bronchiolitis
Inflammation of the small airways in infants and young children, most commonly caused by respiratory syncytial virus (RSV).
Full Definition
Bronchiolitis is an acute inflammatory condition of the bronchioles, the smallest airways in the lungs, primarily affecting infants and children under 2 years of age. Respiratory syncytial virus (RSV) is the most common causative agent, accounting for approximately 70% of cases, though human metapneumovirus, parainfluenza virus, rhinovirus, and adenovirus can also cause the condition. The inflammation leads to bronchiolar edema, increased mucus production, and potential airway obstruction, resulting in wheezing, increased work of breathing, and hypoxemia. Clinical presentation includes cough, rhinorrhea, low-grade fever, and progressive respiratory distress with retractions, nasal flaring, and decreased feeding. Most cases are managed supportively with supplemental oxygen if needed, though severe cases may require hospitalization and respiratory support.
Usage
Usage note: Distinguish from pneumonia by noting the small airway involvement and typical age group affected.
In Context
- "The infant's bronchiolitis required supplemental oxygen to maintain adequate saturation levels." — pediatric hospitalist progress note
- "Peak bronchiolitis season occurs during winter months when RSV circulation is highest." — pediatric pulmonology clinic documentation