What is a sign of asthma?

• A. Bronchodilation
• B. Narrowing of airway
• C. Pneumothorax
• D. Mucus plugging

Answer: (B)

Airflow limitation in asthma comes from the airways becoming constricted, inflamed, and often producing extra mucus. The smooth muscle around the airways tightens (bronchoconstriction), the lining swells, and mucus can block the passage, all of which narrow the airways and make breathing harder. That narrowing is the clearest sign of an asthma episode.

Bronchodilation would widen the airways and relieve symptoms, so it’s not a sign of asthma. Pneumothorax is a different emergency (a collapsed lung) and isn’t characteristic of asthma. Mucus plugging can occur in asthma, but the defining change during an attack is the narrowing of the airways due to bronchoconstriction.