Current Management of Acute Bronchiolitis: An Evidence-Based Approach

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The authors review the current American Academy of Pediatric guidelines on diagnosing and managing this most common cause of hospitalization in the first 12 months of life.

Author(s)

John E. Schneider, MD

Joel M. Clingenpeel, MD, MPH, MS.medl

Case

An 8-week-old male infant was brought to the ED by his parents after an episode in which it appeared the baby had stopped breathing. The parents stated that while lying on his mother’s lap at home, the patient stopped breathing for approximately 10 to 15 seconds, during which time his face exhibited a bluish color. They further noted that the patient began breathing again after gentle stimulation and had been acting normally since.

The patient was born at 39 weeks gestation via normal vaginal delivery and without any complications. His parents further stated that prior to the cessation of breathing incident, his symptoms of nasal congestion, decreased energy level, and fast breathing had gradually worsened over the past 2 days. The parents also noted that the infant had not been feeding as well over the past 2 days.

Upon arrival, the patient’s vital signs were: heart rate, 140 beats/minute; respiratory rate (RR), 72 beats/minute; and temperature 101.3°F. Oxygen saturation was 92% on room air. On physical examination, the infant had significant rhinorrhea, moderate intercostal and supraclavicular retractions, ausculatory wheezes, and transmitted upper airway noises throughout.

Overview

Bronchiolitis, a disorder caused by a viral lower respiratory tract infection, is the most common lower respiratory infection in children younger than age 2 years.¹ In 2014, the American Academy of Pediatrics (AAP) characterized bronchiolitis as “rhinitis, cough, tachypnea, wheezing, rales, use of accessory muscles, and/or nasal flaring in children under 24 months of age.”² This condition is the most common cause of hospitalization in the first 12 months of life. It is responsible for over 100,000 admissions annually at an estimated cost to the healthcare system of $1.73 billion.³

Etiology and Pathophysiology

Respiratory syncytial virus (RSV) is the most common cause of bronchiolitis. In the United States, the highest incidence of infection occurs during the months of December through March, with some degree of regional variability.⁴ A number of other viruses that can cause bronchiolitis include human metapneumovirus, parainfluenza virus, and influenza virus.¹ Infection with RSV does not grant permanent immunity, and reinfection is common throughout life.²

Pathophysiologically, bronchiolitis is characterized by an invasion of bronchial epithelial cells that lead to to cell death and sloughing into the bronchial lumen. This, coupled with increased mucous production and submucosal edema, leads to a narrowing of the bronchial lumen and obstruction of airflow.⁵

Clinical Manifestations

Bronchiolitis represents a constellation of signs and symptoms beginning with those of an upper respiratory tract infection, including nasal congestion and rhinorrhea with mild cough. On days 3 to 5, the following symptoms develop: tachypnea, wheezing, rales, and signs of respiratory distress (eg, grunting, nasal flaring, inter-/subcostal retractions). Approximately two-thirds of patients will develop a fever.² Recovery tends to begin around days 5 to 7, with the median duration of illness being 12 days.¹ It should be noted that bronchiolitis represents a highly variable and dynamic disease state. Transient episodes of improvement and worsening are common, emphasizing the importance of serial examinations and assessments. Though rare, progression to respiratory failure and death do occur.²

History and Risk Stratification

The focus of the initial history by the clinician should serve two primary purposes. First, it is important to differentiate infants with probable bronchiolitis from those with other disease states having similar clinical manifestations. One of the most challenging diseases to differentiate from bronchiolitis is that of reactive airway disease (RAD). Eliciting a history of allergic rhinitis, eczema, or a family history of asthma may be helpful in determining the precise etiology of the patient’s symptoms. Although no longer recommended for children with bronchiolitis (as will be later discussed), a trial of a bronchodilation may be beneficial in the setting of familial atopy.

The second—and perhaps most important—aspect of patient history is to determine the presence of risk factors for both apnea and the development of severe bronchiolitis. Regarding the risk factors for apnea, Willwerth et al⁶ developed a set of criteria to identify patients at high risk for apnea in the inpatient setting. Patients were considered high risk if they were born at full term and were younger than 1 month of age; if they were born preterm (<37 weeks gestation) and were younger than 48 weeks postconception; and/or if the infant’s parents or a clinician had already witnessed an episode of apnea during the patient’s illness. In this study, all patients who developed apnea were correctly identified by the risk criteria.⁶ Risk factors for severe bronchiolitis include the following: patient age younger than 12 weeks; patient prematurity younger than 37 weeks gestation; and an underlying hemodynamically significant congenital heart disease, chronic lung disease/bronchopulmonary dysplasia, or an immunocompromised state.¹

Diagnosis

In 2014, the AAP updated its guidelines on the diagnosis, management, and prevention of bronchiolitis. One of the strongest statements in these guidelines emphasize that the diagnosis of bronchiolitis should be based almost exclusively on the history and physical examination.² In children younger than age 2 years, historical features such as a viral prodrome, followed by progressively worsening increased respiratory effort and signs and symptoms of lower respiratory-tract disease (eg, wheezing), should guide clinicians to the diagnosis of bronchiolitis. Although nonspecific, physical examination findings such as rhinorrhea, cough, tachypnea, wheezing, rales, and increased respiratory effort—when coupled with a good history—can be beneficial in the diagnosis of bronchiolitis.

Pulse Oximetry

Pulse oximetry has become a standard part of the clinical assessment of patients with bronchiolitis. This is based on data suggesting that pulse oximetry detects hypoxia in cases where it was not suspected on physical examination alone.⁷ However, the effectiveness of pulse oximetry in predicting clinical outcomes is limited. Pulse oximetry should not be used as a proxy for respiratory distress, as studies have shown poor correlation between respiratory distress and oxygen saturations in infants with lower respiratory tract infection.⁸

Radiographic Evaluation

Regarding the diagnosis of bronchiolitis, the AAP notes, “radiographic and laboratory studies should not be obtained routinely.”² While many children with bronchiolitis may have abnormalities on radiographs, there is insufficient data to suggest that chest radiographs correlate with disease severity. In addition, several studies, including a prospective cohort study by Schuh et al,⁹ have shown that infants with suspected lower respiratory tract infections who undergo radiography are more likely to receive antibiotics without any difference in outcomes.

