Respiratory viruses affect asthma attack severity and response to treatment
Published online October 3, 2024
Asthma attacks are a leading cause of emergency department (ED) visits and hospitalizations in children. When children present to the ED for an asthma attack, they are treated with inhaled medications to relax lung muscles and open airways, as well as oral steroids to reduce lung inflammation. However, not all children respond well to these treatments – up to 40% do not experience improvement in their breathing and need additional treatments or hospitalization. The underlying causes of these differences in treatment responses are unclear but may be influenced by the presence and type of pathogen triggering the asthma attack. Previous studies have shown that about 60% of asthma attacks in the ED are linked to infection with a respiratory virus. However, these studies only tested for a limited number of viruses, leaving unclear the true prevalence of viral infections in ED treated asthma attacks, as well as whether infection with particular types of viruses influences response to treatments.
In a recent issue of The Journal of Allergy and Clinical Immunology: In Practice, Navanandan et al. present findings from a study of 107 children, aged 4 to 18 years, presenting to the ED for an asthma attack and who received treatment with inhaled bronchodilators and oral or intravenous steroids. They applied an RNA-sequencing metagenomic pipeline to nasal swabs collected from 73 of the children to determine the presence, type, and level of viruses in the samples. The study measured the association between these viral characteristics and two main outcomes: the severity of the asthma attack and treatment response defined as being discharged home without needing additional asthma treatments.
Using a comprehensive, shotgun sequencing approach, Navanandan et al. show that almost all (86%) asthma attacks in the ED are associated with a respiratory virus. They identified ten different types of viruses, with the most common being rhinovirus A, rhinovirus C, and enterovirus D68. Asthma attacks involving rhinovirus A had more favorable outcomes in that they were milder and responded better to treatment, while those involving enterovirus D68 were more severe and tended to be less responsive to treatment. The study also found that viral load (the amount of virus) was linked to vital signs: higher viral loads were associated with increased heart rate and respiratory rate and lower oxygen saturation levels. These findings suggest that identifying the specific type of virus could help ED providers tailor treatment more effectively during asthma attacks to improve outcomes. Future studies are needed to understand patient responses to different types of viruses and how this information can be used to improve treatment and outcomes for children with severe asthma attacks.
The Journal of Allergy and Clinical Immunology: In Practice is an official journal of the AAAAI, focusing on practical information for the practicing clinician.
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