Episode 33 – Acute Bronchiolitis: Assessment and Management in the Emergency Department (Pharmacology CME)
Differentiating bronchiolitis from asthma and reactive airway disease in young children can be challenging, and a rapidly changing clinical presentation can confound accurate assessment of the severity of the illness. This episode reviews risk factors for apnea and severe bronchiolitis; discusses treatments/therapies and provides evidence-based recommendations for the management of pediatric patients with bronchiolitis.
- Bronchiolar narrowing and obstruction is caused by:
- Increased mucus secretion
- Cell death and sloughing
- Peri-bronchiolar lymphocytic infiltrate
- Submucosal edema
- Smooth muscle constriction seems to have a limited role, perhaps explaining the lack of response to bronchodilators.
- Median duration of illness is 12 days in children <24 months
- 18% still ill at 3 weeks.2
- 9% still ill at 4 weeks.2
- RSV accounts for 50-80% of cases, but rare in children >2 yo.3
- Late fall epidemic peaking Nov-March, in the US.4
- Human Metapneumovirus (HMPV) accounts for 3-19% 5,6
- Similar seasonal variation to RSV.
- Parainfluenza, influenza, adenoviruses, coronaviruses, rhinoviruses, and enteroviruses are other causes.4-6
- Rhinoviruses have been shown to play a larger role in Asthma.7
- The American Academy of Pediatrics defines it as any of the following in infants: 1
- Use of accessory muscles
- Nasal flaring
- Emergent Causes
- Infection: pneumonia, chlamydia, pertussis
- Foreign body: aspirated or esophageal
- Cardiac anomaly: congestive heart failure, vascular ring
- Allergic reaction
- Bronchopulmonary dysplasia exacerbation
- Non-acute Causes
- Congenital anomaly: tracheoesophageal fistula, bronchogenic cyst, laryngotracheomalacia
- Gastroesophageal reflux disease
- Mediastinal mass
- Cystic fibrosis
- Clinical Pearls
- Vomiting, wheezing, and coughing associated with feeding; consider GERD.
- Wheezing associated with position changes; consider tracheomalacia or great vessel anomalies.
- Wheezing exacerbated by flexion of neck and relieved by neck hyperextension; consider vascular ring.
- Multiple respiratory tract infections and failure to thrive; consider cystic fibrosis or immunodeficiency.
- Wheezing with heart murmur, cardiomegaly, cyanosis, exertion or sweating with feeding; consider cardiac disease.
- Sudden onset of wheezing and choking; consider foreign body.
Risk Factors for Severe Bronchiolitis
- Age < 6-12 weeks11-13
- Prematurity < 35-37 weeks’ gestation11-13
- Underlying respiratory illness such as bronchopulmonary dysplasia1
- Significant congenital heart disease; immune deficiency including HIV, organ or bone marrow transplants, or congenital immune deficiencies14,15
- Altered mental status (impending respiratory failure)
- Dehydration due to inability to tolerate oral fluids
- Ill appearance12
- Oxygen saturation level ≤ 90%1
- Respiratory rate: > 70 breaths/min or higher than normal rate for patient age1,12
- Increased work of breathing: moderate to severe retractions and/or accessory muscle use1
- Nasal flaring
Risk Factors for Apnea
- Full-term birth and < 1 month of age16,17
- Preterm birth (< 37 weeks’ gestation) and age < 2 months post birth11-13,17
- History of apnea of prematurity
- Emergency department presentation with apnea17
- Apnea witnessed by a caregiver17
- Radiographs increase the likely hood of a physician giving antibiotics, even if the X-ray is negative.18-20
- Routine radiography is discouraged, but may be helpful when severe disease requires further evaluation or exclusion of foreign body.
- Viral testing is not necessary for the diagnosis but may help when searching for the cause of fever in young infants.
- 2016 ACEP fever guidelines note that positive viral testing can impact further workup of fever for a serious bacterial infection (SBI).21
- In infants <28 days, serious bacterial infection is high, even in patients with bronchiolitis: 10% (RSV+) and 14% (RSV -)22. Standard fever evaluation is recommended.
- In the 28-60 day old group, SBI rates were 5.5% (RSV+) and 11.7% (RSV-). All were UTIs.22 Urinalysis is recommended.
Emergency Department Treatment
- Keep O2 saturation >90%
- Clinicians may choose not to use continuous pulse oximetry (weak recommendation due to low-level evidence and reasoning)1
- IV or NG administration of fluids to combat dehydration, until respiratory distress and tachypnea resolve.
- Routine use of “deep” suctioning may not be beneficial and may be harmful.1
- Nasal suction should be used to help infants with respiratory distress, poor feeding or sleeping.
- Generally nor recommended for routine use.
- May trial in infants with:
- Severe bronchiolitis (these were excluded in the studies).
- History of prior wheezing.
- Family history of atopy/asthma in an older infant.
- Anticholinergic Agents (ipratropium bromide)
- No evidence for improvement in bronchiolitis.31-34
- AAP1, Cochrane Review27, and PECARN28 study all recommend against, finding no evidence for improvement.
- One small study (70 patients) found a benefit utilising 1 mg/kg oral dexamethasone followed by 0.6 mg/kg daily for 5 days. However, the study limited by size and increased prevalence of family history of atopy.
- Recommendations remain against use in first time wheezers with bronchiolitis.
- Racemic Epinephrine
- Not recommended1. Further study needed.
- Racemic Epinephrine + Oral Dexamethasone
- Pediatric Emergency Research Canada trial at 8 Canadian pediatric EDs involving 800 infants aged 6 weeks to 12 months with bronchiolitis found that the epinephrine-dexamethasone group had a lower admission rate over 7 days than the placebo group (17.1% vs 26.4%). This was not statistically significant. Further study needed. 30
- Hypertonic Saline
- AAP guidelines do not recommend use in the ED but note clinicians may utilize it in the inpatient setting. 1
- Cochrane reviews in 2013 and 2017 found some inpatient benefit, but a conflicting publication found it may worsen cough.35-37
- High Flow Nasal Cannula (HFNC)
- Several small pediatric ICU studies show a benefit in severe cases. No large ED randomized trials exist, to date.
- Study protocols included weight based or age based flow rates.
- Nasal CPAP
- Shows benefit in pediatric ICU settings. Evidence vs HFNC is limited.
- Consider admission if any of the following are present:
- Risk for apnea
- Risk for severe bronchiolitis
- Respiratory distress, particularly if it interferes with feeding
- Hypoxia (oxygen saturation ≤ 90%)
- Decreased feeding and/or dehydration
- An unreliable caregiver (ie, unable to ensure patient care and appropriate 24-hour follow-up)
- All patients with severe bronchiolitis should be admitted.
Last Updated on January 25, 2023