transudaten

Transudaten (transudates) are noninflammatory fluids that accumulate in body cavities or tissues due to systemic imbalances in hydrostatic and oncotic forces rather than local inflammatory processes. They typically have low protein content, low cellularity, and low lactate dehydrogenase (LDH) compared with exudates, and they are often clear or pale yellow in appearance.

Pathophysiology involves two main mechanisms: increased capillary hydrostatic pressure or decreased plasma oncotic (colloid) pressure. Conditions that raise hydrostatic pressure, such as congestive heart failure or venous obstruction, promote filtration of fluid into interstitial spaces or cavities. Conditions that lower oncotic pressure, such as hypoalbuminemia from nephrotic syndrome or liver cirrhosis, also favor transudate formation. The resulting fluid is usually sterile and contains little inflammatory cells.

Common clinical settings for transudates include pleural effusions, ascites, and pericardial effusions, as well as joint effusions in some contexts. Diagnostic evaluation focuses on fluid analysis and comparison with serum values. For pleural effusions, Light’s criteria help distinguish transudates from exudates: transudates typically do not meet the criteria (for example, pleural fluid to serum protein ratio generally remains below 0.5, and pleural LDH ratio below 0.6). In ascites, the serum-ascites albumin gradient (SAAG) of ≥1.1 g/dL indicates portal hypertension-related transudate.

Management centers on treating the underlying disorder. This may involve diuretics and salt restriction for fluid overload, management of heart failure, or treatment of liver or kidney disease. Drainage procedures (paracentesis or thoracentesis) may be employed for symptomatic relief. The prognosis depends primarily on the control of the underlying condition.