Wheezing is most commonly caused by what physiological change?

• A. Infection
• B. Fluid overload
• C. Narrowing airway
• D. Muscle weakness

Answer: (C)

Wheezing arises mainly from narrowing of the airways. When the airways become constricted—whether from bronchoconstriction, inflammation, or excess mucus—the air must squeeze through a tighter passage. This creates turbulent flow that makes the airway walls vibrate, producing a high-pitched whistling sound, especially during exhalation.

Infections can trigger wheeze by causing inflammation or increased secretions, but the audible wheeze itself comes from narrowed airways rather than the infection alone. Fluid overload tends to produce crackles from fluid in the lungs, not the musical wheeze. Muscle weakness affects the strength of breathing but does not create the narrowed-airway sound.