In a patient with asthma presenting with shortness of breath, which lung sound is most likely to be heard?

• A. Rales
• B. Wheezes
• C. Rhonchi
• D. Stridor

Answer: (B)

Wheezes reflect airflow through narrowed airways, which is exactly what happens in an asthma attack. When the bronchioles constrict and swell, air must squeeze through these tight passages, producing a musical, high- or low-pitched sound as it moves. This is most noticeable during expiration when air moves more vigorously through the narrowed passages, though it can be heard on inspiration as well.

Rales (crackles) come from fluid in the small airways or surfaces of the lungs, not from bronchospasm, so they’re not the typical finding in asthma. Rhonchi are coarse rattling sounds from secretions in larger airways—possible in some respiratory conditions but not the hallmark of an asthma attack. Stridor is a harsh, vibrating sound from upper airway obstruction, such as swelling above the glottis, and points to a different issue altogether.

So the best answer is the wheeze, the classic sound of constricted airways in asthma. In severe cases, breath sounds can become faint or absent, but the presence of a wheeze most strongly indicates ongoing bronchospasm and guides use of bronchodilators.