Which statement best describes empyema?

• A. Fibrosis of lung parenchyma.
• B. Mucus buildup in nasal cavity.
• C. Edema of peripheral tissues.
• D. Pus in pleural space.

Answer: (D)

Empyema is pus in the pleural space—the cavity between the lungs and the chest wall. It occurs when an infection, such as pneumonia or a lung abscess, spreads to the pleura and the fluid becomes purulent. This leads to symptoms like fever and shortness of breath and often requires drainage plus antibiotics. The other descriptions refer to different issues: fibrosis is scarring of lung tissue, mucus buildup in the nasal cavity is rhinitis or sinusitis, and edema of peripheral tissues is swelling in the body's extremities. Therefore, describing pus in the pleural space best matches empyema.