Up to 3 percent of all children are hospitalized with bronchiolitis (inflammation of the bronchioles, small airways in the lungs) in their first year of life. Despite the high prevalence of bronchiolitis, which is caused primarily by the respiratory syncytial virus (RSV), little consensus exists on the need for laboratory testing to diagnose the illness or optimal management of the disease. These issues are examined in two studies by the Research Triangle Institute/University of North Carolina Evidence-based Practice Center, which is supported by the Agency for Healthcare Research and Quality (contract 290-97-0011) and directed by Kathleen Lohr, Ph.D. The studies are summarized here.
Bordley, W.C., Viswanathan, M., King, V.J., and others (2004, February). "Diagnosis and testing in bronchiolitis: A systematic review." Archives of Pediatric and Adolescent Medicine 158, pp. 119-126.
Complete blood cell (CBC) counts and chest x-rays can be useful in children with unusual clinical courses or severe bronchiolitis. However, in most infants with bronchiolitis, the limited evidence available does not support routine use of testing for RSV, chest x-rays, or CBC counts, since they have not been shown to alter clinical outcome, concludes this study. The investigators conducted an extensive review of the literature on diagnostic and supportive testing in the management of bronchiolitis. Of the 797 abstracts identified, 82 trials met inclusion criteria for analysis.
Evidence from the studies indicates that the use of testing is typically justified to rule out other diagnoses (for example, bacterial pneumonia), for first-time wheezing, and for deciding on treatment. However the studies do not define clear indications for such testing or the impact of testing on relevant patient outcomes. For example, numerous studies found that rapid RSV tests had acceptable sensitivity and specificity, but no data showed that RSV testing affected clinical outcomes in typical cases of the disease.
In the 17 studies that presented chest-x-ray data, x-ray abnormalities in children with suspected bronchiolitis ranged from 20 to 96 percent. However, insufficient data exist to show that chest x-ray films reliably distinguish between viral and bacterial respiratory disease or predict severity of disease. In a similar vein, 10 studies included CBC counts, but most did not present specific results. Given the high prevalence of bronchiolitis, the investigators suggest prospective trials of diagnostic and supportive testing.
King, V.J., Viswanathan, M., Bordley, C., and others (2004, February). "Pharmacologic treatment of bronchiolitis in infants and children: A systematic review." Archives of Pediatric and Adolescent Medicine 158, pp. 127-137.
Bronchodilators and corticosteroids are commonly used to treat bronchiolitis in infants and children, but little consensus exists about optimal management strategies. This review of research on the topic conducted since 1980 included 44 studies of the most common bronchiolitis treatments. The studies presented no substantial evidence to support a routine role for epinephrine, beta-agonist bronchodilators, corticosteroids, or ribavirin in treating children with bronchiolitis.
However, the randomized controlled trials that met inclusion criteria were generally underpowered to detect significant outcome differences between study groups. Also, few studies collected data on outcomes that are of great importance to parents and clinicians, such as the need for and duration of hospitalization. The researchers call for a sufficiently large, well-designed pragmatic trial of the commonly used interventions for bronchiolitis to determine the most effective treatment strategies for managing the condition.