Laboratory Studies

As stated in the AAP guidelines, routine laboratory testing, particularly virologic studies for RSV, have little role in the diagnosis of bronchiolitis. Since numerous viruses can cause bronchiolitis and have similar clinical presentations, the absence of identification of a particular virologic agent does not exclude the diagnosis of bronchiolitis and is moreover unlikely to alter management.

Although routine laboratory evaluation is not recommended in infants with bronchiolitis, one subgroup in which it may be beneficial is in the assessment of serious bacterial infections (SBIs) in febrile infants with bronchiolitis who are younger than 60 days old. Levine et al¹⁰ conducted a large, multicenter, prospective, cross-sectional study of young, febrile infants to determine the risk of SBI in those with RSV bronchiolitis versus those without RSV bronchiolitis. They found that overall febrile infants younger than age 60 days with RSV bronchiolitis have a lower rate of SBI than those without RSV (7% v 12.5%, respectively).¹⁰ In infants between age 28 and 60 days with RSV bronchiolitis, the origin of all SBIs in the study were urinary tract infections. In patients younger than 28 days of age, the risk of developing an SBI was found to be no different between the RSV-positive and RSV-negative groups.¹⁰

Based on the findings in this study, it is recommended that, at the very least, urinalysis for bacterial infection be performed in all infants with RSV bronchiolitis who are younger than age 60 days. Furthermore, since there was no difference in the rates of SBI in patients younger than age 28 days, infants in this age range should undergo a full septic work-up (blood, urine, and cerebrospinal fluid)—regardless of RSV infection status. For infants between ages 28 and 60 days, there is not enough evidence to recommend for or against further laboratory evaluation other than urinalysis.

Treatment

Nasal Suctioning

Nasal suctioning has become the first-line treatment for infants with bronchiolitis. It is used to clear secretions from the nasal passages to aid in respiration, which is particularly important in younger infants—who are obligate nose breathers. Current recommendations are to perform suctioning with increasing respiratory effort, before feeding and before laying the infant down to sleep.¹

Bronchodilators

In the past, bronchodilators such as the β-agonist albuterol have been used to treat bronchiolitis with the idea that bronchial smooth muscle relaxation would improve clinical symptoms. In its 2006 guidelines, the AAP had recommended a trial of albuterol and continuation only if there was a documented objective response. In the 2014 updated guidelines, however, the AAP no longer recommends the use of albuterol in any capacity.

Although several meta-analyses and systematic reviews have demonstrated that bronchodilators may improve clinical symptoms scores, they did not affect disease resolution, need for hospitalization, or length of hospital stay.² In addition, a recent Cochrane systematic review noted no benefit in the clinical course of infants with bronchiolitis treated with bronchodilators, and cited the potential adverse events (tachycardia and tremors) as outweighing any potential benefit.¹¹ In addition to albuterol, the AAP no longer recommends the use of nebulized epinephrine in the treatment of bronchiolitis.²

Hypertonic Saline

Although hypertonic saline (HTS) has been increasingly studied for the treatment of bronchiolitis, the AAP does not recommend its use in the ED. Despite evidence that HTS may reduce hospital length of stay after 24 hours of use in settings where the typical duration of hospitalization exceeds 3 days, it has not been shown to reduce the rate of hospitalization when used in an emergency setting.²

Corticosteroids

While there is good evidence that corticosteroids are beneficial in treating some respiratory diseases, such as asthma and croup, numerous studies have repeatedly failed to show a benefit in treating bronchiolitis. One of the largest studies, a multicenter, randomized, controlled trial of dexamethasone for bronchiolitis by the Pediatric Emergency Care Applied Research Network, did not show any alteration in admission rates, respiratory status after 4 hours of observation, or length of hospital stay.¹² Accordingly, the AAP strongly recommends against the administration of corticosteroids for bronchiolitis in any setting.²

Oxygen Therapy

Oxygen therapy is often necessary in patients with bronchiolitis who demonstrate hypoxia. The definition of hypoxia in this patient population has remained variable. The AAP has established a threshold of oxyhemoglobin saturation (SpO₂) of less than 90% to define hypoxia and has empowered clinicians to not administer oxygen if the SpO₂ exceeds 90%. Based on the oxyhemoglobin dissociation curve, the authors of the AAP guidelines note that when the SpO₂ is less than 90%, small decreases in the arterial partial pressure of oxygen (PaO₂) result in large decreases in the SpO₂. When SpO₂ is greater than 90%, however, large increases in PaO₂ are associated with only small increased in SpO₂. The AAP guidelines note, “In infants and children with bronchiolitis, no data exist to suggest that such increases [in PaO₂ and SpO₂] result in any clinically significant differences in physiologic function, patient symptoms, or clinical outcomes.”²

A relatively new method of administration of oxygen to infants with bronchiolitis is via a humidified, heated, high-flow nasal cannula (HHHFNC). This therapy has been shown to generate continuous positive airway pressure, which improves respiratory effort, reduces the work of breathing, and may decrease the need for intubation.²

Patient Disposition

One of the most challenging tasks for emergency physicians (EPs) is determining the appropriate disposition of infants with bronchiolitis. The variable presentation and dynamic nature of the disease make this particularly difficult. Patients at high risk for apnea should be admitted to the hospital for observation and further care as needed. Admission also should be strongly considered for those with significantly increased work of breathing and tachypnea that does not improve with suctioning—especially when these interfere with feeding. Infants with poor feeding or evidence of dehydration should be admitted to the hospital for intravenous (IV) fluid hydration or nasogastric feedings. Patients with hypoxia (SpO₂ saturations <90%) should also be admitted for supplemental oxygen therapy. It should be noted, however, the AAP recommends “spot-checks” over continuous pulse oximetry in patients who do not require oxygen therapy.²

Another important factor affecting patient disposition is the ability of the caregiver to provide basic patient care and ensure close outpatient follow-up. Prior to discharge, caregivers should be educated on the highly dynamic nature of bronchiolitis and the signs and symptoms that would require prompt return to the ED—especially if the infant has risk factors for the development of severe disease.

