MISUSE OF ANTIMICROBIALS IN CHILDREN WITH ASTHMA AND BRONCHIOLITIS: A REVIEW

Of 200 children hospitalized because of asthma or bronchiolitis, 100 received antibiotics inappropriately. Bronchiolitis is a clinical diagnosis consisting of the acute onset of wheezing, often associated with rhinorrhea, shortness of breath and mild to moderate respiratory distress. Respiratory syncytial virus (RSV) is the principal etiologic agent. 1, 2 Chest radiography is deceptive, in that it may be normal or reveal hyperinflation, atelectasis or frank infiltrates. 2 The PICNIC group (Pediatric Investigators Collaborative Network on Infection in Canada), in their prospective study on risk factors and management of RSV lower respiratory tract infections across Canada, revealed that 57 to 81% of infants with this diagnosis receive antibiotics, 3 despite the fact that antibiotics have been shown to be of no benefit in the treatment of bronchiolitis. 4 In addition there is evidence that RSV infection does not predispose to bacterial superinfection, regardless of radiographic findings. 5 Asthma is defined as reversible, recurrent episodes of airway hyperreactivity. It is the most common chronic respiratory illness in childhood. In the recent Asthma Education and Prevention Program Guidelines, antibiotic therapy is not recommended as a routine therapeutic measure. 6 It has been suggested that the use of antibiotics in the management of asthmatic patients is on a downward slope 7; however, very few studies address this issue thoroughly and no convincing data exists to confirm this. The purpose of this retrospective analysis was to assess whether the data confirming that antibiotic therapy is not warranted in both bronchiolitis and asthma have modified the practice of pediatricians in a tertiary care pediatric center. Methods. Patient population. Children admitted to The Montreal Children’s Hospital (a tertiary care pediatric center staffed almost exclusively by pediatricians), from November, 1997, to February, 1998, were considered eligible if they had either an admitting or discharge diagnosis of asthma or bronchiolitis. A total of 202 cases were identified. Data collection/analysis. Data were collected by means of a chart review. The information was initially transcribed to a computer spreadsheet program, Epi 6.0. For statistical analysis the data were converted to an SPSS program format. Analysis included standard descriptive statistics. Results. Of the 202 cases considered for the study 200 were retained. Two cases were excluded because charting was inadequate to properly assess therapeutic management. Ages ranged from 3 weeks to 20 years of age (mean age, 3.3 years). Thirty-six patients (18.0%) were given a diagnosis of bronchiolitis, and 141 patients (70.5%) were diagnosed as asthmatic. One patient carried both diagnoses simultaneously, and 22 of the 200 patients (11.0%) had a questionable diagnosis of either bronchiolitis or asthma. Thirty of the 200 children (15%) had antibiotics prescribed before admission (Fig. 1). Six of these patients had no clear diagnosis to justify the use of antibiotics. In those cases in which a reason was identified, upper respiratory tract bacterial superinfections accounted for the majority. Twelve children (40%) were diagnosed with otitis media, and 4 of 30 cases (13.3%) were diagnosed with sinusitis. The clinical diagnosis of pneumonia (without radiographic proof) was made in another 5 cases (16.6%). The remainder (3 patients) were receiving antibiotics for unrelated reasons.Fig. 1: Antibiotic use in children with respiratory infections. E.R., emergency room;R/O, rule out.In the hospital an additional 70 patients were prescribed antimicrobials by pediatricians working in the emergency room, bringing the total number of children receiving antibiotics to 100 (50%). The reasons for antibiotic therapy are outlined in Figure 1. Forty-nine (70%) of the 70 patients were given antibiotics for presumed bacterial pneumonia. Fifty-seven of the 70 patients given antibiotics in hospital remained on antibiotics at the time of discharge. The diagnoses of pneumonia were reviewed during hospitalization and subsequently discounted in 9 of the 13 patients who discontinued antibiotic therapy. In another 2 cases a diagnosis of otitis media was refuted based on lack of clinical findings. Two of the 13 patients were given parenteral antibiotics for suspected sepsis, with discontinuation of antimicrobial therapy when no bacterial focus of infection was identified. Specific criteria were established to define each diagnosis. Each case was then studied individually to assess whether sufficient data in the chart supported the use of antibiotics. Antibiotic use for the diagnosis of pneumonia was considered appropriate when viral studies (which consisted of immunofluorescence and viral cultures of a nasopharyngeal sample) were negative, in addition to a positive reading by a pediatric radiologist of a chest radiograph. Interpretations of the chest radiograph consistent with “infiltration” or “cannot rule out pneumonia” were accepted. When viral studies were not performed but chest radiograph readings were positive for the presence of an infiltrate, the patients were considered to have received antibiotics appropriately. It is likely that the majority of these children had viral pneumonitis, but for the purposes of this analysis we considered the use of antimicrobials as appropriate, given that proof of this hypothesis was lacking. A diagnosis of otitis media was considered accurate when there was