Overview
Definition:
Bronchiolitis is a common viral lower respiratory tract infection in infants and young children, typically affecting the bronchioles
It is characterized by inflammation, edema, and mucus production, leading to airway obstruction
The most frequent causative agent is the Respiratory Syncytial Virus (RSV).
Epidemiology:
Bronchiolitis affects approximately 10-30% of infants in their first year of life, with peak incidence between 2-6 months of age
It is a leading cause of infant hospitalization and is responsible for a significant proportion of pediatric emergency department visits during the fall and winter months
Incidence rates are higher in premature infants and those with underlying cardiac or pulmonary conditions.
Clinical Significance:
Accurate and timely admission orders for bronchiolitis are crucial for optimizing patient care, preventing complications, and reducing length of stay
For pediatric residents preparing for DNB and NEET SS examinations, understanding the nuances of standard and PRN medication orders, monitoring parameters, and discharge criteria is essential for demonstrating clinical competence and ensuring patient safety.
Clinical Presentation
Symptoms:
Initial symptoms often resemble a common cold: rhinorrhea, cough, and mild fever
Within a few days, symptoms progress to include increased respiratory rate (tachypnea), retractions (subcostal, intercostal, suprasternal), nasal flaring, grunting, and wheezing or crackles on auscultation
Severe cases can manifest as apneic spells, lethargy, and feeding difficulties leading to dehydration.
Signs:
Physical examination findings include tachypnea, increased work of breathing, diffuse expiratory wheezing, and scattered crackles
Oxygen saturation may be reduced (<90-92%)
Palpable liver and spleen may be present due to abdominal breathing
Infants may appear irritable or lethargic, depending on the severity of respiratory distress and hypoxia.
Diagnostic Criteria:
Bronchiolitis is primarily a clinical diagnosis
Diagnostic criteria typically involve characteristic symptoms (cough, wheezing, tachypnea) in an infant or young child (<2 years old) during the typical season, usually accompanied by signs of viral upper respiratory tract infection
While RSV is the most common cause, other viruses like human metapneumovirus, rhinovirus, and adenovirus can also cause bronchiolitis.
Diagnostic Approach
History Taking:
Key history points include onset and duration of symptoms, presence of fever, feeding tolerance, fluid intake and output, history of prematurity, underlying medical conditions (e.g., congenital heart disease, chronic lung disease), and exposure to sick contacts
Red flags include significant prematurity, cyanosis, apneic spells, inability to feed, and severe respiratory distress.
Physical Examination:
A systematic examination focusing on the respiratory system is vital
Assess general appearance, level of consciousness, hydration status, and work of breathing
Auscultate lung fields for wheezing, crackles, and diminished breath sounds
Assess for retractions, nasal flaring, and grunting
Monitor vital signs, including heart rate, respiratory rate, and oxygen saturation
Palpate abdomen for hepatosplenomegaly.
Investigations:
In most cases of mild to moderate bronchiolitis, investigations are not necessary
For severe cases or diagnostic uncertainty, chest X-ray may show hyperinflation, peribronchial thickening, and atelectasis, but it is not required for diagnosis
Nasopharyngeal swab for viral studies (e.g., RSV antigen detection or PCR) can be useful in epidemiological surveillance and for identifying specific pathogens, especially in hospitalized or high-risk infants
Arterial blood gas (ABG) or venous blood gas (VBG) may be indicated in severe respiratory distress to assess for hypoxemia, hypercapnia, or metabolic acidosis.
Differential Diagnosis:
Conditions to consider include pneumonia, asthma exacerbation (in children >2 years), pertussis, foreign body aspiration, cystic fibrosis, and congenital airway abnormalities
Distinguishing features include the age of the patient, presence of high fever, focal lung findings, absence of preceding viral URI symptoms, and response to bronchodilators or antibiotics.
Management
Initial Management:
The primary goals of management are supportive care: ensuring adequate oxygenation, hydration, and comfort
For hospitalized patients, establish IV access for fluid resuscitation if oral intake is compromised
Monitor vital signs, oxygen saturation, and respiratory status closely
Continuous pulse oximetry is standard
Consider supplemental oxygen to maintain saturation >90-92%.
Standard Admission Orders:
Standard admission orders for moderate to severe bronchiolitis typically include: 1
Vital signs and SpO2 monitoring q2-4h
2
Maintain SpO2 >90-92% with supplemental oxygen titration
3
Intravenous fluids at maintenance rate (e.g., D5W with 20mEq/L NaCl at 4-6 ml/kg/hr, adjusted for age and weight) if unable to tolerate oral feeds
4
Strict intake and output monitoring
5
Nasal suctioning as needed, especially before feeds and sleep
6
Consider humidified air or cool mist therapy
7
Elevate head of bed to improve breathing
8
Contact isolation precautions if RSV confirmed.
