Bronchiolitis (peds)

(Redirected from Respiratory syncytial virus)


Lobes of the lung with related anatomy.
A - Alveoli AS - Septum alveolare BR - Bronchus respiratorius BT - Bronchus terminalis D - Mucous gland DA - Ductus alveolaris M - Musculus N - Nervus PA - Branch of Arteria pulm. PV - Branch of Vena pulm.
  • Most common reason for infant hospitalizations in the US[1]
  • Respiratory syncytial virus (RSV) causes ~70% of cases of bronchiolitis[2]
  • <2yr old (peak 2-6mo age)
  • Preemies, neonates, congenital heart disease are at risk for serious disease
  • Peaks in winter (November to March)
  • Duration = 7-14d (worst during days 3-5)
  • Inflammation, edema, mucus production, and epithelial necrosis of bronchioles lead to lower airway obstruction
    • Hypoxemia due to V/Q mismatch of poorly ventilated alveolar units

Clinical Features

  • Symptoms
  • Signs
    • Tachypnea, cyanosis, wheezing, respiratory distress (retractions, nasal flaring)
    • Fever is usually low-grade or absent
      • If high-grade fever consider otitis media, UTI, or other bacterial infections
  • Assess for dehydration (tachypnea may interfere with feeding)
    • Sunken fontanelle, decreased PO intake, decreased wet diapers, and lethargy

Differential Diagnosis

Pediatric Shortness of Breath



Other diseases with abnormal respiration


CXR of a child with RSV showing the typical bilateral perihilar fullness.
  • Bronchiolitis is a clinical diagnosis
  • Consider rapid RSV testing
    • However, RSV is NOT linked to apnea or acute severity (compared to other causes of bronchiolitis)[3][4]
    • You should NOT use RSV status to drive admission decisions and admission locations (eg, ward, step-down unit, ICU)[5][6]
  • Consider CBC and CRP to assess the risk of superimposed bacterial infection
  • CXR
    • Not routinely necessary : May lead to unnecessary use of antibiotics (atelectasis from airway plugging mimics infiltrate)
    • Consider if patient is critically ill or diagnosis unclear

Concurrent infection risk

Infants <60 days with RSV bronchiolitis and fever

  • Low risk of bacteremia and meningitis in RSV+, still appreciable UTI risk
  • Recommended to still obtain UA in cases of bronchiolitis w/ fever. BCx and CSF not necessary if >28 days old


  • Note that supportive care remains the mainstay of therapy
  • Hydration for all infants

Oxygen/High Flow

It is reasonable to not perform continuous oximetry on infants and children with bronchiolitis[7]

  • O2 (maintain SaO2 >90%)
    • Oxygen saturation alone should not dictate admission (for patients with O2 sat of 88% or above)[8]
  • High flow nasal cannula
    • Multicenter randomized trial showed infants with bronchiolitis and hypoxemia required less escalation of therapy than standard oxygen [9]
    • Primary benefits is from the high flow rate; optimize the flow upon initiation.
    • Initial Settings
      • Temperature: 37C (usually)
      • Initial flow rate: Based on age/weight. Can be started at 1-2 L/kg per min.
      • Oxygen (FiO2): 21% to 100%, based on patient’s prior oxygenation; goal of 94% to 99%.
  • Nasal CPAP or intubation may be necessary for evolving respiratory failure


There is insufficient data to make an evidence-based recommendation about suctioning.

  • Nasopharyngeal suctioning may temporarily relieve symptoms due to decrease in total airway resistance
  • The use of routine “deep” suctioning may lead to increased length of stay based on one small study [7]

Nebulized Hypertonic Saline (3%)

AAP recommends as a possible intervention, but 2014 SABRE trial found no change in discharge or adverse events with nebulised HS.[10]

  • No decrease in hospital admission in 2017 multi-center, RCT for moderate-severe bronchiolitis, with mild adverse events such as worsening of cough were significantly higher in the HS group[11]
  • Only consider administering to infants who require hospitalization[7] (Class B))
    • Suction nares / nasal saline drops

Not Indicated

Randomized controlled trials of bronchodilator or corticosteroid therapy have shown mixed results. Bronchodilators could aggravate the symptoms.[12][13][14]

