Acute infant bronchiolitis; management and prognosis

Abstract

Acute bronchiolitis is a viral lower respiratory tract infection in infants. Few treatment options have been shown to reduce severity or shorten the duration of symptoms. Hospital management is therefore supportive. Based on knowledge gaps, the thesis aimed to identify risk factors for receiving supportive care for bronchiolitis, to determine the ability of parental and clinical assessment at hospitalisation to predict the short-term disease prognosis, and to explore if disease severity and/or early allergic sensitization, type or load of viruses or salivary cortisol during acute bronchiolitis in infancy increases the risk of asthma development. The Bronchiolitis ALL study, a multicentre trial, included 404 infants <12 months of age with acute bronchiolitis, and 240 infants as a general population-based control group. Information was obtained by structured interview, hospital chart entries, severity assessment by a clinical score and parental visual analogue scales and nasopharyngeal aspirates and serum for Immunoglobulin-E analyses at enrolment, followed by investigations at two years to determine the presence of asthma. The risk of receiving supportive care during hospitalisation included SpO2 < 92%, increased heart rate and lower age at the time of hospital admission and delivery by caesarean section. Parental evaluation outperformed the clinical score for predicting supportive care. Overall, 8.5% were sensitized, mostly to foods. Neither disease severity, allergic sensitisation, specific viruses, viral load nor salivary morning cortisol were associated with the risk of early asthma development in children hospitalised with acute bronchiolitis. The thesis highlights the importance to include parental evaluation of their infants with bronchiolitis in a structural clinical decision making. Asthma development may to a greater extent be linked to congenital risk factors than the severity of bronchiolitis, specific viruses and early allergic sensitisation.