Transudative Pleural Effusion

Chapter: Transudative Pleural Effusion
McMaster Section Editor(s): Nathan Hambly, Paul M. O’Byrne
Section Editor(s) in Interna Szczeklika: Ewa Niżankowska-Mogilnicka, Filip Mejza
McMaster Author(s): Amornpun Wongkarnjana, Nathan Hambly
Author(s) in Interna Szczeklika: Krzysztof Sładek, Miłosz Jankowski
Additional Information

Also see Pleural Effusion.

Definition and Etiology

Transudative pleural effusions accumulate in the pleural space as a result of increase in the hydrostatic pressure in the pleural capillaries (mainly in the parietal pleura), decrease in the osmotic or oncotic pressure, or less commonly as a result of fluid translocation from the peritoneal cavity.

A transudate is a clear pale-yellow fluid with low protein and lactate dehydrogenase (LDH) levels, pH usually >7.35, and low cell counts comprising mostly lymphocytes.

Causes: Heart failure, cirrhosis, mitral stenosis, diseases of the pericardium, pulmonary embolism (rare), hypothyroidism, hypoalbuminemia, nephrotic syndrome, peritoneal dialysis, and urinothorax (presence of urine in the pleural cavity due to retroperitoneal leakage of urinoma).


Treatment is limited to management of the underlying condition. In patients with cirrhosis and recurrent transudative pleural effusions, consider transjugular intrahepatic portosystemic shunt (TIPS).

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