Case Conclusion

Based on the patient’s symptoms, history (most notably, the recent incident of sleep apnea at home), and physical examination, the EP quickly identified this infant was at a high risk for both severe bronchiolitis and apnea and required aggressive management. Nasal suctioning was immediately performed to help clear the patient’s secretions; this, however, only slightly improved his RR and work of breathing. Although the infant’s SpO₂ was greater than 90% on room air, the EP administered oxygen via HHHFNC at 6 L per minute, which produced a significant improvement in both RR and effort.

Given the patient’s age and the presence of a fever, a urinalysis was also obtained, the results of which showed no evidence of infection. Since the patient was only able to bottle-feed for a few minutes at a time, the EP initiated IV fluid hydration and contacted the hospitalist team for inpatient admission.

The infant was gradually weaned from HHHFNC on hospital day 2 but remained with suboptimal oral intake for another 24 hours. By hospital day 4, his work of breathing had improved significantly, and he was feeding well with through the assistance of pre-feeding nasal syringe suctioning. The patient was discharged home in the care of his parents later that same day with only mild tachypnea over baseline. At discharge, the EP emphasized the importance of providing close follow-up with their son’s pediatrician. The infant continued to gradually improve as an outpatient, with resolution of nasal congestion by day 12 of his illness; he returned to his baseline breathing and feeding pattern on day 14.

Dr Schneider is a pediatric emergency medicine fellow, Eastern Virginia Medical School, Children’s Hospital of The King’s Daughters, Norfolk. Dr Clingenpeel is a fellowship director of pediatric emergency medicine, and an associate professor of pediatrics, Eastern Virginia Medical School, Norfolk.

References

Joseph M. Evidence-based assessment and management of acute bronchiolitis in the emergency department. Pediatr Emerg Med Pract. 2011;8(3):1-20.
Ralston SL, Lieberthal AS, Meissner HC, et al; American Academy of Pediatrics. Clinical practice guidelines: the diagnosis, management, and prevention of bronchiolitis [Published correction appears in Pediatrics. 2014;134(5):e1474-e1502]. Pediatrics. 2014;134:5 e1474-e1502.
Hasegawa K, Tsugawa Y, Brown DF, Mansbach JM, Camargo CA Jr. Trends in bronchiolitis hospitalizations in the United States, 2000-20009. Pediatrics. 2013;32(1):28-36.
Centers for Disease Control and Prevention (CDC). Respiratory syncytial virus activity—United States, July 2011-January 2013. MMWR Morb Mortal Wkly Rep. 2013;62(8):141-144.
Harper MB, Fleisher GR. Infectious emergencies. In: Fleisher GR, Ludwig S, eds. Textbook of Pediatric Emergency Medicine. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins;2010:916-917.
Willwerth BM, Harper MB, Greenes DS. Identifying hospitalized infants who have bronchiolitis and are at high risk for apnea. Ann Emerg Med. 2006;48(4):441-447.
Shaw KN, Bell LM, Sherman NH. Outpatient assessment of infants with bronchiolitis. Am J Dis Child. 1991;145(2):151-155.
Wang EE, Milner RA, Navas L, Maj H. Observer agreement for respiratory signs and oximetry in infants hospitalized with lower respiratory infections. Am Rev Respir Dis. 1992;145(1):106-109.
Schuh S, Lalani A, Allen U, et al. Evaluation of the utility of radiography in acute bronchiolitis. J Pediatr. 2007;150(4):429-433.
Levine DA, Platt SL, Dayan PS, et al; Multicenter RSV-SBI Study Group of the Pediatric Emergency Medicine Collaborative Research Committee of the American Academy of Pediatrics. Risk of serious bacterial infection in young febrile infants with respiratory syncytial virus infection. Pediatrics. 2004;113(6):1728-1734.
Gadomski AM, Scribani MB. Bronchodilators for bronchiolitis. Cochrane Database Syst Rev. 2014;(6):CD001266.
Corneli HM, Zorc JJ, Majahan P, et al; Bronchiolitis Study Group of the Pediatric Emergency Care Applied Research Network (PECARN). A multicenter, randomized, controlled trial of dexamethasone for bronchiolitis. N Engl J Med. 2007;357(4):331-339.

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Case Reports

Author(s)

John E. Schneider, MD

Joel M. Clingenpeel, MD, MPH, MS.medl

Author(s)

John E. Schneider, MD

Joel M. Clingenpeel, MD, MPH, MS.medl

Author and Disclosure Information

The authors review the current American Academy of Pediatric guidelines on diagnosing and managing this most common cause of hospitalization in the first 12 months of life.

Case

An 8-week-old male infant was brought to the ED by his parents after an episode in which it appeared the baby had stopped breathing. The parents stated that while lying on his mother’s lap at home, the patient stopped breathing for approximately 10 to 15 seconds, during which time his face exhibited a bluish color. They further noted that the patient began breathing again after gentle stimulation and had been acting normally since.

The patient was born at 39 weeks gestation via normal vaginal delivery and without any complications. His parents further stated that prior to the cessation of breathing incident, his symptoms of nasal congestion, decreased energy level, and fast breathing had gradually worsened over the past 2 days. The parents also noted that the infant had not been feeding as well over the past 2 days.

Upon arrival, the patient’s vital signs were: heart rate, 140 beats/minute; respiratory rate (RR), 72 beats/minute; and temperature 101.3°F. Oxygen saturation was 92% on room air. On physical examination, the infant had significant rhinorrhea, moderate intercostal and supraclavicular retractions, ausculatory wheezes, and transmitted upper airway noises throughout.

