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Respiratory syncytial virus infection
Background
Overview
Definition
Bronchiolitis is an inflammatory condition primarily affecting the small airways or bronchioles, often characterized by acute viral infection in infants and young children.
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Pathophysiology
The pathophysiology of bronchiolitis involves the infection of the epithelial cells lining the small airways, predominantly by the RSV. This infection leads to cell damage, increased mucus production, and inflammation, resulting in airway obstruction.
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Epidemiology
It is estimated that 33 million cases of RSV-associated acute lower respiratory infections occurred globally in children < 5 years old in 2019.
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Risk factors
Risk factors for bronchiolitis include age (< 2 years), pre-existing respiratory conditions (asthma, allergic bronchopulmonary aspergillosis, hypersensitivity pneumonitis), infections, exposure to environmental factors (such as cigarette smoke, toxic fumes, and gases), diffuse chronic aspiration, and certain drugs (antimicrobials, anticancer agents, anticonvulsants, cardiovascular agents).
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Disease course
Clinically, bronchiolitis typically begins as an upper respiratory tract infection, progressing to lower respiratory symptoms such as cough, wheezing, and respiratory distress.
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Prognosis and risk of recurrence
The prognosis of bronchiolitis is generally good, with most cases being self-limiting and resolving without complications.
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Guidelines
Key sources
The following summarized guidelines for the evaluation and management of respiratory syncytial virus infection are prepared by our editorial team based on guidelines from the Center for Disease Control (CDC 2024,2023), the American Academy of Family Physicians (AAFP 2023), the American College of Obstetricians and Gynecologists (ACOG 2023), the French Group for Pediatric Intensive Care and Emergencies (GFRUP 2023), the ...
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Screening and diagnosis
Classification and risk stratification
Risk assessment: as per PREDICT 2019 guidelines, regard the following as risk factors for more serious illness:
gestational age < 37 weeks
chronological age at presentation < 10 weeks
indigenous ethnicity
breastfeeding for < 2 months
exposure to cigarette smoke
failure to thrive
chronic pulmonary, heart, or neurological disease.
B
Diagnostic investigations
Clinical assessment: as per GFRUP 2023 guidelines, consider using clinical scores (such as the modified Wood's Clinical Asthma Score, the Wang score, and the Critical Bronchiolitis Score) for the initial assessment and follow-up.
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Modified Wood's Clinical Asthma Score (mWCAS)
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When to use
Peripheral oxygen saturation
≥ 95%, on room air
90-94%, on room air
≥ 90%, with a fraction of inspired oxygen > 0.21
< 90%, with a fraction of inspired oxygen > 0.21
Inspiratory breath sounds
Normal
Mild
Moderate
Decreased/absent
Expiratory wheezing
None
Mild
Moderate
Marked
Use of accessory muscles
None
Mild
Moderate
Maximal
Cerebral function
Normal
Agitated when disturbed
Depressed/agitated
Markedly depressed/coma
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CXR
CXR (SHP)
Chest ultrasound
Laboratory tests
Respiratory support
Oxygen monitoring: as per GFRUP 2023 guidelines, consider monitoring the trend of respiratory parameters and/or clinical scores to assess disease evolution. Avoid obtaining systematic monitoring of pCO2 (and tcpCO2).
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Oxygen monitoring (SHP)
Supplemental oxygen
Noninvasive ventilation
Invasive ventilation
Medical management
Setting of care, hospital admission: as per CPS 2021 guidelines, decide on hospital admission based on clinical judgment, factoring in the risk for progression to severe disease, respiratory status, ability to maintain adequate hydration and the family's ability to cope at home.
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Setting of care (pediatric ICU admission)
Supportive care
Nebulized hypertonic saline
Nebulized epinephrine
Bronchodilators
Bronchodilators (SHP)
Corticosteroids
Corticosteroids (SHP)
Antibiotics
Therapies with no evidence for benefit
Nonpharmacologic interventions
Chest physiotherapy: as per AAFP 2023 guidelines, do not offer chest physiotherapy for the treatment of RSV bronchiolitis.
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Nasal suctioning
Patient education
General counseling: as per AAP 2014 guidelines, ask about the exposure of the infant or child to tobacco smoke when assessing infants and children for bronchiolitis.
B
counsel caregivers about exposing the infant or child to environmental tobacco smoke and smoking cessation when assessing infants and children for bronchiolitis. B
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Preventative measures
Adult immunization: as per CDC 2024 guidelines, offer a single dose of an approved RSV vaccine in all adults aged ≥ 75 years and in adults aged 60-74 years at increased risk for severe RSV disease, such as with certain chronic medical conditions, with moderate or severe immunocompromise, and persons living in nursing homes.
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Maternal immunization
Nirsevimab prophylaxis
Palivizumab prophylaxis (general principles)
Palivizumab prophylaxis (prematurity)
Palivizumab prophylaxis (multiple birth)
Palivizumab prophylaxis (congenital heart disease)
Palivizumab prophylaxis (immunodeficiency)
Palivizumab prophylaxis (cystic fibrosis)
Palivizumab prophylaxis (Down syndrome)
Palivizumab prophylaxis (other comorbidities)
Palivizumab prophylaxis (prevention of wheezing or asthma)
Palivizumab prophylaxis (prevention of healthcare-associated RSV infection)
Palivizumab prophylaxis (remote communities)
Palivizumab prophylaxis (regimens)
Hand hygiene
Follow-up and surveillance
Discharge from hospital
As per PREDICT 2019 guidelines:
Take into account oxygen saturations, adequacy of feeding, age (< 8 weeks), and lack of social support at the time of discharge as a risk for representation.
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Consider discharging infant patients at low risk for severe bronchiolitis, after a period of observation, on home oxygen with a clear return-to-hospital advice.
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Management of chronic cough