  • Albuterol/bronchodilator (Class B)[7]
    • May trial if strong family hx of asthma/atopy in older infants, as this may present a greater reactive airway component
  • Racemic Epinephrine (Class B)[7]
  • Steroids[7][15]
    • Consider dexamethasone 0.6-1mg/kg PO or IM x1 in severe cases
    • Note that AAP recommends against systemic steroids in any settings[16]
  • Antibiotics
    • Only indicated if there is strong suspicion of, or proven bacterial infection


Consider Admission

  • Age <3 months
  • Preterm (<34wks)
  • Underlying heart/lung disease
  • Initial SaO2 <88% [8]
    • Sa02 alone should not alone be used as a factor for admission
  • Unable to tolerate PO
  • Tachypnea with accessory muscle use
  • Caregiver unreliable or otherwise unstable home situation

See Also

External Links


  1. Suh M, Movva N, Jiang X, Bylsma LC, Reichert H, Fryzek JP, Nelson CB. Respiratory Syncytial Virus Is the Leading Cause of United States Infant Hospitalizations, 2009-2019: A Study of the National (Nationwide) Inpatient Sample. J Infect Dis. 2022 Aug 15;226(Suppl 2):S154-S163. doi: 10.1093/infdis/jiac120. PMID: 35968878; PMCID: PMC9377046.
  2. Papadopoulos NG; Moustaki M; Tsolia M; Bossios A; Astra E; Prezerakou A (2002). Am J Respir Crit Care Med.
  3. Well-appearing Young Infants with RSV Infection: Guidance Related To Criteria for Admission. Harbor-UCLA Pediatric Infectious Diseases, October 2017
  4. Schroeder AR, et al. Pediatrics 2013;132:e1194-201
  5. Well-appearing Young Infants with RSV Infection: Guidance Related To Criteria for Admission. Harbor-UCLA Pediatric Infectious Diseases, October 2017
  6. Schroeder AR, et al. Pediatrics 2013;132:e1194-201
  7. 7.0 7.1 7.2 7.3 7.4 7.5 Ralston S. et al. Clinical Practice Guideline: The Diagnosis, Management, and Prevention of Bronchiolitis. Pediatrics 134(5) Nov. 2014. 1474 -e150 doi: 10.1542/peds.2014-2742 PDF
  8. 8.0 8.1 Schuh S. et al. Effect of oximetry on hospitalization in bronchiolitis: a randomized clinical trial. JAMA. 2014 Aug 20;312(7):712-8. doi: 10.1001/jama.2014.8637
  9. Franklin, D., Babl, F. E., Schlapbach, L. J., Oakley, E., Craig, S., Neutze, J., … Schibler, A. (2018). A Randomized Trial of High-Flow Oxygen Therapy in Infants with Bronchiolitis. The New England Journal of Medicine, 378(12), 1121–1131.
  10. Everard ML, Hind D, Ugonna K, et al. SABRE: a multicentre randomised control trial of nebulised hypertonic saline in infants hospitalised with acute bronchiolitis. Thorax. 2014;69(12):1105–1112. doi:10.1136/thoraxjnl-2014-205953.
  11. Angoulvant F et al. Effect of Nebulized Hypertonic Saline Treatment in Emergency Departments on the Hospitalization Rate for Acute BronchiolitisA Randomized Clinical Trial. June 5, 2017. JAMA Pediatr. Published online June 5, 2017. doi:10.1001/jamapediatrics.2017.1333.
  12. Bjornson CL. et al. A randomized trial of a single dose of oral dexamethasone for mild croup. NEJM. 2004;351:1306-1313.
  13. Geelhoed GC. et al. Efficacy of a small single dose of oral dexamethasone for outpatient croup: a double blind placebo controlled clinical trial. BMJ. 1996;313:140-142
  14. Ralston S. et al. Randomized, placebo-controlled trial of albuterol and epinephrine at equipotent beta-2 agonist doses in acute bronchiolitis. Pediatr Pulmonol. 2005;40:292-299
  15. Corneli HM, Zorc JJ, Mahajan P, et al; Bronchiolitis Study Group of the Pediatric Emergency Care Applied Research Net- work (PECARN). A multicenter, random- ized, controlled trial of dexamethasone for bronchiolitis [published correction appears in N Engl J Med 2008;359(18): 1972]. N Engl J Med. 2007;357(4):331–339
  16. Clinical Practice Guideline: The Diagnosis, Management, and Prevention of Bronchiolitis. Pediatrics November 2014; 134 (5): e1474–e1502. 10.1542/peds.2014-2742