Which condition is a classic cause of increased pulmonary vascular hydrostatic pressure leading to pleural effusion?

Which condition is a classic cause of increased pulmonary vascular hydrostatic pressure leading to pleural effusion?

• A. Congestive heart failure
• B. Pancreatitis
• C. Hypoproteinemia
• D. Lymphatic obstruction

Answer: (A)

Elevated hydrostatic pressure in the pulmonary vessels pushes fluid out of capillaries into the pleural space, so pleural effusions form as transudates when the pressure gradient favors fluid leakage. Congestive heart failure is the classic scenario: when the heart fails on the left side, pressures build up in the left atrium and pulmonary veins, raising capillary hydrostatic pressure in the lungs. This drives fluid into the interstitial space and then into the pleural cavity, typically yielding a bilateral, low-protein transudate. Pancreatitis-related effusions arise mainly from inflammatory processes and enzyme-rich fluid, not from increased hydrostatic pressure. Hypoproteinemia lowers oncotic pressure, leading to edema and effusions via fluid loss from the vascular space rather than a primary rise in hydrostatic pressure. Lymphatic obstruction causes fluid accumulation by blocked drainage or chyle leakage, not by elevated hydrostatic pressure.

Elevated hydrostatic pressure in the pulmonary vessels pushes fluid out of capillaries into the pleural space, so pleural effusions form as transudates when the pressure gradient favors fluid leakage.

Congestive heart failure is the classic scenario: when the heart fails on the left side, pressures build up in the left atrium and pulmonary veins, raising capillary hydrostatic pressure in the lungs. This drives fluid into the interstitial space and then into the pleural cavity, typically yielding a bilateral, low-protein transudate.

Pancreatitis-related effusions arise mainly from inflammatory processes and enzyme-rich fluid, not from increased hydrostatic pressure. Hypoproteinemia lowers oncotic pressure, leading to edema and effusions via fluid loss from the vascular space rather than a primary rise in hydrostatic pressure. Lymphatic obstruction causes fluid accumulation by blocked drainage or chyle leakage, not by elevated hydrostatic pressure.