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Emergency and Acute Medicine – Bronchiolitis
Overview and Definitions
Bronchiolitis is a lower respiratory tract infection characterized by airway inflammation, bronchoconstriction, wheezing, tachypnea, and varying degrees of respiratory distress, typically preceded by an upper respiratory prodrome.
Etiology and Pathophysiology
Respiratory syncytial virus is responsible for approximately 85–90% of cases. Other causative viruses include influenza, parainfluenza, and adenovirus. Disease incidence peaks during winter months. Viral infection leads to mucosal edema, increased mucus production, and small airway obstruction, resulting in impaired ventilation and increased work of breathing.
Clinical Presentation
Bronchiolitis primarily affects children younger than 2 years, most commonly infants under 1 year. Initial symptoms include nasal congestion with marked rhinorrhea, followed by cough that may be associated with posttussive vomiting. Wheezing, crackles, and rhonchi are common on auscultation. Respiratory distress manifests as tachypnea, nasal flaring, retractions, and grunting, often worsening over 1–3 days. Fever is usually low-grade (<39.5°c). hypoxemia is typically mild, and cyanosis rare. decreased oral intake common, though frank dehydration uncommon. apnea may occur, particularly in premature or very young infants. high-risk children receive monthly intramuscular palivizumab during rsv season to reduce infection risk.< />pan>
Essential Evaluation
Diagnosis is clinical. Assessment focuses on respiratory effort, oxygenation, and hydration status. Pulse oximetry is useful for confirming oxygenation and trending disease progression. Identification of the viral cause may assist with inpatient cohorting but rarely alters acute management.
Diagnostic Tests and Interpretation
Most patients require no laboratory testing beyond pulse oximetry. Nasopharyngeal aspirates or washes for viral studies may be considered in critically ill children, febrile infants under 3 months, those with atypical features, suspected alternative diagnoses (e.g., pertussis or chlamydia), significant comorbidities (chronic lung or cardiac disease), or prematurity. Chest radiographs typically show hyperinflation, peribronchial thickening, atelectasis, or variable infiltrates; atelectasis in young infants suggests more severe disease. Imaging is not routinely indicated and is reserved for atypical presentations, lack of improvement after 2–3 weeks, concern for alternative diagnoses, or impending respiratory failure. Septic evaluation may be required in febrile neonates, and urine testing should be considered in febrile infants 1–3 months old.
Differential Diagnosis
Asthma or recurrent virus-induced wheezing, pertussis (paroxysmal cough without wheeze between spells), bacterial pneumonia (toxic appearance, focal consolidation), foreign body aspiration (sudden onset, often afebrile), and congestive heart failure (feeding difficulty, failure to thrive).
Prehospital Care
Young infants have limited respiratory reserve and may deteriorate rapidly. Continuous cardiorespiratory monitoring and oxygen supplementation are indicated when saturations fall below 90–92% or distress is severe. Vigilance for apnea is critical, especially in infants under 7 weeks, weight <4 kg, or with marked tachypnea comorbidities. bag-mask ventilation may be required for recurrent apneas.< />pan>
Initial Stabilization in the ED
Management follows pediatric advanced life support principles with attention to airway, ventilation, and hydration. Early intubation is indicated for recurrent apnea or impending respiratory failure.
Emergency Department Management
Supplemental oxygen is provided for hypoxemia. Parenteral hydration is used when oral intake is inadequate or respiratory distress is significant. Most children do not benefit from routine pharmacotherapy. Bronchodilators may be trialed in moderate to severe disease, continued only if a clear reduction in work of breathing is observed. Corticosteroids alone generally do not alter outcomes; however, combined nebulized epinephrine with oral dexamethasone may reduce admissions in moderate to severe cases, likely due to synergistic effects. Antibiotics are not indicated unless there is evidence of bacterial infection. Ribavirin has no role in ED management.
Medications
Therapeutic trials may include nebulized albuterol or levalbuterol, nebulized epinephrine, and dexamethasone in selected patients. Most children require no medications, and bronchodilators after discharge are ineffective unless clear benefit was demonstrated prior to discharge.
Disposition
Admission is indicated for hypoxemia requiring oxygen, inability to maintain hydration, significant or persistent respiratory distress, apnea, severe comorbidities, failure to improve after therapy, or unreliable home monitoring. Discharge may be considered when feeding is adequate, oxygenation is acceptable on room air, respiratory distress has resolved, and close follow-up is assured.
Follow-Up Care
Because bronchiolitis often worsens early in its course, close outpatient follow-up within 24 hours is essential. Caregivers should be counseled regarding signs of worsening respiratory distress, dehydration, and apnea. Symptoms may persist for 2–3 weeks, and small, frequent feeds are recommended.
Key Clinical Insights and Common Errors
Infants with bronchiolitis frequently present with a combination of respiratory distress, hypoxia, dehydration, and apnea. Underestimating the potential for rapid deterioration is a common error; vigilant monitoring and early supportive care are critical to preventing adverse outcomes.
