Clinical question: What are the rates of serious bacterial infection (SBI) in infants with bronchiolitis?
Background: Fever is common in young infants with viral bronchiolitis. Infants younger than 90 days of age with clinical bronchiolitis and fever often are evaluated according to established guidelines for fever without source. The extent to which this work-up is necessary remains unclear, as rates for bacteremia, urinary tract infections (UTIs), and meningitis have not been precisely defined in this population.
Study design: Systematic review of the literature.
Synopsis: After a Medline database search including the terms serious bacterial infection, bacteremia, meningitis, urinary tract infection, bronchiolitis, and respiratory syncytial virus (RSV), studies and bibliographies were screened for articles that allowed for a calculation of site- and age-specific rates of SBI. Studies based in ICUs and studies of pneumonia were excluded. Eleven studies were analyzed.
The prevalence rate for UTI was 3.3% based on a random effects meta-analysis. Study design and setting did not appear to influence this rate; however, the prevalence of UTI was higher in RSV-positive infants as opposed to infants with clinical bronchiolitis. Rates for bacteremia were very low, and there were no reported cases of meningitis.
This study provides useful information to guide clinical decision-making in the setting of a young, febrile infant presenting with bronchiolitis. Nonselective work-up for SBI appeared to be routine in the studies reviewed; the yield of work-up for bacteremia was extremely low (and zero for meningitis). Thus, investigations of blood and cerebrospinal fluid might be unnecessary in the uncomplicated patient.
Although it appears that UTIs do occur with reasonable frequency in this population, a primary limitation of the review is that the studies analyzed primarily used urine culture as a means of diagnosis without publication of urinalysis results. This increases the likelihood that UTI rates are overestimated in this population, as asymptomatic bacteriuria is a potential confounder.
Bottom line: Serious bacterial infection is rare in febrile young infants with bronchiolitis.
Citation: Ralston S, Hill V, Waters A. Occult serious bacterial infection in infants younger than 60 to 90 days with bronchiolitis: a systematic review. Arch Pediatr Adolesc Med. 2011;165(10):951-956.
Reviewed by Pediatric Editor Mark Shen, MD, FHM, medical director of hospital medicine at Dell Children’s Medical Center, Austin, Texas.