Last updated: September 8, 2023

Summarytoggle arrow icon

Bronchiolitis is a lower respiratory tract infection (LRTI) characterized by inflammation of the bronchioles in children < 2 years of age. Respiratory syncytial virus (RSV) is the primary pathogen, although many viruses have been implicated in bronchiolitis. Patients first present with upper respiratory tract infection (URTI) symptoms (e.g., low-grade fever, nasal congestion) followed by a cough, wheezing, and, in severe cases, signs of acute respiratory distress. Bronchiolitis is a clinical diagnosis; diagnostic studies are usually not needed unless the child presents with severe illness that requires an evaluation for associated complications (e.g., superinfection, respiratory acidosis) or if the diagnosis is uncertain. Management consists of supportive treatment (e.g., nasal suction) and close monitoring. Severe illness requires hospitalization for additional management (e.g., IV fluids, respiratory support, nutritional support) and close monitoring of respiratory status. Bronchiolitis prevention includes RSV vaccination of pregnant individuals in the third trimester and routine passive immunization of all infants < 8 months of age with RSV monoclonal antibodies.

Epidemiologytoggle arrow icon

  • Primarily affects children < 2 years of age
  • Peak incidence: 2–6 months of age
  • Common during winter months

Epidemiological data refers to the US, unless otherwise specified.

Etiologytoggle arrow icon

Clinical featurestoggle arrow icon

If significant nasal congestion is present, provide nasal suction and reassess respiratory status to differentiate upper airway involvement (clear breath sounds after nasal suction) from lower airway involvement (abnormal breath sounds after nasal suction). [4]

Symptoms typically peak 3–5 days after onset and then gradually improve over 2–3 weeks. The onset of new symptoms or worsening of existing symptoms (e.g., fever) after 3–5 days should raise concern for complications of bronchiolitis. [1][4]

Diagnosticstoggle arrow icon

General principles [1][6]

Laboratory studies [1][4]

Chest x-ray

Managementtoggle arrow icon

Approach [1][9]

Children with bronchiolitis and oxygen saturation ≥ 90% do not require supplemental oxygen. [1][6]

Avoid bronchodilators, epinephrine, corticosteroids, antibiotics, and chest physiotherapy unless there are comorbidities (e.g., asthma, croup, cystic fibrosis, acute otitis media). [1]

Admission criteria for bronchiolitis [1][9][10]

Inpatient management of bronchiolitis [1][9]

Respiratory support

Hypertonic saline nebulizations may trigger bronchospasm. Discontinue treatment if nebulizations cause severe coughing fits and/or worsen the patient's respiratory status. [12]

Caloric and fluid support

  • Ensure patients receive the recommended daily intake for their age.
  • Encourage normal oral feeds (e.g., with breastmilk, formula, regular diet for age) as tolerated.
  • Consider NG/IV fluids for any of the following: [1]

Respiratory distress increases caloric and fluid requirements but also increases the risk for aspiration during oral feeds. Nutritional and fluid support via a feeding tube (orogastric or nasogastric) and/or intravenously is often necessary. [1]

Other recommendations

Outpatient management of bronchiolitis [1][9]

  • Arrange follow-up within 24 hours. [14]
  • Educate caregivers on:
    • Signs of deterioration and the need to seek immediate medical attention if present [14]
    • How and when to provide nasal suction
    • The expected course of disease
  • Encourage adequate oral caloric and fluid intake.
  • Advise caregivers to avoid exposing the patient to second-hand smoke; offer counseling on smoking cessation for household members.

Advise caregivers to seek immediate medical attention if the child shows signs of deterioration such as dehydration, poor feeding, lethargy or irritation, new fever, and/or signs of respiratory distress. [14]

Differential diagnosestoggle arrow icon

The differential diagnoses listed here are not exhaustive.

Complicationstoggle arrow icon

We list the most important complications. The selection is not exhaustive.

Prognosistoggle arrow icon

  • With timely diagnosis and adequate treatment, the prognosis is good.
  • Bronchiolitis in infancy is associated with an increased risk of developing asthma.

Preventiontoggle arrow icon

General measures [1][2][6]

Administration of respiratory syncytial virus vaccine to pregnant individuals minimizes the risk of bronchiolitis in infants. [15]

RSV prophylaxis [2][16][17]

Indications for RSV prophylaxis and approved agents [2][16][17]
Indications Agent and administration
Routine prophylaxis in 1st RSV season

Indications for additional RSV prophylaxis in 2nd RSV season

Infants < 12 months of age
Children 12–24 months of age

If available, nirsevimab is preferred over palivizumab because it can be administered as a single dose rather than monthly dosing. [16]

Palivizumab and nirsevimab provide RSV (Paramyxovirus) Prophylaxis for Preexisting conditions (e.g., Preterm).

