Pleural effusion overview

Overview
Pleural effusion is excess fluid that accumulates in the pleural cavity, the fluid-filled space that surrounds the lungs.

Four types of fluids can accumulate in the pleural space:
 * Serous fluid (hydrothorax)
 * Blood (hemothorax)
 * Chyle (chylothorax)
 * Pus (pyothorax or empyema)