Overview

Bronchiolitis, a disorder caused by a viral lower respiratory tract infection, is the most common lower respiratory infection in children younger than age 2 years.¹ In 2014, the American Academy of Pediatrics (AAP) characterized bronchiolitis as “rhinitis, cough, tachypnea, wheezing, rales, use of accessory muscles, and/or nasal flaring in children under 24 months of age.”² This condition is the most common cause of hospitalization in the first 12 months of life. It is responsible for over 100,000 admissions annually at an estimated cost to the healthcare system of $1.73 billion.³

Etiology and Pathophysiology

Respiratory syncytial virus (RSV) is the most common cause of bronchiolitis. In the United States, the highest incidence of infection occurs during the months of December through March, with some degree of regional variability.⁴ A number of other viruses that can cause bronchiolitis include human metapneumovirus, parainfluenza virus, and influenza virus.¹ Infection with RSV does not grant permanent immunity, and reinfection is common throughout life.²

Pathophysiologically, bronchiolitis is characterized by an invasion of bronchial epithelial cells that lead to to cell death and sloughing into the bronchial lumen. This, coupled with increased mucous production and submucosal edema, leads to a narrowing of the bronchial lumen and obstruction of airflow.⁵

Clinical Manifestations

Bronchiolitis represents a constellation of signs and symptoms beginning with those of an upper respiratory tract infection, including nasal congestion and rhinorrhea with mild cough. On days 3 to 5, the following symptoms develop: tachypnea, wheezing, rales, and signs of respiratory distress (eg, grunting, nasal flaring, inter-/subcostal retractions). Approximately two-thirds of patients will develop a fever.² Recovery tends to begin around days 5 to 7, with the median duration of illness being 12 days.¹ It should be noted that bronchiolitis represents a highly variable and dynamic disease state. Transient episodes of improvement and worsening are common, emphasizing the importance of serial examinations and assessments. Though rare, progression to respiratory failure and death do occur.²

History and Risk Stratification

The focus of the initial history by the clinician should serve two primary purposes. First, it is important to differentiate infants with probable bronchiolitis from those with other disease states having similar clinical manifestations. One of the most challenging diseases to differentiate from bronchiolitis is that of reactive airway disease (RAD). Eliciting a history of allergic rhinitis, eczema, or a family history of asthma may be helpful in determining the precise etiology of the patient’s symptoms. Although no longer recommended for children with bronchiolitis (as will be later discussed), a trial of a bronchodilation may be beneficial in the setting of familial atopy.

The second—and perhaps most important—aspect of patient history is to determine the presence of risk factors for both apnea and the development of severe bronchiolitis. Regarding the risk factors for apnea, Willwerth et al⁶ developed a set of criteria to identify patients at high risk for apnea in the inpatient setting. Patients were considered high risk if they were born at full term and were younger than 1 month of age; if they were born preterm (<37 weeks gestation) and were younger than 48 weeks postconception; and/or if the infant’s parents or a clinician had already witnessed an episode of apnea during the patient’s illness. In this study, all patients who developed apnea were correctly identified by the risk criteria.⁶ Risk factors for severe bronchiolitis include the following: patient age younger than 12 weeks; patient prematurity younger than 37 weeks gestation; and an underlying hemodynamically significant congenital heart disease, chronic lung disease/bronchopulmonary dysplasia, or an immunocompromised state.¹

Diagnosis

In 2014, the AAP updated its guidelines on the diagnosis, management, and prevention of bronchiolitis. One of the strongest statements in these guidelines emphasize that the diagnosis of bronchiolitis should be based almost exclusively on the history and physical examination.² In children younger than age 2 years, historical features such as a viral prodrome, followed by progressively worsening increased respiratory effort and signs and symptoms of lower respiratory-tract disease (eg, wheezing), should guide clinicians to the diagnosis of bronchiolitis. Although nonspecific, physical examination findings such as rhinorrhea, cough, tachypnea, wheezing, rales, and increased respiratory effort—when coupled with a good history—can be beneficial in the diagnosis of bronchiolitis.

Pulse Oximetry

Pulse oximetry has become a standard part of the clinical assessment of patients with bronchiolitis. This is based on data suggesting that pulse oximetry detects hypoxia in cases where it was not suspected on physical examination alone.⁷ However, the effectiveness of pulse oximetry in predicting clinical outcomes is limited. Pulse oximetry should not be used as a proxy for respiratory distress, as studies have shown poor correlation between respiratory distress and oxygen saturations in infants with lower respiratory tract infection.⁸

Radiographic Evaluation

Regarding the diagnosis of bronchiolitis, the AAP notes, “radiographic and laboratory studies should not be obtained routinely.”² While many children with bronchiolitis may have abnormalities on radiographs, there is insufficient data to suggest that chest radiographs correlate with disease severity. In addition, several studies, including a prospective cohort study by Schuh et al,⁹ have shown that infants with suspected lower respiratory tract infections who undergo radiography are more likely to receive antibiotics without any difference in outcomes.

Laboratory Studies

As stated in the AAP guidelines, routine laboratory testing, particularly virologic studies for RSV, have little role in the diagnosis of bronchiolitis. Since numerous viruses can cause bronchiolitis and have similar clinical presentations, the absence of identification of a particular virologic agent does not exclude the diagnosis of bronchiolitis and is moreover unlikely to alter management.

Although routine laboratory evaluation is not recommended in infants with bronchiolitis, one subgroup in which it may be beneficial is in the assessment of serious bacterial infections (SBIs) in febrile infants with bronchiolitis who are younger than 60 days old. Levine et al¹⁰ conducted a large, multicenter, prospective, cross-sectional study of young, febrile infants to determine the risk of SBI in those with RSV bronchiolitis versus those without RSV bronchiolitis. They found that overall febrile infants younger than age 60 days with RSV bronchiolitis have a lower rate of SBI than those without RSV (7% v 12.5%, respectively).¹⁰ In infants between age 28 and 60 days with RSV bronchiolitis, the origin of all SBIs in the study were urinary tract infections. In patients younger than 28 days of age, the risk of developing an SBI was found to be no different between the RSV-positive and RSV-negative groups.¹⁰

Based on the findings in this study, it is recommended that, at the very least, urinalysis for bacterial infection be performed in all infants with RSV bronchiolitis who are younger than age 60 days. Furthermore, since there was no difference in the rates of SBI in patients younger than age 28 days, infants in this age range should undergo a full septic work-up (blood, urine, and cerebrospinal fluid)—regardless of RSV infection status. For infants between ages 28 and 60 days, there is not enough evidence to recommend for or against further laboratory evaluation other than urinalysis.

