Current Management of Acute Bronchiolitis: An Evidence-Based Approach
Not only the most common viral lower respiratory tract infection in children younger than age 2 years, bronchiolitis is a condition in which the diagnosis is based almost exclusively on history and physical examination.
Diagnosis
In 2014, the AAP updated its guidelines on the diagnosis, management, and prevention of bronchiolitis. One of the strongest statements in these guidelines emphasize that the diagnosis of bronchiolitis should be based almost exclusively on the history and physical examination.2 In children younger than age 2 years, historical features such as a viral prodrome, followed by progressively worsening increased respiratory effort and signs and symptoms of lower respiratory-tract disease (eg, wheezing), should guide clinicians to the diagnosis of bronchiolitis. Although nonspecific, physical examination findings such as rhinorrhea, cough, tachypnea, wheezing, rales, and increased respiratory effort—when coupled with a good history—can be beneficial in the diagnosis of bronchiolitis.
Pulse Oximetry
Pulse oximetry has become a standard part of the clinical assessment of patients with bronchiolitis. This is based on data suggesting that pulse oximetry detects hypoxia in cases where it was not suspected on physical examination alone.7 However, the effectiveness of pulse oximetry in predicting clinical outcomes is limited. Pulse oximetry should not be used as a proxy for respiratory distress, as studies have shown poor correlation between respiratory distress and oxygen saturations in infants with lower respiratory tract infection.8
Radiographic Evaluation
Regarding the diagnosis of bronchiolitis, the AAP notes, “radiographic and laboratory studies should not be obtained routinely.”2 While many children with bronchiolitis may have abnormalities on radiographs, there is insufficient data to suggest that chest radiographs correlate with disease severity. In addition, several studies, including a prospective cohort study by Schuh et al,9 have shown that infants with suspected lower respiratory tract infections who undergo radiography are more likely to receive antibiotics without any difference in outcomes.
Laboratory Studies
As stated in the AAP guidelines, routine laboratory testing, particularly virologic studies for RSV, have little role in the diagnosis of bronchiolitis. Since numerous viruses can cause bronchiolitis and have similar clinical presentations, the absence of identification of a particular virologic agent does not exclude the diagnosis of bronchiolitis and is moreover unlikely to alter management.
Although routine laboratory evaluation is not recommended in infants with bronchiolitis, one subgroup in which it may be beneficial is in the assessment of serious bacterial infections (SBIs) in febrile infants with bronchiolitis who are younger than 60 days old. Levine et al10 conducted a large, multicenter, prospective, cross-sectional study of young, febrile infants to determine the risk of SBI in those with RSV bronchiolitis versus those without RSV bronchiolitis. They found that overall febrile infants younger than age 60 days with RSV bronchiolitis have a lower rate of SBI than those without RSV (7% v 12.5%, respectively).10 In infants between age 28 and 60 days with RSV bronchiolitis, the origin of all SBIs in the study were urinary tract infections. In patients younger than 28 days of age, the risk of developing an SBI was found to be no different between the RSV-positive and RSV-negative groups.10
Based on the findings in this study, it is recommended that, at the very least, urinalysis for bacterial infection be performed in all infants with RSV bronchiolitis who are younger than age 60 days. Furthermore, since there was no difference in the rates of SBI in patients younger than age 28 days, infants in this age range should undergo a full septic work-up (blood, urine, and cerebrospinal fluid)—regardless of RSV infection status. For infants between ages 28 and 60 days, there is not enough evidence to recommend for or against further laboratory evaluation other than urinalysis.
Treatment
Nasal Suctioning
Nasal suctioning has become the first-line treatment for infants with bronchiolitis. It is used to clear secretions from the nasal passages to aid in respiration, which is particularly important in younger infants—who are obligate nose breathers. Current recommendations are to perform suctioning with increasing respiratory effort, before feeding and before laying the infant down to sleep.1
Bronchodilators
In the past, bronchodilators such as the β-agonist albuterol have been used to treat bronchiolitis with the idea that bronchial smooth muscle relaxation would improve clinical symptoms. In its 2006 guidelines, the AAP had recommended a trial of albuterol and continuation only if there was a documented objective response. In the 2014 updated guidelines, however, the AAP no longer recommends the use of albuterol in any capacity.
Although several meta-analyses and systematic reviews have demonstrated that bronchodilators may improve clinical symptoms scores, they did not affect disease resolution, need for hospitalization, or length of hospital stay.2 In addition, a recent Cochrane systematic review noted no benefit in the clinical course of infants with bronchiolitis treated with bronchodilators, and cited the potential adverse events (tachycardia and tremors) as outweighing any potential benefit.11 In addition to albuterol, the AAP no longer recommends the use of nebulized epinephrine in the treatment of bronchiolitis.2