documented evidence of a red tympanic membrane, with or without bulging, or frank purulent discharge from the tympanic membrane. The appropriateness of this diagnosis when made by an outside physician before admission could not be assessed and was therefore assumed adequate for the purposes of this study. The use of antibiotics in the diagnosis of sinusitis was accepted as appropriate when the diagnosis was made on clinical grounds (>10 days of purulent nasal discharge, with or without sinus tenderness or facial pain). Corroborating radiographic evidence was not mandatory. Of the 200 cases considered in this analysis, antibiotics were included in the management of 100 cases. The use of antimicrobials was deemed unjustified by our established criteria in 34 cases (34.0%). Of the patients given antibiotics by an outside physician for pneumonia, only 1 of 5 patients had an abnormal chest radiograph. In addition, of the 49 patients given an in-hospital diagnosis of pneumonia, 22 of 49 had a normal chest radiograph. Thus a total of 26 of 34 (76.5%) patients were misdiagnosed with pneumonia (4 of whom were also misdiagnosed with otitis media). Four (11.8%) of the 34 patients were given antibiotics for possible otitis media, when there was no documented evidence of an abnormal tympanic membrane or middle ear fluid. Two of the 6 patients treated with antibiotics without clear justification by an outside physician had their antibiotics discontinued in hospital when no bacterial infection was identified. One patient was given antibiotics with no documented justification in the emergency room, with subsequent discontinuation of therapy while hospitalized. Furthermore in the 66 patients deemed to have received antibiotics appropriately, some patients received diagnoses of both pneumonia and otitis media. Five such patients had no evidence to support the diagnosis of pneumonia. These 5 cases of pneumonia misdiagnosis are not included in the analysis of inappropriate antibiotic use. Discussion. In this retrospective review of children admitted with the diagnoses of asthma and bronchiolitis to a tertiary care pediatric hospital, one-half of the children were prescribed antimicrobials. Of those, one-third received antibiotics with no documented evidence supporting a focus of bacterial infection. Up to 75.8% of these children given antibiotics had misdiagnosed bacterial pneumonia. In addition, as stated above, the use of antimicrobials for bacterial pneumonia in 5 of the 66 patients considered to have received antibiotics appropriately may be questioned. Furthermore in 27 of the 66 cases no viral studies were performed and very well may have been positive. Six of these patients were given a clinical diagnosis of bronchiolitis, while 21 cases were diagnosed with asthma. Given the low probability of bacterial superinfection in the context of a clinical diagnosis of bronchiolitis, these 6 patients would likely not have warranted antimicrobial therapy. These 6 cases, along with the 5 pneumonia misdiagnosis cases, suggest that the number of patients with questionable indications for antimicrobial therapy could be as many as 44 of 100 (44.0%). These figures may reflect the discomfort of pediatricians to attribute abnormal radiographic findings to a viral pathogen, in the presence of bronchiolitis and asthma, despite evidence in the medical literature that antibiotics offer no benefit in this context. 4–6 Other diagnoses contributing to the illegitimate use of antibiotics included misdiagnoses of acute otitis media, undocumented indications and diagnoses made by physicians in the community that could not be confirmed when in hospital. The high rate of antibiotic use in the absence of true bacterial infection in this population is concerning, given the fairly common nature of asthma and bronchiolitis in a pediatric population. Similar statistics have been demonstrated in other studies. 3, 8 The inherent limitations of a retrospective chart analysis, as well as the small number of cases in this study, do not undermine the obvious trend in antibiotic misuse. The excessive and often inappropriate use of antibiotics has been repeatedly shown to promote the development of resistant organisms. 9, 10 In an era of evidence-based medicine, this study shows that pediatricians have been reluctant to adhere to well-established evidence against the use of antibiotics in illnesses in which antimicrobials have no benefit. The magnitude of inappropriate antibiotic prescription in asthmatic and bronchiolitic children would be better assessed with a prospective study, especially one that is community-based, given that only 1% of children infected with RSV bronchiolitis require hospitalization. 11 Similarly most asthma therapy is managed within the community. It is likely that the figures would be at least equal to those generated in this study. Previous data suggest that community physicians prescribe antibiotics to 44% of children with the common cold, 46% of children presenting with an upper respiratory tract infection and 75% of children with bronchitis. 12 Should this be the case a strong impetus for generating stricter guidelines for the work-up and management of such patients, as previously suggested, 8 may be of benefit to patients in general and to the health care system as a whole. Acknowledgments. We thank Rick Jane, of the Montreal Children’s Hospital’s Clinical Research Laboratory, whose assistance in statistical design and analysis was indispensable to this project.

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