A 3-month-old infant presents in winter with a 2-day history of rhinorrhoea followed by progressively worsening wheeze, subcostal and intercostal retractions, respiratory rate 72/min, and SpO2 88% on room air. The most common causative organism is:

• A Parainfluenza virus type 3
• B Human metapneumovirus
• C Respiratory syncytial virus (RSV) ✓
• D Influenza A

Explanation

Respiratory syncytial virus (RSV) is the most common cause of acute bronchiolitis in infants under 2 years of age, accounting for 50–80% of cases. It has a seasonal winter/spring predilection. Bronchiolitis presents with tachypnoea, wheeze, subcostal retractions, and hyperinflation after an upper respiratory prodrome. Parainfluenza type 3 is the second most common cause. Human metapneumovirus is third. Management is supportive (oxygen, fluid management); bronchodilators and steroids are not routinely recommended. Palivizumab prophylaxis is available for high-risk premature infants.

Reference: Ghai Essential Pediatrics, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.