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Viral Determinants of Childhood Asthma Exacerbation Severity and Treatment Response
Nidhya Navanandan1, Nathan D Jackson2, Katharine L Hamlington3
1Section of Emergency Medicine, Department of Pediatrics, Children's Hospital Colorado, University of Colorado, Aurora, Colo.
Insights
Viral species significantly impact pediatric asthma exacerbations in the emergency department. Rhinovirus A infections were linked to milder cases, while enterovirus D68 caused more severe asthma attacks.
Area of Science:
- Pediatric Emergency Medicine
- Infectious Diseases
- Respiratory Medicine
Background:
- Respiratory viruses commonly trigger asthma exacerbations in children.
- The specific impact of viral infection characteristics on pediatric asthma presentation and treatment response in emergency departments remains unclear.
Purpose of the Study:
- To investigate viral infection characteristics in children with emergency department asthma exacerbations.
- To determine the association between viral factors, exacerbation severity, and treatment outcomes.
Main Methods:
- Prospective study of 107 children (4-18 years) treated for asthma exacerbations.
- Viral metagenomic analysis of nasal swabs to identify virus presence, load, and species.
- Assessment of exacerbation severity using Pediatric Asthma Severity (PAS) scores, clinical impression, and vital signs; treatment response defined by discharge without additional therapies.
Main Results:
- 86% of analyzed samples (73 children) detected viruses, with Rhinovirus A (RV-A), RV-C, and Enterovirus D68 being most common.
- RV-A associated with milder exacerbations (OR=0.25) and better treatment response.
- Enterovirus D68 linked to more severe exacerbations (OR=8.3) with no significant treatment response association. Viral load correlated with vital signs indicating severity.
Conclusions:
- Viral species significantly influence the severity and treatment response of pediatric asthma exacerbations.
- Early pathogen identification may guide emergency department treatment strategies.
- Further research is needed to understand the pathobiology of virus-specific exacerbations and optimize treatment.
Background:
Although respiratory viruses are common triggers of asthma exacerbations, the influence of viral infection characteristics on exacerbation presentation and treatment response in the pediatric emergency department (ED) is unclear.
Objective:
To assess viral infection characteristics of children experiencing ED asthma exacerbations and to test their associations with severity and treatment response.
Methods:
This is a prospective study of children, aged 4 to 18 years, who received standard ED asthma exacerbation treatment with inhaled bronchodilators and systemic corticosteroids. Nasal swabs collected for viral metagenomic analyses determined virus presence, load, and species. Outcomes included exacerbation severity (Pediatric Asthma Severity [PAS] score, clinician impression, and vital signs) and treatment response (discharge home without needing additional asthma therapies).
Results:
Of 107 children, 47% had moderate/severe exacerbations by PAS and 64% demonstrated treatment response. Viral metagenomic analysis on nasal swabs from 73 children detected virus in 86%, with 10 different species identified, primarily rhinovirus A (RV-A), RV-C, and enterovirus D68. Exacerbations involving RV-A were milder (odds ratio [OR] = 0.25; 95% confidence interval [CI] = 0.07-0.83) and tended to be more responsive to treatment than non-RV-A infections, whereas exacerbations involving enterovirus D68 were more severe (OR = 8.3; 95% CI = 1.3-164.7) and had no treatment response association. Viral load was not associated with treatment response but exhibited a strong linear relationship with heart rate (rpartial = 0.48), respiratory rate (rpartial = 0.25), and oxygen saturation (rpartial = -0.25), indicative of severity.
Conclusions:
The majority of ED asthma exacerbations are triggered by respiratory viruses. Viral species are associated with severity and treatment response, suggesting that early pathogen detection could inform ED treatment decisions. Additional studies are needed to identify differences in pathobiology underlying exacerbations triggered by different viral species, and how to effectively treat these heterogeneous exacerbations.
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