Treatment

Nasal Suctioning

Nasal suctioning has become the first-line treatment for infants with bronchiolitis. It is used to clear secretions from the nasal passages to aid in respiration, which is particularly important in younger infants—who are obligate nose breathers. Current recommendations are to perform suctioning with increasing respiratory effort, before feeding and before laying the infant down to sleep.¹

Bronchodilators

In the past, bronchodilators such as the β-agonist albuterol have been used to treat bronchiolitis with the idea that bronchial smooth muscle relaxation would improve clinical symptoms. In its 2006 guidelines, the AAP had recommended a trial of albuterol and continuation only if there was a documented objective response. In the 2014 updated guidelines, however, the AAP no longer recommends the use of albuterol in any capacity.

Although several meta-analyses and systematic reviews have demonstrated that bronchodilators may improve clinical symptoms scores, they did not affect disease resolution, need for hospitalization, or length of hospital stay.² In addition, a recent Cochrane systematic review noted no benefit in the clinical course of infants with bronchiolitis treated with bronchodilators, and cited the potential adverse events (tachycardia and tremors) as outweighing any potential benefit.¹¹ In addition to albuterol, the AAP no longer recommends the use of nebulized epinephrine in the treatment of bronchiolitis.²

Hypertonic Saline

Although hypertonic saline (HTS) has been increasingly studied for the treatment of bronchiolitis, the AAP does not recommend its use in the ED. Despite evidence that HTS may reduce hospital length of stay after 24 hours of use in settings where the typical duration of hospitalization exceeds 3 days, it has not been shown to reduce the rate of hospitalization when used in an emergency setting.²

Corticosteroids

While there is good evidence that corticosteroids are beneficial in treating some respiratory diseases, such as asthma and croup, numerous studies have repeatedly failed to show a benefit in treating bronchiolitis. One of the largest studies, a multicenter, randomized, controlled trial of dexamethasone for bronchiolitis by the Pediatric Emergency Care Applied Research Network, did not show any alteration in admission rates, respiratory status after 4 hours of observation, or length of hospital stay.¹² Accordingly, the AAP strongly recommends against the administration of corticosteroids for bronchiolitis in any setting.²

Oxygen Therapy

Oxygen therapy is often necessary in patients with bronchiolitis who demonstrate hypoxia. The definition of hypoxia in this patient population has remained variable. The AAP has established a threshold of oxyhemoglobin saturation (SpO₂) of less than 90% to define hypoxia and has empowered clinicians to not administer oxygen if the SpO₂ exceeds 90%. Based on the oxyhemoglobin dissociation curve, the authors of the AAP guidelines note that when the SpO₂ is less than 90%, small decreases in the arterial partial pressure of oxygen (PaO₂) result in large decreases in the SpO₂. When SpO₂ is greater than 90%, however, large increases in PaO₂ are associated with only small increased in SpO₂. The AAP guidelines note, “In infants and children with bronchiolitis, no data exist to suggest that such increases [in PaO₂ and SpO₂] result in any clinically significant differences in physiologic function, patient symptoms, or clinical outcomes.”²

A relatively new method of administration of oxygen to infants with bronchiolitis is via a humidified, heated, high-flow nasal cannula (HHHFNC). This therapy has been shown to generate continuous positive airway pressure, which improves respiratory effort, reduces the work of breathing, and may decrease the need for intubation.²

Patient Disposition

One of the most challenging tasks for emergency physicians (EPs) is determining the appropriate disposition of infants with bronchiolitis. The variable presentation and dynamic nature of the disease make this particularly difficult. Patients at high risk for apnea should be admitted to the hospital for observation and further care as needed. Admission also should be strongly considered for those with significantly increased work of breathing and tachypnea that does not improve with suctioning—especially when these interfere with feeding. Infants with poor feeding or evidence of dehydration should be admitted to the hospital for intravenous (IV) fluid hydration or nasogastric feedings. Patients with hypoxia (SpO₂ saturations <90%) should also be admitted for supplemental oxygen therapy. It should be noted, however, the AAP recommends “spot-checks” over continuous pulse oximetry in patients who do not require oxygen therapy.²

Another important factor affecting patient disposition is the ability of the caregiver to provide basic patient care and ensure close outpatient follow-up. Prior to discharge, caregivers should be educated on the highly dynamic nature of bronchiolitis and the signs and symptoms that would require prompt return to the ED—especially if the infant has risk factors for the development of severe disease.

Case Conclusion

Based on the patient’s symptoms, history (most notably, the recent incident of sleep apnea at home), and physical examination, the EP quickly identified this infant was at a high risk for both severe bronchiolitis and apnea and required aggressive management. Nasal suctioning was immediately performed to help clear the patient’s secretions; this, however, only slightly improved his RR and work of breathing. Although the infant’s SpO₂ was greater than 90% on room air, the EP administered oxygen via HHHFNC at 6 L per minute, which produced a significant improvement in both RR and effort.

Given the patient’s age and the presence of a fever, a urinalysis was also obtained, the results of which showed no evidence of infection. Since the patient was only able to bottle-feed for a few minutes at a time, the EP initiated IV fluid hydration and contacted the hospitalist team for inpatient admission.

The infant was gradually weaned from HHHFNC on hospital day 2 but remained with suboptimal oral intake for another 24 hours. By hospital day 4, his work of breathing had improved significantly, and he was feeding well with through the assistance of pre-feeding nasal syringe suctioning. The patient was discharged home in the care of his parents later that same day with only mild tachypnea over baseline. At discharge, the EP emphasized the importance of providing close follow-up with their son’s pediatrician. The infant continued to gradually improve as an outpatient, with resolution of nasal congestion by day 12 of his illness; he returned to his baseline breathing and feeding pattern on day 14.

Dr Schneider is a pediatric emergency medicine fellow, Eastern Virginia Medical School, Children’s Hospital of The King’s Daughters, Norfolk. Dr Clingenpeel is a fellowship director of pediatric emergency medicine, and an associate professor of pediatrics, Eastern Virginia Medical School, Norfolk.

Case

An 8-week-old male infant was brought to the ED by his parents after an episode in which it appeared the baby had stopped breathing. The parents stated that while lying on his mother’s lap at home, the patient stopped breathing for approximately 10 to 15 seconds, during which time his face exhibited a bluish color. They further noted that the patient began breathing again after gentle stimulation and had been acting normally since.

