Pleural effusion.

Causes...

Inlammatory:

Serofibrinous pleuritis

Collagen vascular disease

Suppurative pleuritis (empyema)

Hemorrhagic pleuritis : Tumor

Noninflammatory:

Hydrothorax : Transudate, eg Congestive heart failure

Hemothorax ,eg, aortic aneurysm, trauma

Chylothorax : Tumor obstructing normal lymphatics

Transudative effusion vs exudative effusion, and Light’s criteria( protein less than 50% of plasma, and LDH less than two third of plasma is labelled a transudate, else it is called an exudate).