What is pleural effusion?

• A. Abnormal accumulation of fluid in the pleural space
• B. Infection of the lung's pleura
• C. Condition of excessive air in the pleural cavity
• D. Blockage of the thoracic duct

Answer: (A)

Pleural effusion refers to an abnormal accumulation of fluid in the pleural space, which is the thin fluid-filled cavity between the two pleurae (the membranes lining the thoracic cavity and surrounding the lungs). This condition can occur due to various underlying issues, including congestive heart failure, infections, malignancies, and inflammatory diseases. The buildup of fluid can impact lung function by restricting the expansion of the lungs during breathing, leading to symptoms such as shortness of breath, chest pain, and cough.

Other options describe different pulmonary or thoracic conditions. For instance, an infection of the lung's pleura would indicate pleuritis or pleurisy rather than pleural effusion, which specifically involves fluid accumulation. The condition of excessive air in the pleural cavity is known as pneumothorax, not pleural effusion. Lastly, a blockage of the thoracic duct relates to a lymphatic issue rather than a fluid accumulation specific to the pleural space. Each of these options addresses different physiological states, but the defining characteristic of pleural effusion is indeed the accumulation of fluid in the pleural space.