effusion is a collection of fluid within the pleural cavity, the space that surrounds the lungs. The lungs are the major organs of the respiratory system.

What does the respiratory system do?

The respiratory system provides oxygen to the body and removes the waste gas carbon dioxide.

As well as needing lungs to breathe, we also need an airway (trachea), a well-functioning nervous system (brain and spinal cord) and working breathing muscles (the diaphragm and the muscles between the ribs).

More about the respiratory system

What causes a pleural effusion?

There are several reasons why fluid may accumulate in the lining of the lung. Medical conditions that can cause a pleural effusion include:

  • heart failure
  • pulmonary embolism
  • pneumonia
  • heart surgery
  • trauma, such as car accidents.

The fluid can be watery, can contain blood (known as haemothorax) or can contain pus (known as empyema).

Signs and symptoms of a pleural effusion

When someone has a pleural effusion, there may not be any signs or symptoms. However if the amount of fluid in the lung lining increases to around 500mL, symptoms such as shortness of breath, decreased chest movement and quieter breathing may start to become noticeable.

Other signs and symptoms of pleural effusion include:

  • increased difficulty in breathing, or shallow breathing
  • fast breathing rate
  • low oxygen saturation levels
  • anxiety or distress.

A pleural effusion is diagnosed by taking a medical history and doing a physical examination and chest x-ray. The chest x-ray will show if there is a collection of fluid around the lungs. If the cause of the effusion is unclear, a procedure called a thoracentesis (drainage of the fluid) may be done.

What happens in intensive care?

If someone has a large pleural effusion and shows deterioration in their respiratory function, they may be admitted to the intensive care unit (ICU). The length of time they need to spend in the ICU will depend on the cause of their pleural effusion and any other health problems they may have.

If their effusion is able to be drained, this may be done using either a needle inserted through the chest wall or an intercostal drain (a chest tube drain and water seal system). This procedure is done under a local anaesthetic.

People who suffer repeated effusions may need a procedure called chemical or surgical pleurodesis. This involves attaching the two pleural surfaces to each other so that fluid can no longer accumulate between them.

Useful links

Back to top