The patient was born at 39 weeks gestation via normal vaginal delivery and without any complications. His parents further stated that prior to the cessation of breathing incident, his symptoms of nasal congestion, decreased energy level, and fast breathing had gradually worsened over the past 2 days. The parents also noted that the infant had not been feeding as well over the past 2 days.

Upon arrival, the patient’s vital signs were: heart rate, 140 beats/minute; respiratory rate (RR), 72 beats/minute; and temperature 101.3°F. Oxygen saturation was 92% on room air. On physical examination, the infant had significant rhinorrhea, moderate intercostal and supraclavicular retractions, ausculatory wheezes, and transmitted upper airway noises throughout.

Overview

Bronchiolitis, a disorder caused by a viral lower respiratory tract infection, is the most common lower respiratory infection in children younger than age 2 years.¹ In 2014, the American Academy of Pediatrics (AAP) characterized bronchiolitis as “rhinitis, cough, tachypnea, wheezing, rales, use of accessory muscles, and/or nasal flaring in children under 24 months of age.”² This condition is the most common cause of hospitalization in the first 12 months of life. It is responsible for over 100,000 admissions annually at an estimated cost to the healthcare system of $1.73 billion.³

Etiology and Pathophysiology

Respiratory syncytial virus (RSV) is the most common cause of bronchiolitis. In the United States, the highest incidence of infection occurs during the months of December through March, with some degree of regional variability.⁴ A number of other viruses that can cause bronchiolitis include human metapneumovirus, parainfluenza virus, and influenza virus.¹ Infection with RSV does not grant permanent immunity, and reinfection is common throughout life.²

Pathophysiologically, bronchiolitis is characterized by an invasion of bronchial epithelial cells that lead to to cell death and sloughing into the bronchial lumen. This, coupled with increased mucous production and submucosal edema, leads to a narrowing of the bronchial lumen and obstruction of airflow.⁵

Clinical Manifestations

Bronchiolitis represents a constellation of signs and symptoms beginning with those of an upper respiratory tract infection, including nasal congestion and rhinorrhea with mild cough. On days 3 to 5, the following symptoms develop: tachypnea, wheezing, rales, and signs of respiratory distress (eg, grunting, nasal flaring, inter-/subcostal retractions). Approximately two-thirds of patients will develop a fever.² Recovery tends to begin around days 5 to 7, with the median duration of illness being 12 days.¹ It should be noted that bronchiolitis represents a highly variable and dynamic disease state. Transient episodes of improvement and worsening are common, emphasizing the importance of serial examinations and assessments. Though rare, progression to respiratory failure and death do occur.²

History and Risk Stratification

The focus of the initial history by the clinician should serve two primary purposes. First, it is important to differentiate infants with probable bronchiolitis from those with other disease states having similar clinical manifestations. One of the most challenging diseases to differentiate from bronchiolitis is that of reactive airway disease (RAD). Eliciting a history of allergic rhinitis, eczema, or a family history of asthma may be helpful in determining the precise etiology of the patient’s symptoms. Although no longer recommended for children with bronchiolitis (as will be later discussed), a trial of a bronchodilation may be beneficial in the setting of familial atopy.

The second—and perhaps most important—aspect of patient history is to determine the presence of risk factors for both apnea and the development of severe bronchiolitis. Regarding the risk factors for apnea, Willwerth et al⁶ developed a set of criteria to identify patients at high risk for apnea in the inpatient setting. Patients were considered high risk if they were born at full term and were younger than 1 month of age; if they were born preterm (<37 weeks gestation) and were younger than 48 weeks postconception; and/or if the infant’s parents or a clinician had already witnessed an episode of apnea during the patient’s illness. In this study, all patients who developed apnea were correctly identified by the risk criteria.⁶ Risk factors for severe bronchiolitis include the following: patient age younger than 12 weeks; patient prematurity younger than 37 weeks gestation; and an underlying hemodynamically significant congenital heart disease, chronic lung disease/bronchopulmonary dysplasia, or an immunocompromised state.¹

Diagnosis

In 2014, the AAP updated its guidelines on the diagnosis, management, and prevention of bronchiolitis. One of the strongest statements in these guidelines emphasize that the diagnosis of bronchiolitis should be based almost exclusively on the history and physical examination.² In children younger than age 2 years, historical features such as a viral prodrome, followed by progressively worsening increased respiratory effort and signs and symptoms of lower respiratory-tract disease (eg, wheezing), should guide clinicians to the diagnosis of bronchiolitis. Although nonspecific, physical examination findings such as rhinorrhea, cough, tachypnea, wheezing, rales, and increased respiratory effort—when coupled with a good history—can be beneficial in the diagnosis of bronchiolitis.

Pulse Oximetry

Pulse oximetry has become a standard part of the clinical assessment of patients with bronchiolitis. This is based on data suggesting that pulse oximetry detects hypoxia in cases where it was not suspected on physical examination alone.⁷ However, the effectiveness of pulse oximetry in predicting clinical outcomes is limited. Pulse oximetry should not be used as a proxy for respiratory distress, as studies have shown poor correlation between respiratory distress and oxygen saturations in infants with lower respiratory tract infection.⁸

Radiographic Evaluation

Regarding the diagnosis of bronchiolitis, the AAP notes, “radiographic and laboratory studies should not be obtained routinely.”² While many children with bronchiolitis may have abnormalities on radiographs, there is insufficient data to suggest that chest radiographs correlate with disease severity. In addition, several studies, including a prospective cohort study by Schuh et al,⁹ have shown that infants with suspected lower respiratory tract infections who undergo radiography are more likely to receive antibiotics without any difference in outcomes.

Laboratory Studies

As stated in the AAP guidelines, routine laboratory testing, particularly virologic studies for RSV, have little role in the diagnosis of bronchiolitis. Since numerous viruses can cause bronchiolitis and have similar clinical presentations, the absence of identification of a particular virologic agent does not exclude the diagnosis of bronchiolitis and is moreover unlikely to alter management.

