Pleural effusion in critically ill patients and intensive care setting

Table 1 Causes of transudative and exudative pleural effusions

Causes of transudative pleural fluid	Causes of exudative pleural fluid
Increased hydrostatic pressure: Congestive heart failure; constrictive pericarditis; pericardial effusion; massive pulmonary embolism; constrictive cardiomyopathy; pulmonary veno-occlusive disease	Infections: Parapneumonic effusion; complication of lung abscess; acquired immune deficiency syndrome; tuberculosis; fungal and actinomycotic disease; hantavirus syndrome; subphrenic abscess; hepatic amoebiasis
Reduced capillary oncotic pressure: Liver cirrhosis (hepatic hydrothorax); nephrotic syndrome; protein-losing enteropathy; malnutrition; small bowel disease	Neoplasm: Mesothelioma; metastasis; lymphoma; Meigs syndrome; rare tumors such as pleural sarcoma
Transmission from peritoneum: All causes of ascites; peritoneal dialysis; liver transplantation; ventriculoperitoneal shunt	Connective tissue diseases and immune disorders: Rheumatoid disease; systemic lupus erythematosus; post-myocardial infarction/cardiotomy syndrome; churg-Strauss syndrome; Wegener’s granulomatosis; rheumatic fever; Behcet syndrome; lymphangioleiomyomatosis
Increased capillary permeability: Small pulmonary emboli; myxoedema
Obstructed lung lymphatics: Lung transplantation	Abdominal diseases: Pancreatitis and pancreatic-pleural fistula. uraemia; other causes of peritoneal exudates
Others: Urinothorax; cerebrospinal fluid leakage into the pleura; trapped lung; central venous catheter migration	Others: Pulmonary embolism, sarcoidosis, drug reactions, radiation exposure, asbestos exposure, recurrent polyserositis, yellow nails syndrome, oesophageal rupture, superior vena cava syndrome, endometriosis, amyloidosis, extra-medullary hematopoiesis