What term describes escape of fluid into the pleural cavity?

• A. Croup
• B. Embolism
• C. Pneumothorax
• D. Pleural Effusion

Answer: (D)

Pleural effusion is the term for fluid accumulating in the pleural cavity. The pleural space normally contains only a small amount of lubricating fluid between the visceral and parietal pleura; when fluid builds up—due to heart failure, infection, malignancy, or inflammation—it enlarges the space and can compress the lung, leading to shortness of breath and chest discomfort. On exam or imaging, you may see dullness to percussion and blunted costophrenic angles on X-ray. This is different from a pneumothorax, which involves air in the pleural space, while croup and embolism refer to airway inflammation and vascular blockage, not fluid collection in the pleural space.