Prn Medications:
PRN medications are used judiciously: 1
Antipyretics: Acetaminophen (10-15 mg/kg/dose PO/PR q4-6h PRN fever >38.5°C) or Ibuprofen (5-10 mg/kg/dose PO q6-8h PRN fever >38.5°C, for infants >6 months)
2
Bronchodilators: Nebulized Albuterol (Salbutamol) is generally NOT recommended routinely and should only be considered in patients with a clear history of reactive airway disease or if initial trial shows significant improvement in wheezing and respiratory effort
Dosing: 0.15 mg/kg/dose (max 2.5 mg) via nebulizer q4-6h PRN
3
Sedation: Rarely indicated, but consider for severe anxiety or discomfort not responsive to other measures, e.g., Lorazepam 0.05-0.1 mg/kg/dose IV/PO q6-8h PRN, use with extreme caution due to respiratory depressant effects
4
Antivirals: Ribavirin is not recommended for routine bronchiolitis treatment
Palivizumab prophylaxis may be considered for high-risk infants (e.g., premature, severe bronchopulmonary dysplasia, hemodynamically significant congenital heart disease) to prevent RSV lower respiratory tract infections.
Supportive Care:
Nursing care involves meticulous respiratory assessment, frequent suctioning of nasal secretions to maintain airway patency, and close monitoring of fluid balance
Adequate hydration is crucial, with IV fluids provided if oral intake is insufficient
Early recognition of worsening respiratory status or signs of apnea is paramount
Feeding should be encouraged, often in smaller, more frequent amounts
Positioning the infant in a semi-upright position can improve ventilation and reduce work of breathing.
Complications
Early Complications:
Apneic spells, particularly in premature infants or those with neurological impairment
Hypoxemic respiratory failure requiring escalation of care
Dehydration due to poor oral intake
Secondary bacterial pneumonia (rare).
Late Complications:
Increased risk of recurrent wheezing episodes and development of asthma in later childhood
Prolonged respiratory symptoms
Hospital-acquired infections.
Prevention Strategies:
Prophylaxis with palivizumab for eligible high-risk infants
Strict hand hygiene and isolation precautions to prevent nosocomial spread
Educating parents on recognizing warning signs and seeking timely medical attention
Prompt management of dehydration and hypoxia.
Prognosis
Factors Affecting Prognosis:
Prognosis is generally good for most healthy infants, with symptoms typically resolving within 1-3 weeks
Factors influencing a worse prognosis include prematurity, presence of underlying chronic cardiac or pulmonary disease, severe initial presentation with significant hypoxia or apnea, and development of secondary complications
Infants with bronchiolitis are at increased risk of developing recurrent wheezing and asthma later in life.
Outcomes:
Most infants recover fully from bronchiolitis
Hospitalization is usually for supportive care, including oxygen and fluid management
Outcomes depend on the severity of illness and the presence of comorbidities
Mortality is rare in developed countries but can be higher in resource-limited settings or for infants with severe underlying conditions.
Follow Up:
Follow-up is generally not required for uncomplicated bronchiolitis in healthy infants
However, infants with significant underlying conditions or those who required prolonged hospitalization or mechanical ventilation may benefit from follow-up with a pulmonologist or their primary care provider to monitor for long-term respiratory sequelae, such as recurrent wheezing or asthma
Educating parents about potential future respiratory issues is also important.
Key Points
Exam Focus:
Bronchiolitis is a clinical diagnosis in infants <2 years
RSV is the most common pathogen
Supportive care is the cornerstone of management
Routine bronchodilators and steroids are NOT indicated
PRN Albuterol may be tried if there is a history of reactive airway disease or if initial trial shows benefit
Palivizumab is for prophylaxis in high-risk infants
Monitor SpO2 >90-92%.
Clinical Pearls:
Always consider apnea in premature infants with bronchiolitis
Nasal suctioning before feeds and sleep significantly improves comfort and feeding tolerance
Judicious use of PRN Albuterol
if no improvement, discontinue
Recognize signs of dehydration and respiratory distress early
Parents often need reassurance and education about the self-limiting nature of the illness.
Common Mistakes:
Over-reliance on chest X-rays or viral testing for diagnosis
Routine use of bronchodilators or corticosteroids
Inadequate hydration management
Failure to monitor for and manage apneic spells
Discharging infants with significant respiratory distress or hypoxia.