Bronchiolitis

Introduction

• Viral LRTI, generally in infants <12mo (can occur up to 24 months)
  • Seasonal. RSV most common cause. Parainfluenza/adenovirus/rhinovirus/influenza)
• Clinical diagnosis
• No Ix necessary routinely
• Supportive management
• Mortality <1%
• No medication is required routinely
• Peak severity at day 2-3 with resolution over 7-10 days
• Cough may persist for weeks

Pathophysiology

• RSV direct invasion of epithelial cells with inflammatory response
• Lymphocyte infiltration, oedema and smooth muscle spasm (possibly)
  • Main driver is luminal narrowing and debris from infiltration (hence minimal/no benefit of beta-2 agonists)
• Incidence of secondary or concomitant bacterial infection is low
• Can get hyperinflation due to mucous plugging and work of breathing
• Auscultation reveals symmetrical wheeze +- inspiratory crepitations

Assessment

• Usually acute URTI with subsequent respiratory distress, fever and one or more of:
  • Cough
  • Tachypnoea
  • Retractions
  • Widespread crackles/wheeze
  • Apnoea (may be only symptom in neonate)

Risk factors

• Chronological age at presentation <10 weeks
• Chronic lung disease
• Congenital cardiac disease
• Chronic neurological/neuromuscular disease
• Indigenous ethnicity
• Immunodeficiency
• CONSIDER ADMISSION EVEN IF EARLY PRESENTATION WITH MINIMAL Sx

Differential Diagnosis

• Cardiac failure – usually less acute feeding difficulties, poor weight gain, murmur
• Asthma/reactive airways disease
• Pneumonia
• Neonatal sepsis
• Happy wheezer

Assessment

Management

• CXR – Not routine. Often leads to inappropriate Ab use due to atelectasis
• Blood tests – No role in management
• Virological testing – No role in management of individuals

Mild

• Suitable for discharge if no risk factors
• Need minimum of 2 recorded full obs prior to d/c
• Small frequent feeds
• GP Review if early in illness or deterioration
• Parent information sheet

Moderate

• Likely admission or discharge after SSU
• Q1-2h obs (not continuous)
• Once improving and no O2 requirement for 2 hours, discontinue sats monitoring
• NG hydration if <50% of normal fluid intake over 12 hours (2/3 maintenance)
• Target SpO2 >90%. If persistently <90% institute O2 therapy
• Low flow nasal prongs then HF if these fail
• Decision to admit based on risk factors, O2, fluids, monitoring for apnoeas, social factors, phase of illness and progression

Severe

• Admission +- transfer
• Hourly obs with continuous cardiorespiratory monitoring
• NG feeding if <50% intake over 12 hours (2/3 maintenance) or if HFNP
• SpO2 >90%
• HFNC or CPAP
• Consider ICU if: No improvement, persistent desats, significant apnoeas and/or risk factors

Hiflow evidence and rates

• 2L/kg/min up to 10kg then 0.5L/kg above this
• Study of 1472 infants <12 months showed reduced escalation of therapy (12 vs. 23%) with no difference in hospital stay, duration of O2 therapy and rate of adverse events
• Reduced rates of intubation in an ICU-based study compared to historical controls

CXR findings (if performed for severe/unclear)

• Peribronchial cuffing, bilateral hyperinflation, patchy atelectasis
• If high fever, consider pneumonia and CXR
  • High fever suggests more severe clinical course (El-Rhadi et al. 1999)
  • More likely to have CXR changes but unclear if this is atelectasis vs. bacterial infection

Do not use

• Corticosteroids – No benefit
• Adrenaline – No benefit
• Nebulised hypertonic saline
  • Heterogenous systematic reviews and often administered with bronchodilators without benefit
• Antibiotics
• Antivirals
• Nasal suction – Can consider at time of feeding but not routinely used
• Chest physiotherapy

Salbutamol cochrane review

• No evidence of benefit even in those with strong FHx of atopy
• No improvement in oxygenation
• Small difference in clinical score after doses but unclear how clinically relevant this is
• No reduction in hospitalisation
• No difference in duration of hospitalisation
• No difference in time to resolution
• No difference between outpatients and inpatients
• Relative lack of maturity of beta-2 receptors in smooth muscle limits effectiveness in infants

Systemic glucocorticoids

• Meta-analysis in 2013 showed no difference in admission rate, length of stay, clinical score or readmission rate
• Even in children with subsequent admissions for asthma, initial use of corticosteroids showed no benefit

Discharge criteria

• RR <60 if <6mo; <55 if 6-11 mo and <45 if >12mo
• Stable on room air for at least 4 hours with SpO2 >90%
• Adequate oral intake (at least 50%)
• Social situation
• Caretakers confident
• Education

Last Updated on November 9, 2021 by Andrew Crofton