Mechanisms of production of a pleural effusion
| Mechanism | Type of pleural effusion |
|---|---|
| Increased hydrostatic pressure in the capillaries of the visceral pleura | Transudate |
| Decrease in oncotic pressure in pleural capillaries | Transudate |
| Decrease in hydrostatic pressure in the pleural space | Transudate |
| Increased permeability of pleural capillaries | Exudate |
| Impaired lymphatic drainage of the pleural space | Exudate |
| Movement of fluid from the peritoneal space | Transudate/exudate Sometimes chylothorax |
| Thoracic duct injury | Chylothorax |
| Vascular rupture | Haemothorax |