Pleural effusion, sometimes referred to as “water on the lungs,” is the build-up of excess fluid between the layers of the pleura outside the lungs. The pleura are thin membranes that line the lungs and the inside of the chest cavity and act to lubricate and facilitate breathing.

What does pleural effusion indicate?

Pleural effusion, sometimes referred to as “water on the lungs,” is the build-up of excess fluid between the layers of the pleura outside the lungs. The pleura are thin membranes that line the lungs and the inside of the chest cavity and act to lubricate and facilitate breathing.

What happens if you have pleural effusion?

When you have a pleural effusion, fluid builds up in the space between the layers of your pleura. Normally, only teaspoons of watery fluid are in the pleural space, which allows your lungs to move smoothly in your chest cavity when you breathe.