Bronchiolitis
=============

* Peter J Gill
* Neil Chanchlani
* Sanjay Mahant

## Bronchiolitis has resurged since COVID-19–related physical distancing measures have been relaxed

Bronchiolitis is a viral lower respiratory tract infection, leading to small airway inflammation and edema, and is usually caused by respiratory syncytial virus.1 Before the COVID-19 pandemic, in Ontario, 2.6/100 children younger than 1 year had a visit to an emergency department for bronchiolitis.2 Incidence decreased during 2020 owing to masking, school closures and physical distancing measures. However, when those were relaxed, many countries experienced off-seasonal resurgence and more presentations of children older than 1 year.3

## Infants typically present with symptoms of viral respiratory infection; neonates may present with apneas or cyanosis only

Most children present with low-grade fever, tachypnea, chest wall retractions and reduced oral intake, with crackles and wheeze bilaterally.1,4 Risk factors for severe bronchiolitis include cardiorespiratory, neuromuscular or immunodeficiency comorbidities; age 3 months or younger; and prematurity.1,4 Bacterial pneumonia should be considered if fever is 39°C or higher or there are unilateral chest signs on auscultation.4

## Investigations are not recommended routinely

Nasopharyngeal swabs do not alter management but may be used to cohort children in hospital.1 Chest radiographs and blood tests are not indicated unless the presentation is severe (i.e., requiring intensive care) or the diagnosis is unclear.1,4 Children should be referred for possible admission if there is moderate increased work in breathing, coughing with sustained vomiting, signs of dehydration, or oxygen saturations less than 90% in room air.1,4

## Treatment remains supportive

Oxygen should be administered to maintain saturations at 90% or higher, including while the patient is asleep. Bronchodilators, inhaled epinephrine, antibiotics, hypertonic saline and corticosteroids are not recommended.1,4 The patient’s nares should be suctioned superficially if excessive secretions impede breathing or feeding.1,4 Compared with intravenous fluids, nasogastric tube hydration avoids cannulation, allows enteral nutrition and reduces irritability due to hunger.5

## Parents should be advised that cough may persist

Although symptoms peak between 3 and 5 days from onset, there is no association between day of illness at admission and hospital length of stay.6 Cough will usually resolve within 2 weeks, but about 10% of children may have persistent cough for 3 weeks or longer.

## Footnotes

*   **Competing interests:** See [www.cmaj.ca/site/misc/cmaj\_staff.xhtml](http://www.cmaj.ca/site/misc/cmaj_staff.xhtml) for Neil Chanchlani. Peter Gill reports receiving grants from the Canadian Institutes of Health Research (CIHR), the PSI Foundation and the Hospital for Sick Children, and fees from the Evidence-Based Medicine Live Steering Committee, and the CIHR Institute of Human Development, Child and Youth Health. Sanjay Mahant reports receiving grants from CIHR and the PSI Foundation (payment to institution). Dr. Mahant also reports receiving personal fees from the *Journal of Hospital Medicine* as an editorial board member.

*   This article has been peer reviewed.

*   **Disclaimer:** Neil Chanchlani is an associate editor for *CMAJ* and was not involved in the editorial decision-making process for this article.

This is an Open Access article distributed in accordance with the terms of the Creative Commons Attribution (CC BY-NC-ND 4.0) licence, which permits use, distribution and reproduction in any medium, provided that the original publication is properly cited, the use is noncommercial (i.e., research or educational use), and no modifications or adaptations are made. See: [https://creativecommons.org/licenses/by-nc-nd/4.0/](https://creativecommons.org/licenses/by-nc-nd/4.0/)

## References

1.  Friedman JN, Rieder MJ, Walton JM; Canadian Paediatric Society, Acute Care Committee DT and HSC Bronchiolitis: recommendations for diagnosis, monitoring and management of children one to 24 months of age. Paediatr Child Health 2014;19:485–98.
    
    [CrossRef](http://www.cmaj.ca/lookup/external-ref?access_num=10.1093/pch/19.9.485&link_type=DOI) 
    
    [PubMed](http://www.cmaj.ca/lookup/external-ref?access_num=25414585&link_type=MED&atom=%2Fcmaj%2F194%2F6%2FE216.atom) 

2.  To T, Terebessy E, Zhu J, et al. Did emergency department visits in infants and young children increase in the last decade? An Ontario, Canada study. Pediatr Emerg Care 2021 Sept. 23 [Epub ahead of print]. doi: 10.1097/PEC.0000000000002535.
    
    [CrossRef](http://www.cmaj.ca/lookup/external-ref?access_num=10.1097/PEC.0000000000002535&link_type=DOI) 

3.  Lavoie PM, Reicherz F, Solimano A, et al. Potential resurgence of respiratory syncytial virus in Canada. CMAJ 2021;193:E1140–1.
    
    [FREE Full Text](http://www.cmaj.ca/lookup/ijlink/YTozOntzOjQ6InBhdGgiO3M6MTQ6Ii9sb29rdXAvaWpsaW5rIjtzOjU6InF1ZXJ5IjthOjQ6e3M6ODoibGlua1R5cGUiO3M6NDoiRlVMTCI7czoxMToiam91cm5hbENvZGUiO3M6NDoiY21haiI7czo1OiJyZXNpZCI7czoxMjoiMTkzLzI5L0UxMTQwIjtzOjQ6ImF0b20iO3M6MjE6Ii9jbWFqLzE5NC82L0UyMTYuYXRvbSI7fXM6ODoiZnJhZ21lbnQiO3M6MDoiIjt9) 

4.  Bronchiolitis in children: diagnosis and management. (NICE Guideline, No. 9.), NICE Guidelines (National Institute for Health and Care Excellence (NICE), London (UK)) updated 2021 Aug. 9.
    
    

5.  Gill PJ, Anwar MR, Kornelsen E, et al. Parenteral versus enteral fluid therapy for children hospitalised with bronchiolitis. Cochrane Database Syst Rev 2021;12(12):CD013552.
    
    

6.  Schroeder AR, Destino LA, Ip W, et al. Day of illness and outcomes in bronchiolitis hospitalizations. Pediatrics 2020 Nov;146:e20201537. doi:10.1542/peds.2020-1537.
    
    [Abstract/FREE Full Text](http://www.cmaj.ca/lookup/ijlink/YTozOntzOjQ6InBhdGgiO3M6MTQ6Ii9sb29rdXAvaWpsaW5rIjtzOjU6InF1ZXJ5IjthOjQ6e3M6ODoibGlua1R5cGUiO3M6NDoiQUJTVCI7czoxMToiam91cm5hbENvZGUiO3M6MTA6InBlZGlhdHJpY3MiO3M6NToicmVzaWQiO3M6MTU6IjE0Ni81L2UyMDIwMTUzNyI7czo0OiJhdG9tIjtzOjIxOiIvY21hai8xOTQvNi9FMjE2LmF0b20iO31zOjg6ImZyYWdtZW50IjtzOjA6IiI7fQ==)