Which term is defined as a viral infection commonly affecting the small airways in infants?

• A. RSV
• B. Croup
• C. Bronchiolitis
• D. Epiglottitis

Answer: (C)

Bronchiolitis is a viral infection that chiefly involves the bronchioles, the smallest airways in the lungs. In infants these tiny passages are easily obstructed by inflammation and mucus, so airflow is reduced and breathing becomes rapid and labored, often with wheezing and chest retractions. The most common cause is respiratory syncytial virus, which is why bronchiolitis is a classic illness of the first year of life. This focus on the small airways helps distinguish it from other pediatric airway conditions: croup is an upper airway illness (larynx/trachea) that tends to produce a barking cough and sometimes inspiratory stridor, while epiglottitis presents with a sudden onset, high fever, drooling, and a appearing anxious child with potential supraglottic obstruction. Because the issue lies in the small airways and mucus production, treatment is primarily supportive—ensuring adequate hydration and oxygenation, with more intensive care reserved for severe cases.