RSV prophylaxis can be administered at the same visit as other age-appropriate vaccines. [16]

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Referencestoggle arrow icon

  1. Brady MT, Byington CL, et al. Updated Guidance for Palivizumab Prophylaxis Among Infants and Young Children at Increased Risk of Hospitalization for Respiratory Syncytial Virus Infection. Pediatrics. 2014; 134 (2): p.e620-e638.doi: 10.1542/peds.2014-1666 . | Open in Read by QxMD
  2. Ralston SL, Lieberthal AS, Meissner HC, et al. Clinical practice guideline: the diagnosis, management, and prevention of bronchiolitis. Pediatrics. 2014; 134 (5): p.e1474-1502.doi: 10.1542/peds.2014-2742 . | Open in Read by QxMD
  3. Smith DK, Seales S, Budzik C. Respiratory Syncytial Virus Bronchiolitis in Children. Am Fam Physician. 2017; 95 (2): p.94-99.
  4. FDA Approves First Vaccine for Pregnant Individuals to Prevent RSV in Infants. . Accessed: August 22, 2023.
  5. ACIP and AAP Recommendations for the Use of the Monoclonal Antibody Nirsevimab for the Prevention of RSV Disease. . Accessed: August 23, 2023.
  6. O’Leary ST, Yonts AB, Gaviria-Agudelo C, Kimberlin DW, Paulsen GC. Summer 2023 ACIP Update: RSV Prevention and Updated Recommendations on Other Vaccines. Pediatrics. 2023.doi: 10.1542/peds.2023-063955 . | Open in Read by QxMD
  7. Fink AK, Graff G, Byington CL, Loeffler DR, Rosenfeld M, Saiman L. Palivizumab and Long-term Outcomes in Cystic Fibrosis. Pediatrics. 2019; 144 (1): p.e20183495.doi: 10.1542/peds.2018-3495 . | Open in Read by QxMD
  8. Florin TA, Plint AC, Zorc JJ. Viral bronchiolitis. Lancet. 2017; 389 (10065): p.211-224.doi: 10.1016/s0140-6736(16)30951-5 . | Open in Read by QxMD
  9. Piedimonte G, Perez MK. Respiratory syncytial virus infection and bronchiolitis. Pediatr Rev. 2014; 35 (12): p.519-530.doi: 10.1542/pir.35-12-519 . | Open in Read by QxMD
  10. Kirolos A, Manti S, Blacow R, et al. A Systematic Review of Clinical Practice Guidelines for the Diagnosis and Management of Bronchiolitis. J Infect Dis. 2020; 222 (Supplement_7): p.S672-S679.doi: 10.1093/infdis/jiz240 . | Open in Read by QxMD
  11. Bedson W, Wilkinson E, Hawcutt D, Mcnamara P. Severity Scores used in the assessment of Bronchiolitis: A systematic review. Paediatric respiratory infection and immun. 2021.doi: 10.1183/13993003.congress-2021.oa2846 . | Open in Read by QxMD
  12. Zhang L, Mendoza-Sassi RA, Wainwright C, Klassen TP. Nebulised hypertonic saline solution for acute bronchiolitis in infants. Cochrane Database Syst Rev. 2017; 2017 (12).doi: 10.1002/14651858.cd006458.pub4 . | Open in Read by QxMD
  13. Siegel JD, Rhinehart E, Jackson M, Chiarello L. 2007 Guideline for Isolation Precautions: Preventing Transmission of Infectious Agents in Health Care Settings. Am J Infect Control. 2007; 35 (10): p.S65-S164.doi: 10.1016/j.ajic.2007.10.007 . | Open in Read by QxMD
  14. Walls R, Hockberger R, Gausche-Hill M. Rosen's Emergency Medicine. Elsevier Health Sciences ; 2018
  15. Farzana R, Hoque M, Kamal MS, Choudhury MMU. Role of Parental Smoking in Severe Bronchiolitis: A Hospital Based Case-Control Study. International Journal of Pediatrics. 2017; 2017: p.1-4.doi: 10.1155/2017/9476367 . | Open in Read by QxMD
  16. Di Cicco M, Kantar A, Masini B, Nuzzi G, Ragazzo V, Peroni D. Structural and functional development in airways throughout childhood: Children are not small adults. Pediatr Pulmonol. 2020; 56 (1): p.240-251.doi: 10.1002/ppul.25169 . | Open in Read by QxMD
  17. Vo AT, Liu DR, Schmidt AR, Festekjian A. Capillary blood gas in infants with bronchiolitis: Can end-tidal capnography replace it?. Am J Emerg Med. 2021; 45: p.144-148.doi: 10.1016/j.ajem.2021.04.056 . | Open in Read by QxMD
  18. McDaniel CE, Ralston S, Lucas B, Schroeder AR. Association of Diagnostic Criteria With Urinary Tract Infection Prevalence in Bronchiolitis. JAMA Pediatr. 2019; 173 (3): p.269.doi: 10.1001/jamapediatrics.2018.5091 . | Open in Read by QxMD

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