Acute bronchiolitis is the most common lower respiratory tract disease in infancy and the leading cause of hospitalization in children under two years of age. Many authors emphasize the importance of viral agents for the clinical course of the disease. This study aimed to assess the clinical severity of acute bronchiolitis in hospitalized infants. We examined 49 hospitalized children between 1 month and 2 years with acute bronchiolitis. The study investigated viral aetiology and markers of inflammatory activity. Disease severity was assessed according to the ReSVinet scale. A viral agent was identified in 59.2% of cases, with RSV (respiratory syncytial virus) as the predominant aetiology in 32.7%, followed by rhinovirus in 14.0%, human metapneumovirus and Bocavirus in 4.1% each, and Adenovirus, Influenza type A, and Parainfluenza virus in 1 (2.0%) each. No causative agent was identified in 40.8% of cases. We observed a mild clinical course in 30.6%, mostly with combined viral infection; a moderate course in 61.2%, mainly with RSV aetiology; and a severe course in 8.2%, in which no predominant etiological factor was identified. Further investigations are needed to clarify the relationship between viral aetiology and disease severity.

Acute bronchiolitis, ReSVinet scale, viral infection