This document provides an overview of bronchiolitis including pathogenesis, microbiology, risk factors, clinical presentation, diagnosis, and treatment recommendations. Bronchiolitis is typically caused by viral infection, most commonly RSV, and causes inflammation in the small airways. Clinical diagnosis is based on symptoms of fever, cough and respiratory distress. Treatment focuses on supportive care like hydration and supplemental oxygen rather than medications like bronchodilators or steroids which studies have shown are not effective. High flow nasal cannula may help reduce respiratory distress. Prevention involves reducing exposure to tobacco smoke which increases risk and severity.

1. BRONCHIOLITIS
MANAGEMENT IN
ED

2. INTRODUCTION
■ Bronchiolitis is broadly defined as a clinical syndrome that occurs in children <2 years
of age and is characterized by upper respiratory symptoms (eg, rhinorrhea) followed
by lower respiratory infection with inflammation, which results in
wheezing and/or crackles (rales). Bronchiolitis typically occurs with primary infection
or reinfection with a viral pathogen
■ PATHOGENESIS: Bronchiolitis occurs when viruses infect the terminal bronchiolar
epithelial cells, causing direct damage and inflammation in the small bronchi and
bronchioles.
■ MICROBIOLOGY: Bronchiolitis typically is caused by a viral infection.Although the
proportion of disease caused by specific viruses varies depending upon the season and
the year, respiratory syncytial virus (RSV) is the most common cause, followed by
rhinovirus. Less common causes include parainfluenza virus, human
metapneumovirus, influenza virus, adenovirus, coronavirus, and human bocavirus

3. ■ RISK FACTORS FOR SEVERE DISEASE — Risk factors for severe or complicated
bronchiolitis include :
– Prematurity (gestational age ≤36 weeks)
– Low birth weight
– Age less than 12 weeks
– Chronic pulmonary disease, particularly bronchopulmonary dysplasia (also known as
chronic lung disease)
– Anatomic defects of the airways
– Hemodynamically significant congenital heart disease
– Immunodeficiency
– Neurologic disease
– Environmental and other risk factors, such as passive smoking, crowded household,
daycare attendance, being born approximately two months before or after the start
of the epidemic, concurrent birth siblings, older siblings, and high altitude (>2500
meters) can also contribute to more severe disease

4. ■ Clinical presentation: Fever (usually ≤38.3ºC [101ºF]), cough, and respiratory distress
(eg, increased respiratory rate, retractions, increased work of breathing, wheezing,
crackles, hypoxia). It often is preceded by a one- to three-day history of upper
respiratory tract symptoms (eg, nasal congestion and/or discharge)
■ Clinical course:Typical illness with bronchiolitis begins with upper respiratory tract
symptoms, followed by lower respiratory tract signs and symptoms on days two to
three, which peak on days three to five and then gradually resolve.
In a systematic review of four studies including 590 children with bronchiolitis, the
mean time to resolution of cough ranged from 8 to 15 days.1
■ Dehydration a major complication: Infants with bronchiolitis may have difficulty
maintaining adequate hydration because of increased fluid needs (related to fever and
tachypnea), decreased oral intake (related to tachypnea and respiratory
distress), and/or vomiting2.They should be monitored for dehydration (eg, increased
heart rate, dry mucosa, sunken fontanelle, decreased urine output

5. HISTORYTAKING
■ Assessment of hydration status (eg, fluid intake, urine output)
■ Symptoms of respiratory distress (tachypnea, nasal flaring, retractions, grunting)
■ Cyanosis
■ Episodes of restlessness or lethargy (may indicate hypoxemia and/or impending
respiratory failure)
■ A history of apnea with or without cyanosis or bradycardia

6. EXAMINATION
■ Respiratory status: Check for tachypnea, intercostal and subcostal retractions, expiratory
wheezing, and cough.
Severely affected patients have increased work of breathing (subcostal, intercostal, and
supraclavicular retractions; nasal flaring; and expiratory grunting).
■ Additional auscultatory findings may include wheezing, prolonged expiratory phase and
coarse or fine crackles (rales).
■ The chest may appear hyperexpanded with increased anteroposterior diameter and may be
hyperresonant to percussion.
■ Hypoxemia (oxygen saturation <95 percent) commonly is detected by pulse oximetry.
■ Other findings may include conjunctivitis, pharyngitis, and acute otitis media
■ Severe signs: cyanosis, poor peripheral perfusion.Wheezing may not be audible if the airways
are profoundly narrowed or when increased work of breathing results in exhaustion

7. DIAGNOSIS
■ Bronchiolitis is diagnosed clinically.
■ When clinicians diagnose bronchiolitis on the basis of history and physical examination,
radiographic or laboratory studies should not be obtained routinely 3
■ Current evidence does not support routine chest radiography in children with bronchiolitis.
Although many infants with bronchiolitis have abnormalities on chest radiography, data
are insufficient to demonstrate that chest radiography correlates well with disease
severity4
■ Initial radiography should be reserved for cases in which respiratory effort is severe enough
to warrant ICU admission or where signs of an airway complication (such as pneumothorax)
are present.
– In 265 study infants, 2 radiographs (0.75%) were read by the reference radiologist as
inconsistent with bronchiolitis (1 cardiomegaly and 1 lobar consolidation; 95% CI, 0-1.8).
Antibiotics were prescribed at disposition for 39 study infants (14.7%), and 31 children
(11.7%) were hospitalized. Intended disposition (ie, discharge versus admission) was the
same pre- and post-radiography in 258 of the 265 cases (97.4%). In contrast, on the basis
of the ED physicians’ radiograph interpretation, 5 times as many children received
antibiotic therapy post-radiography as compared with their intended management plan
pre-radiography (95% CI for the difference)5

