What characterizes transudative pleural effusion?

• A. High protein content
• B. Problem related to heart failure with watery fluid
• C. Presence of pus in the pleural space
• D. Composed primarily of red blood cells

Answer: (B)

Transudative pleural effusion is characterized by the accumulation of fluid in the pleural space due to imbalances in hydrostatic and oncotic pressures, rather than by direct injury or inflammation of the pleura. This type of effusion often develops in conditions such as congestive heart failure, where increased hydrostatic pressure leads to a watery fluid accumulation. The fluid is generally clear and low in protein content, which distinguishes transudative effusions from exudative types, where there is a higher protein concentration due to inflammation or injury.

The other choices do not accurately describe transudative pleural effusions. High protein content is indicative of exudative effusions. The presence of pus in the pleural space is associated with empyema, a type of exudative effusion due to infection. Composed primarily of red blood cells would suggest a hemothorax or trauma-related effusion rather than the clear fluid characteristic of transudation. Thus, the defining trait of transudative pleural effusion is its association with conditions like heart failure, leading to the accumulation of watery fluid in the pleural space.