Reviewed by Ellen Volker, MD, MSPH
Pleural effusion is often referred to as “fluid in the lungs” or “water on the lungs.” It is a buildup of excess pleural fluid in the chest cavity and the outside of the lungs. 

The inside your chest is lined with a thin membrane called the pleura. This membrane also lines the outside of your lungs. There is normally a small amount of fluid between these two spaces that keeps the lungs lubricated. Infection, irritation or inflammation can create excess fluid and cause pleural effusion.

Pleural effusion is common. More than 200,000 cases are diagnosed each year in the U.S.  The most common cause of pleural effusion is congestive heart failure. Other causes can include infection, cancer, chest trauma, tuberculosis, certain medications and cancer treatments.

Symptoms of pleural effusion can include chest pain, difficulty breathing and fever. Symptoms can be mild to severe.

Treating pleural effusion depends on the cause. First, treatment focuses on removing the extra fluid. Then it will treat the symptoms. Finally, treatment will work to prevent you developing pleural effusion again.

Pleural effusion can become complicated if the pleural fluid becomes infected or if the extra fluid places enough pressure on the lungs that they partially or fully collapse. Pleural effusion is treatable with proper medical attention and a healthy lifestyle.

Pleural effusion can include pleurisy, or inflammation of the pleura. Pleurisy is often caused by viral and bacterial infections. Symptoms can be uncomfortable and include sharp chest pain that worsens when breathing deeply, coughing or sneezing.


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