8. – In a study6 of 821 patients, 427 chest radiographs were performed, then univariate analysis
was used to identify variables that were significantly related to the realisation of a chest
radiography: age ≤ 3 months (p = 0.03), feeding difficulties (p < 0.001), fever (p < 0.001),
tachypnea (p = 0.002), global score of respiratory distress (p < 0.001), hypoxia (SpO2 <
95%, p < 0.001), crackles (p < 0.001), bronchitis rales (p = 0.04) and toxic appearing (p =
0.04).
Finally, multivariate analysis only identified fever as an independent clinical predictor of
radiographic abnormalities (p = 0.04)
■ Pulse oximetry has been erroneously used in bronchiolitis as a proxy for respiratory
distress. Accuracy of pulse oximetry is poor, especially in the 76% to 90% range.7 Further, it
has been well demonstrated that oxygen saturation has much less impact on respiratory
drive than carbon dioxide concentrations in the blood.8
There is very poor correlation between respiratory distress and oxygen saturations among
infants with lower respiratory tract infections.9 Other than cyanosis, no published clinical
sign, model, or score accurately identifies hypoxemic children

11. TREATMENT
■ Clinicians should not administer albuterol (or salbutamol) to infants and children with
a diagnosis of bronchiolitis (Evidence Quality: B; Recommendation Strength: Strong
Recommendation)3
■ Most randomized controlled trials have failed to demonstrate a consistent benefit
from α- or β-adrenergic agents. Several meta-analyses and systematic reviews 10-15
have shown that bronchodilators may improve clinical symptom scores, but they do
not affect disease resolution, need for hospitalization, or length of stay (LOS).
■ Clinicians should not administer epinephrine to infants and children with a diagnosis of
bronchiolitis (Evidence Quality: B; Recommendation Strength: Strong
Recommendation)3
■ Nebulized hypertonic saline should not be administered to infants with a diagnosis of
bronchiolitis in the emergency department (Evidence Quality: B; Recommendation
Strength: Moderate Recommendation).3

12. ■ Clinicians should not administer systemic corticosteroids to infants with a diagnosis of
bronchiolitis in any setting (Evidence Quality:A; Recommendation Strength: Strong
Recommendation).3
■ Clinicians may choose not to administer supplemental oxygen if the oxyhemoglobin
saturation exceeds 90% in infants and children with a diagnosis of bronchiolitis
(Evidence Quality: D; Recommendation Strength:Weak Recommendation [based on
low-level evidence and reasoning from first principles])3
■ Clinicians should not administer systemic corticosteroids to infants with a diagnosis of
bronchiolitis in any setting (Evidence Quality:A; Recommendation Strength: Strong
Recommendation).3
■ Use of humidified, heated, high-flow nasal cannula to deliver air-oxygen mixtures
provides assistance to infants with bronchiolitis through multiple proposed
mechanisms.16 There is evidence that high-flow nasal cannula improves physiologic
measures of respiratory effort and can generate continuous positive airway pressure in
bronchiolitis.17-20
Clinical evidence suggests it reduces work of breathing21,22 and may decrease need for
shown by the retrospective study from Australia,23 which showed a decline in
intubation rate in the subgroup of infants with bronchiolitis from 37% to 7% after the
introduction of high-flow nasal cannula

13. ■ Clinicians should not use chest physiotherapy for infants and children with a diagnosis
of bronchiolitis (Evidence Quality: B; Recommendation Strength: Moderate
Recommendation).3
■ Clinicians should not administer antibacterial medications to infants and children with
a diagnosis of bronchiolitis unless there is a concomitant bacterial infection, or a
strong suspicion of one. (Evidence Quality: B; Recommendation Strength: Strong
Recommendation).3
– Studies have shown that febrile infants without an identifiable source of fever have
a risk of bacteremia that may be as high as 7%. However, a child with a distinct viral
syndrome, such as bronchiolitis, has a lower risk (much less than 1%) of bacterial
infection of the cerebrospinal fluid or blood.24
– In a recent large retrospective multicenter study, Christakis et al found that the use
of chest radiographs in bronchiolitis is an independent predictor of antibiotic use5
■ Clinicians should administer nasogastric or intravenous fluids for infants with a
diagnosis of bronchiolitis who cannot maintain hydration orally (Evidence Quality: X;
Recommendation Strength: Strong Recommendation)3

14. PREVENTION
■ Clinicians should inquire about the exposure of the infant or child to tobacco smoke
when assessing infants and children for bronchiolitis (Evidence Quality: C;
Recommendation Strength: Moderate Recommendation).3
■ This is because tobacco smoke exposure has shown to increase the risk and severity of
bronchiolitis, as shown by a recent systematic review, Jones et al25 found a pooled
odds ratio of 2.51 (95% CI 1.96 to 3.21) for tobacco smoke exposure and bronchiolitis
hospitalization among the 7 studies specific to the condition

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