What condition is characterized by lower respiratory tract infection of the small airways leading to obstruction?

Acute bronchiolitis is characterized by a lower respiratory tract infection that primarily affects the small airways (bronchioles) in the lungs, leading to obstruction. This condition is most commonly seen in infants and young children, often triggered by viral infections, particularly respiratory syncytial virus (RSV).

The obstruction occurs due to inflammation, mucus production, and swelling of the airway walls, which impedes airflow and can result in difficulty breathing, wheezing, and hypoxia. Unlike conditions such as pneumonia, which involves the lung parenchyma leading to consolidation and is often associated with fever and cough, or asthma, which is primarily an inflammatory condition leading to airway hyperreactivity, bronchiolitis specifically affects the small airways and is most prevalent in a younger population.

In bronchitis, inflammation affects the larger airways rather than the bronchioles and typically presents in older children and adults as a persistent cough with production of sputum. Understanding the specific characteristics and mechanisms of these conditions helps in diagnosing and managing respiratory illnesses effectively, particularly in pediatric patients.