Viral bronchiolitis

Abstract

Viral bronchiolitis is a common clinical syndrome affecting infants and young children. Concern about its associated morbidity and cost has led to a large body of research that has been summarised in systematic reviews and integrated into clinical practice guidelines in several countries. The evidence and guideline recommendations consistently support a clinical diagnosis with the limited role for diagnostic testing for children presenting with the typical clinical syndrome of viral upper respiratory infection progressing to the lower respiratory tract. Management is largely supportive, focusing on maintaining oxygenation and hydration of the patient. Evidence suggests no benefit from bronchodilator or corticosteroid use in infants with a first episode of bronchiolitis. Evidence for other treatments such as hypertonic saline is evolving but not clearly defined yet. For infants with severe disease, the insufficient available data suggest a role for high-flow nasal cannula and continuous positive airway pressure use in a monitored setting to prevent respiratory failure.

Figure 1

Typical clinical course and pathophysiology of viral bronchiolitis

Figure 2

Meta-analysis of studies assessing average clinical score after treatment in patients with bronchiolitis receiving bronchodilators versus placebo Test for heterogeneity in the inpatient studies demonstrated low inconsistency between the nine studies (I²=36%; p=0·13) and the summary effect was not significant (Z=1·06; p=0·29), the outpatient studies demonstrated very high inconsistency between the 12 studies (I²=81%; p<0·00001) and the summary effect was significant (Z=2·26; p=0·024), and the overall heterogeneity of the meta-analysis demonstrated high inconsistency between the 21 studies (I²=73%; p<0·00001) and the overall summary effect was significant (Z=2·4; p=0·016). IPR=ipratropium. SAL=salbutamol. neb=nebulised. Reproduced from Gadomski and Scribani, by permission of John Wiley and Sons.

Figure 3

Meta-analysis of studies assessing hospital length of stay in patients with bronchiolitis receiving nebulised 3% hypertonic saline versus control Significant difference in length of hospital stay was found in those receiving hypertonic saline compared with control; however, the largest trials had negative results, making it challenging to provide definitive conclusions regarding use of hypertonic saline in bronchiolitis. Reproduced from Maguire and colleagues, under the CC BY 4.0 Creative Commons license: http://creativecommons.org/licenses/by/4.0/.

Figure 4

Meta-analysis of studies assessing admission to hospital on day 1 and day 7 in patients with bronchiolitis receiving corticosteroids versus placebo Test for heterogeneity in studies assessing admission at day 1 demonstrated very low inconsistency between the ten studies (I²=0%; p=0·55) and the summary effect was not significant (Z=1·05; p=0·30), and studies assessing admission at day 7 demonstrated low inconsistency between the six studies (I²=32%; p=0·21) and the summary effect was not significant (Z=1·38; p=0·17). G=glucocorticoid. P=placebo. S=salbutamol. E=epinephrine. Reproduced from Fernandes and colleagues, by permission of John Wiley and Sons.