(Water on the Lungs)
by Cynthia M. Johnson, MA
Pleural effusion is a buildup of fluid in the pleura. The pleura are the two thin, moist membranes around the lungs. They let the lungs expand and contract.
The cause is usually disease or injury. Common causes are:
Things that may raise the risk of this problem are:
Some people may not have symptoms. Others may have:
The doctor will ask about your symptoms and health history. A physical exam will be done. This may include listening to or tapping on your chest.
A lung function tests will be done. It can show how well air is moving in and out of the lungs.
Blood tests may be done based on what the doctor thinks it causing the fluid.
Pictures may be taken of the lungs. This can be done with:
Samples of the fluid or pleura may be taken for testing. This can be done with:
Treatment depends on what is causing the problem. It may include:
People who are not helped by other methods may need surgery. Some of the pleura will be removed.
Manage health problems that may lead to effusion.
American Lung Association
National Heart, Lung, and Blood Institute
Pleural effusion. EBSCO DynaMed website. Available at: https://www.dynamed.com/approach-to/pleural-effusion. Accessed November 25, 2020.
Pleural effusion. Merck Manual Professional Version website. Available at:
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Accessed November 25, 2020.
Saguil A, Wyrick K, et al. Diagnostic approach to pleural effusion. Am Fam Physician. 2014 Jul 15;90(2):99-104.
Last reviewed September 2020 by EBSCO Medical Review Board Marcin Chwistek, MD