Pleural effusion, also called water on the lung, happens when fluid builds up in the space between your lungs and chest cavity. You may have symptoms, such as chest pain, depending on the cause. Thin ...

Empyema is defined as a collection of pus in the pleural space and is a form of purulent (infected), pleural effusion. Pleural effusion refers to the build-up of excess fluid between the layers of the ...