Although routine laboratory evaluation is not recommended in infants with bronchiolitis, one subgroup in which it may be beneficial is in the assessment of serious bacterial infections (SBIs) in febrile infants with bronchiolitis who are younger than 60 days old. Levine et al¹⁰ conducted a large, multicenter, prospective, cross-sectional study of young, febrile infants to determine the risk of SBI in those with RSV bronchiolitis versus those without RSV bronchiolitis. They found that overall febrile infants younger than age 60 days with RSV bronchiolitis have a lower rate of SBI than those without RSV (7% v 12.5%, respectively).¹⁰ In infants between age 28 and 60 days with RSV bronchiolitis, the origin of all SBIs in the study were urinary tract infections. In patients younger than 28 days of age, the risk of developing an SBI was found to be no different between the RSV-positive and RSV-negative groups.¹⁰

Based on the findings in this study, it is recommended that, at the very least, urinalysis for bacterial infection be performed in all infants with RSV bronchiolitis who are younger than age 60 days. Furthermore, since there was no difference in the rates of SBI in patients younger than age 28 days, infants in this age range should undergo a full septic work-up (blood, urine, and cerebrospinal fluid)—regardless of RSV infection status. For infants between ages 28 and 60 days, there is not enough evidence to recommend for or against further laboratory evaluation other than urinalysis.

Treatment

Nasal Suctioning

Nasal suctioning has become the first-line treatment for infants with bronchiolitis. It is used to clear secretions from the nasal passages to aid in respiration, which is particularly important in younger infants—who are obligate nose breathers. Current recommendations are to perform suctioning with increasing respiratory effort, before feeding and before laying the infant down to sleep.¹

Bronchodilators

In the past, bronchodilators such as the β-agonist albuterol have been used to treat bronchiolitis with the idea that bronchial smooth muscle relaxation would improve clinical symptoms. In its 2006 guidelines, the AAP had recommended a trial of albuterol and continuation only if there was a documented objective response. In the 2014 updated guidelines, however, the AAP no longer recommends the use of albuterol in any capacity.

Although several meta-analyses and systematic reviews have demonstrated that bronchodilators may improve clinical symptoms scores, they did not affect disease resolution, need for hospitalization, or length of hospital stay.² In addition, a recent Cochrane systematic review noted no benefit in the clinical course of infants with bronchiolitis treated with bronchodilators, and cited the potential adverse events (tachycardia and tremors) as outweighing any potential benefit.¹¹ In addition to albuterol, the AAP no longer recommends the use of nebulized epinephrine in the treatment of bronchiolitis.²

Hypertonic Saline

Although hypertonic saline (HTS) has been increasingly studied for the treatment of bronchiolitis, the AAP does not recommend its use in the ED. Despite evidence that HTS may reduce hospital length of stay after 24 hours of use in settings where the typical duration of hospitalization exceeds 3 days, it has not been shown to reduce the rate of hospitalization when used in an emergency setting.²

Corticosteroids

While there is good evidence that corticosteroids are beneficial in treating some respiratory diseases, such as asthma and croup, numerous studies have repeatedly failed to show a benefit in treating bronchiolitis. One of the largest studies, a multicenter, randomized, controlled trial of dexamethasone for bronchiolitis by the Pediatric Emergency Care Applied Research Network, did not show any alteration in admission rates, respiratory status after 4 hours of observation, or length of hospital stay.¹² Accordingly, the AAP strongly recommends against the administration of corticosteroids for bronchiolitis in any setting.²

Oxygen Therapy

Oxygen therapy is often necessary in patients with bronchiolitis who demonstrate hypoxia. The definition of hypoxia in this patient population has remained variable. The AAP has established a threshold of oxyhemoglobin saturation (SpO₂) of less than 90% to define hypoxia and has empowered clinicians to not administer oxygen if the SpO₂ exceeds 90%. Based on the oxyhemoglobin dissociation curve, the authors of the AAP guidelines note that when the SpO₂ is less than 90%, small decreases in the arterial partial pressure of oxygen (PaO₂) result in large decreases in the SpO₂. When SpO₂ is greater than 90%, however, large increases in PaO₂ are associated with only small increased in SpO₂. The AAP guidelines note, “In infants and children with bronchiolitis, no data exist to suggest that such increases [in PaO₂ and SpO₂] result in any clinically significant differences in physiologic function, patient symptoms, or clinical outcomes.”²

A relatively new method of administration of oxygen to infants with bronchiolitis is via a humidified, heated, high-flow nasal cannula (HHHFNC). This therapy has been shown to generate continuous positive airway pressure, which improves respiratory effort, reduces the work of breathing, and may decrease the need for intubation.²

Patient Disposition

One of the most challenging tasks for emergency physicians (EPs) is determining the appropriate disposition of infants with bronchiolitis. The variable presentation and dynamic nature of the disease make this particularly difficult. Patients at high risk for apnea should be admitted to the hospital for observation and further care as needed. Admission also should be strongly considered for those with significantly increased work of breathing and tachypnea that does not improve with suctioning—especially when these interfere with feeding. Infants with poor feeding or evidence of dehydration should be admitted to the hospital for intravenous (IV) fluid hydration or nasogastric feedings. Patients with hypoxia (SpO₂ saturations <90%) should also be admitted for supplemental oxygen therapy. It should be noted, however, the AAP recommends “spot-checks” over continuous pulse oximetry in patients who do not require oxygen therapy.²

Another important factor affecting patient disposition is the ability of the caregiver to provide basic patient care and ensure close outpatient follow-up. Prior to discharge, caregivers should be educated on the highly dynamic nature of bronchiolitis and the signs and symptoms that would require prompt return to the ED—especially if the infant has risk factors for the development of severe disease.

Case Conclusion

Based on the patient’s symptoms, history (most notably, the recent incident of sleep apnea at home), and physical examination, the EP quickly identified this infant was at a high risk for both severe bronchiolitis and apnea and required aggressive management. Nasal suctioning was immediately performed to help clear the patient’s secretions; this, however, only slightly improved his RR and work of breathing. Although the infant’s SpO₂ was greater than 90% on room air, the EP administered oxygen via HHHFNC at 6 L per minute, which produced a significant improvement in both RR and effort.

