Serous- Exudative
TB and small cell lung cancer are 2 most common causes
'AIM for PE'
Autoimmune
Infection
Malignancy
Pulmonary embolus
Serous- Transudative
CCF
Renal failure
Hypoalbuminaemia from nephrotic syndrome, chronic liver disease, malnutrition
Non-serous
blood
pus
chyle