Overview and Definitions
Bronchiolitis is a lower respiratory tract infection characterized by airway inflammation, bronchoconstriction, wheezing, tachypnea, and varying degrees of respiratory distress, typically preceded by an upper respiratory prodrome.
Etiology and Pathophysiology
Respiratory syncytial virus is responsible for approximately 85–90% of cases. Other causative viruses include influenza, parainfluenza, and adenovirus. Disease incidence peaks during winter months. Viral infection leads to mucosal edema, increased mucus production, and small airway obstruction, resulting in impaired ventilation and increased work of breathing.
Clinical Presentation
Bronchiolitis primarily affects children younger than 2 years, most commonly infants under 1 year. Initial symptoms include nasal congestion with marked rhinorrhea, followed by cough that may be associated with posttussive vomiting. Wheezing, crackles, and rhonchi are common on auscultation. Respiratory distress manifests as tachypnea, nasal flaring, retractions, and grunting, often worsening over 1–3 days. Fever is usually low-grade (<39.5°c). hypoxemia is typically mild, and cyanosis rare. decreased oral intake common, though frank dehydration uncommon. apnea may occur, particularly in premature or very young infants. high-risk children receive monthly intramuscular palivizumab during rsv season to reduce infection risk.< />pan>
Essential Evaluation
Diagnosis is clinical. Assessment focuses on respiratory effort, oxygenation, and hydration status. Pulse oximetry is useful for confirming oxygenation and trending disease progression. Identification of the viral cause may assist with inpatient cohorting but rarely alters acute management.
Diagnostic Tests and Interpretation
Most patients require no laboratory testing beyond pulse oximetry. Nasopharyngeal aspirates or washes for viral studies may be considered in critically ill children, febrile infants under 3 months, those with atypical features, suspected alternative diagnoses (e.g., pertussis or chlamydia), significant comorbidities (chronic lung or cardiac disease), or prematurity. Chest radiographs typically show hyperinflation, peribronchial thickening, atelectasis, or variable infiltrates; atelectasis in young infants suggests more severe disease. Imaging is not routinely indicated and is reserved for atypical presentations, lack of improvement after 2–3 weeks, concern for alternative diagnoses, or impending respiratory failure. Septic evaluation may be required in febrile neonates, and urine testing should be considered in febrile infants 1–3 months old.
Differential Diagnosis
Asthma or recurrent virus-induced wheezing, pertussis (paroxysmal cough without wheeze between spells), bacterial pneumonia (toxic appearance, focal consolidation), foreign body aspiration (sudden onset, often afebrile), and congestive heart failure (feeding difficulty, failure to thrive).
Prehospital Care
Young infants have limited respiratory reserve and may deteriorate rapidly. Continuous cardiorespiratory monitoring and oxygen supplementation are indicated when saturations fall below 90–92% or distress is severe. Vigilance for apnea is critical, especially in infants under 7 weeks, weight <4 kg, or with marked tachypnea comorbidities. bag-mask ventilation may be required for recurrent apneas.< />pan>
Initial Stabilization in the ED
Management follows pediatric advanced life support principles with attention to airway, ventilation, and hydration. Early intubation is indicated for recurrent apnea or impending respiratory failure.
Emergency Department Management
Supplemental oxygen is provided for hypoxemia. Parenteral hydration is used when oral intake is inadequate or respiratory distress is significant. Most children do not benefit from routine pharmacotherapy. Bronchodilators may be trialed in moderate to severe disease, continued only if a clear reduction in work of breathing is observed. Corticosteroids alone generally do not alter outcomes; however, combined nebulized epinephrine with oral dexamethasone may reduce admissions in moderate to severe cases, likely due to synergistic effects. Antibiotics are not indicated unless there is evidence of bacterial infection. Ribavirin has no role in ED management.
Medications
Therapeutic trials may include nebulized albuterol or levalbuterol, nebulized epinephrine, and dexamethasone in selected patients. Most children require no medications, and bronchodilators after discharge are ineffective unless clear benefit was demonstrated prior to discharge.
Disposition
Admission is indicated for hypoxemia requiring oxygen, inability to maintain hydration, significant or persistent respiratory distress, apnea, severe comorbidities, failure to improve after therapy, or unreliable home monitoring. Discharge may be considered when feeding is adequate, oxygenation is acceptable on room air, respiratory distress has resolved, and close follow-up is assured.
Follow-Up Care
Because bronchiolitis often worsens early in its course, close outpatient follow-up within 24 hours is essential. Caregivers should be counseled regarding signs of worsening respiratory distress, dehydration, and apnea. Symptoms may persist for 2–3 weeks, and small, frequent feeds are recommended.
Key Clinical Insights and Common Errors
Infants with bronchiolitis frequently present with a combination of respiratory distress, hypoxia, dehydration, and apnea. Underestimating the potential for rapid deterioration is a common error; vigilant monitoring and early supportive care are critical to preventing adverse outcomes.
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