What causes empyema?
Empyema is usually caused by an infection that spreads from the lung. It leads to a buildup of pus in the pleural space.
There can be a pint or more of infected fluid. This fluid puts pressure on the lungs.
Risk factors include:
Bacterial pneumonia Chest surgery Lung abscess Trauma or injury to the chest
In rare cases, empyema can occur after a needle is inserted through the chest wall to draw off fluid in the pleural space for medical diagnosis or treatment (thoracentesis).