Exudative pleural effusion is associated with which mechanism?

Exudative pleural effusion is associated with which mechanism?

• A. Increased vascular permeability from infection or inflammation
• B. Decreased white blood cells
• C. Low LDH with normal protein
• D. Decreased protein content

Answer: (A)

Exudative pleural effusion results from inflammation that increases the permeability of pleural capillaries. When the pleura is inflamed, inflammatory mediators cause the vessels to become leaky, allowing protein-rich fluid and higher levels of LDH to seep into the pleural space. This produces a pleural fluid with higher protein and LDH relative to serum, characteristic of an exudate. In contrast, transudates arise from systemic pressure imbalances (like increased hydrostatic pressure or decreased oncotic pressure) and tend to have lower protein and LDH because the inflammation-driven leak is not the primary mechanism. So the best fit is the inflammatory-driven capillary leak that raises vascular permeability, not changes in white blood cell counts or simply low protein or LDH levels.

Exudative pleural effusion results from inflammation that increases the permeability of pleural capillaries. When the pleura is inflamed, inflammatory mediators cause the vessels to become leaky, allowing protein-rich fluid and higher levels of LDH to seep into the pleural space. This produces a pleural fluid with higher protein and LDH relative to serum, characteristic of an exudate. In contrast, transudates arise from systemic pressure imbalances (like increased hydrostatic pressure or decreased oncotic pressure) and tend to have lower protein and LDH because the inflammation-driven leak is not the primary mechanism. So the best fit is the inflammatory-driven capillary leak that raises vascular permeability, not changes in white blood cell counts or simply low protein or LDH levels.