Given the patient’s age and the presence of a fever, a urinalysis was also obtained, the results of which showed no evidence of infection. Since the patient was only able to bottle-feed for a few minutes at a time, the EP initiated IV fluid hydration and contacted the hospitalist team for inpatient admission.

The infant was gradually weaned from HHHFNC on hospital day 2 but remained with suboptimal oral intake for another 24 hours. By hospital day 4, his work of breathing had improved significantly, and he was feeding well with through the assistance of pre-feeding nasal syringe suctioning. The patient was discharged home in the care of his parents later that same day with only mild tachypnea over baseline. At discharge, the EP emphasized the importance of providing close follow-up with their son’s pediatrician. The infant continued to gradually improve as an outpatient, with resolution of nasal congestion by day 12 of his illness; he returned to his baseline breathing and feeding pattern on day 14.

Dr Schneider is a pediatric emergency medicine fellow, Eastern Virginia Medical School, Children’s Hospital of The King’s Daughters, Norfolk. Dr Clingenpeel is a fellowship director of pediatric emergency medicine, and an associate professor of pediatrics, Eastern Virginia Medical School, Norfolk.

References

Joseph M. Evidence-based assessment and management of acute bronchiolitis in the emergency department. Pediatr Emerg Med Pract. 2011;8(3):1-20.
Ralston SL, Lieberthal AS, Meissner HC, et al; American Academy of Pediatrics. Clinical practice guidelines: the diagnosis, management, and prevention of bronchiolitis [Published correction appears in Pediatrics. 2014;134(5):e1474-e1502]. Pediatrics. 2014;134:5 e1474-e1502.
Hasegawa K, Tsugawa Y, Brown DF, Mansbach JM, Camargo CA Jr. Trends in bronchiolitis hospitalizations in the United States, 2000-20009. Pediatrics. 2013;32(1):28-36.
Centers for Disease Control and Prevention (CDC). Respiratory syncytial virus activity—United States, July 2011-January 2013. MMWR Morb Mortal Wkly Rep. 2013;62(8):141-144.
Harper MB, Fleisher GR. Infectious emergencies. In: Fleisher GR, Ludwig S, eds. Textbook of Pediatric Emergency Medicine. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins;2010:916-917.
Willwerth BM, Harper MB, Greenes DS. Identifying hospitalized infants who have bronchiolitis and are at high risk for apnea. Ann Emerg Med. 2006;48(4):441-447.
Shaw KN, Bell LM, Sherman NH. Outpatient assessment of infants with bronchiolitis. Am J Dis Child. 1991;145(2):151-155.
Wang EE, Milner RA, Navas L, Maj H. Observer agreement for respiratory signs and oximetry in infants hospitalized with lower respiratory infections. Am Rev Respir Dis. 1992;145(1):106-109.
Schuh S, Lalani A, Allen U, et al. Evaluation of the utility of radiography in acute bronchiolitis. J Pediatr. 2007;150(4):429-433.
Levine DA, Platt SL, Dayan PS, et al; Multicenter RSV-SBI Study Group of the Pediatric Emergency Medicine Collaborative Research Committee of the American Academy of Pediatrics. Risk of serious bacterial infection in young febrile infants with respiratory syncytial virus infection. Pediatrics. 2004;113(6):1728-1734.
Gadomski AM, Scribani MB. Bronchodilators for bronchiolitis. Cochrane Database Syst Rev. 2014;(6):CD001266.
Corneli HM, Zorc JJ, Majahan P, et al; Bronchiolitis Study Group of the Pediatric Emergency Care Applied Research Network (PECARN). A multicenter, randomized, controlled trial of dexamethasone for bronchiolitis. N Engl J Med. 2007;357(4):331-339.

References

Joseph M. Evidence-based assessment and management of acute bronchiolitis in the emergency department. Pediatr Emerg Med Pract. 2011;8(3):1-20.
Ralston SL, Lieberthal AS, Meissner HC, et al; American Academy of Pediatrics. Clinical practice guidelines: the diagnosis, management, and prevention of bronchiolitis [Published correction appears in Pediatrics. 2014;134(5):e1474-e1502]. Pediatrics. 2014;134:5 e1474-e1502.
Hasegawa K, Tsugawa Y, Brown DF, Mansbach JM, Camargo CA Jr. Trends in bronchiolitis hospitalizations in the United States, 2000-20009. Pediatrics. 2013;32(1):28-36.
Centers for Disease Control and Prevention (CDC). Respiratory syncytial virus activity—United States, July 2011-January 2013. MMWR Morb Mortal Wkly Rep. 2013;62(8):141-144.
Harper MB, Fleisher GR. Infectious emergencies. In: Fleisher GR, Ludwig S, eds. Textbook of Pediatric Emergency Medicine. 6th ed. Philadelphia, PA: Lippincott Williams & Wilkins;2010:916-917.
Willwerth BM, Harper MB, Greenes DS. Identifying hospitalized infants who have bronchiolitis and are at high risk for apnea. Ann Emerg Med. 2006;48(4):441-447.
Shaw KN, Bell LM, Sherman NH. Outpatient assessment of infants with bronchiolitis. Am J Dis Child. 1991;145(2):151-155.
Wang EE, Milner RA, Navas L, Maj H. Observer agreement for respiratory signs and oximetry in infants hospitalized with lower respiratory infections. Am Rev Respir Dis. 1992;145(1):106-109.
Schuh S, Lalani A, Allen U, et al. Evaluation of the utility of radiography in acute bronchiolitis. J Pediatr. 2007;150(4):429-433.
Levine DA, Platt SL, Dayan PS, et al; Multicenter RSV-SBI Study Group of the Pediatric Emergency Medicine Collaborative Research Committee of the American Academy of Pediatrics. Risk of serious bacterial infection in young febrile infants with respiratory syncytial virus infection. Pediatrics. 2004;113(6):1728-1734.
Gadomski AM, Scribani MB. Bronchodilators for bronchiolitis. Cochrane Database Syst Rev. 2014;(6):CD001266.
Corneli HM, Zorc JJ, Majahan P, et al; Bronchiolitis Study Group of the Pediatric Emergency Care Applied Research Network (PECARN). A multicenter, randomized, controlled trial of dexamethasone for bronchiolitis. N Engl J Med. 2007;357(4):331-339.