transudative

Transudative is a medical term used to describe fluids that accumulate in body cavities or tissues due to imbalances in hydrostatic and oncotic pressures, rather than inflammation. The fluid, or transudate, is typically clear, relatively low in protein, and contains few cells.

Causes and mechanism include reduced plasma oncotic pressure from hypoalbuminemia (as in nephrotic syndrome or cirrhosis) and increased hydrostatic pressure from fluid overload or congestive heart failure. Other etiologies are less common and may involve lymphatic obstruction or malnutrition. Transudates differ from exudates, which arise from inflammation or infection and are usually richer in protein and cells.

Diagnosis and characteristics: In pleural effusions, transudates generally do not meet Light’s criteria for exudates. Light’s criteria consider pleural fluid/serum protein ratio greater than 0.5, pleural fluid/serum LDH ratio greater than 0.6, or pleural fluid LDH more than two-thirds the upper limit of normal. Ascitic fluid in cirrhosis is typically low in protein. Transudates are usually low in cells and bacteria.

Clinical relevance and management: Management targets the underlying condition rather than the fluid itself. For heart failure, diuretics and sodium restriction may reduce fluid buildup; for cirrhosis or nephrotic syndrome, treatment aims at the primary disease and fluid balance. Recurrent effusions may require therapeutic drainage in selected cases, but prognosis depends largely on the associated disorder.