A pleural effusion 肋膜積水 (肺積水) is an unusual amount of fluid around the lung.
Many medical conditions can lead to it, so even though your pleural effusion may have to be drained, your doctor likely will target the treatment at whatever caused it.
The pleura is a thin membrane that lines the surface of your lungs and the inside of your chest wall. 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.