Pleural friction rub is described as a grating sound indicating pneumonia; which option best captures this?

• A. Pneumonia
• B. Asthma
• C. Pulmonary edema
• D. Pleural effusion

Answer: (A)

Pleural friction rub appears when inflamed pleural surfaces rub together during breathing, producing a rough, grating sound. This finding points to pleuritis and is commonly seen with pneumonia that involves the pleura. Asthma mainly causes airway wheezing and doesn’t produce a friction rub. Pulmonary edema leads to crackles from fluid in the airspaces rather than a pleural rubbing sound. Pleural effusion can dull or decreased breath sounds, and a friction rub isn’t its defining feature unless pleuritis is also present, which is less specific. So, the description most closely aligns with pneumonia because pleural involvement from infection best explains the grating sound.