Abstract (243/250)
Objective: The potential benefit of a combined adenotonsillectomy and bronchoscopy with bronchoalveolar lavage (TA-B-BAL) in preschool children with asthma has been debated in the literature. We aimed to describe the clinical course of preschool children with severe asthma undergoing this combined procedure.
Study Design : This is a retrospective case-control study.
Patient Selection : Preschool patients diagnosed with severe asthma who underwent TA-B-BAL treatment between 2012 and 2019 were included as cases. Controls were age and sex matched patients receiving standard asthma care.
Methodology : A retrospective patient chart review was conducted. Data on demographics, clinical characteristics, medication use, virology and microbiology from bronchoalveolar lavage, and asthma control questionnaires were collected. Cases and controls were compared with t-tests and regression analysis.
Results: Eighteen preschool subjects (mean age 3.19±1.13 years) in the case group were matched to eighteen control subjects receiving standard care. A Poisson mixed effects regression analysis revealed reduced risk of oral corticosteroid use (RR 0.39, 95%CI 0.18, 0.83, p=0.014), reduced emergency department visits (RR 0.36, 95%CI 0.17, 0.75, p=0.01) and reduced risk of asthma exacerbations (RR 0.58, 95%CI 0.28, 1.20, p=0.14) in cases compared to controls. Ten patients experienced clinically meaningful improvements in TRACK scores after the procedure (p<0.001).
Conclusion: This pilot study provides early evidence that preschool children with severe asthma may benefit from combined adenotonsillectomy and bronchoscopy with bronchoalveolar lavage procedure. The procedure is a useful adjunct for reduction of medication use and hospital visits for preschool age patients with severe asthma.
Introduction
Asthma in the preschool period has a variable and unclear prognosis for remission, persistence and progression 1. Rather than a single disease, it is increasingly evident that asthma is a cluster of disorders, related by the presence of common symptoms of wheeze and cough 2. The heterogeneity in asthma reflects differences in the underlying biology and pathophysiology and therefore response to therapy. Comorbidities such as rhinitis, eczema, obstructive sleep apnea and obesity are associated with poor symptom control and may represent differences in underlying pathophysiology3-6. The preschool period is further complicated by a lack of objective measures to diagnose and monitor therapy contributing to sub-optimal asthma control. Consequently, preschool children suffer a disproportionate burden of morbidity in terms of exacerbations and hospitalizations 7. Several strategies aimed at reducing the burden of co-existing comorbidities show some promise in improving asthma control and may point to more precise treatments for preschool asthma 5,8,9.
Adenotonsillectomy (TA) is one of the most common surgical procedures performed in children to address adenotonsillar hypertrophy, obstructive sleep apnea, and recurrent infection and inflammation10-12. Studies exploring the effect of TA in asthmatic populations have revealed numerous benefits for symptom control and quality of life 8,9,11,13. Studies have noted a decrease in the need for respiratory medications post-operatively8,11,12 and an improvement in asthma symptoms5,9. Most notably, Saito et al. found 60% of pediatric patients were able to eliminate all of their medication and 28% were able to eliminate some of their medications post-operatively9. Clinically significant improvements in asthma control test scores have also been reported in the literature, associated with a significant decrease in emergency department visits, oral corticosteroid use 5, and limitation in activity in children following TA 11,13. The united airway concept may explain the link between upper airway inflammation and asthma 13,14. Persistent rhinovirus infection, for example, induces the release of multiple pro-inflammatory cytokines and, in turn, the proliferation of tonsillar lymphocytes14. Bacteria in the nasal passage, adenoids, and tonsils can similarly trigger inflammation of the lower airways15. Pharyngeal lymphoid tissue is the primary site for proliferation of viruses associated with wheezing 14. Furthermore, Kaditis, et al. concluded that children with a history of wheezing frequently have more tonsillar hypertrophy than those without wheezing 14. Bhattacharjee noted an association between airway inflammation, childhood obstructive sleep apnea (OSA) and severe asthma 8. These findings support the hypothesis that TA may have a role in the management of children with severe asthma16.
According to the American Thoracic Society guidelines for infants with recurrent or persistent wheezing, following treatment with bronchodilators, inhaled corticosteroids, or systemic steroids, a flexible fiberoptic bronchosopy and bronchoaleolar lavage is conditionally recommended 17. A bronchoscopy (B) can provide clinicians with important information regarding airway remodelling and anatomic abnormalities such as airway malacia or compression by vascular structures 17-19. Furthermore, in 20 case series, 40-60% of infants with recurrent wheezing had a positive bronchoalveolar lavage (BAL) culture 17. Patients who identify with lower airway infections, eosinophilia or neutrophilia can have improved symptoms with antibiotic therapy or other treatments 17. The potential benefits of a combined TA, bronchoscopy and bronchoalveolar lavage (TA-B-BAL) procedure on asthma control has not been previously reported.
The aim of this case-control study was to investigate the potential benefit of performing a combined TA, bronchoscopy and bronchoalveolar lavage procedure in a pediatric cohort of patients with preschool asthma.
Materials and Methods
This is a retrospective case-control study of children attending the asthma clinic at the Hospital for Sick Children, Toronto, Canada. The study was reviewed by the institutional Research Ethics Board at the Hospital for Sick Children (REB# 1000069481, April 19, 2020). Inclusion criteria for the cases were: 1. Children younger than 6 years at the baseline visit; 2. A diagnosis of preschool wheeze by a pediatric respirologist; 3. An assessment by a pediatric otolaryngologist; and 4. Treatment with a combined adenotonsillectomy and flexible bronchoscopy with bronchoalveolar lavage (TA-B-BAL) between 2012 and 2019. Patients were offered the TA-B-BAL procedure if they presented with adenotonsillary hypertrophy or history of recurrent infection. “Preschool asthma” was diagnosed in children by clinicians following the Canadian Thoracic Society guidelines 20. All children had a history of intermittent symptoms and documented response to inhaled bronchodilators.
All cases were matched one-to-one to a control subject followed in the same asthma clinic. Control subjects were diagnosed with preschool asthma by a pediatric respiratory medicine specialist, were treated with standard medical therapy and had no history of tonsillectomy or adenoidectomy. Matching was based on age at initial visit, sex, and time elapsed between visits. The study was designed to assess the effect of the TA-B-BAL procedure while accounting for the natural progression of asthma with age and standard medical therapy.
Data was retrospectively collected from the hospital charts at the following time points: initial assessment(s) in the severe asthma clinic; pre-operative consultation with the otolaryngologist; and at the first and second post-procedure assessments in the severe asthma clinic. Data collected included demographics, clinical characteristics, comorbidies and medication use. Asthma medications were categorized as inhaled corticosteroid monotherapy, leukotriene receptor antagonist (LTRA), long-acting beta2-agonist (LABA) and short-acting beta2-agonist (SABA). A detailed asthma history was also recorded, including the number of asthma exacerbations, oral corticosteroid courses prescribed, emergency department visits, and hospital and intensive care unit (ICU) admissions. Symptoms at baseline and during exacerbations were also collected when available. Finally, cytology and microbiology results from the BAL procedure were recorded (Figure 1) .