Overview
Definition:
Bronchiolitis is a common acute viral infection of the lower respiratory tract that affects infants and young children, characterized by inflammation and obstruction of the bronchioles
It is typically caused by the Respiratory Syncytial Virus (RSV), but other viruses can also be implicated
The hallmark is wheezing and respiratory distress due to mucus production and airway narrowing.
Epidemiology:
Bronchiolitis is the most common lower respiratory tract infection in infants under one year of age, with a peak incidence between 2 and 6 months
It accounts for a significant number of hospital admissions in this age group
Outbreaks usually occur during the winter months
Factors increasing risk include prematurity, congenital heart disease, and lack of breastfeeding.
Clinical Significance:
Understanding bronchiolitis management, particularly supportive care measures like suctioning and hydration, is crucial for pediatric residents preparing for DNB and NEET SS exams
Effective strategies can prevent complications, reduce hospital stays, and improve patient outcomes
Mismanagement can lead to significant morbidity and mortality.
Clinical Presentation
Symptoms:
Initial symptoms often mimic the common cold: rhinorrhea
Followed by cough
Gradual onset of tachypnea
Increasing difficulty feeding
Intercostal and subcostal retractions
Nasal flaring
Grunting respirations
Fever may be present but is often low-grade
Irritability and lethargy may indicate more severe disease.
Signs:
Wheezing on auscultation, often expiratory
Crackles or rales may also be heard
Nasal congestion and copious clear rhinorrhea
Signs of respiratory distress: tachypnea, tachycardia, retractions
Possible cyanosis in severe cases
Dehydration can be evident by decreased urine output and dry mucous membranes.
Diagnostic Criteria:
Diagnosis is primarily clinical, based on the characteristic signs and symptoms in infants and young children, typically <2 years old
Laboratory investigations are generally not required for diagnosis
Viral testing (e.g., RSV antigen detection) may be used in specific situations, such as during an outbreak or for epidemiological studies, but does not usually alter management.
Diagnostic Approach
History Taking:
Detailed history of onset and progression of symptoms
Exposure to sick contacts
Preexisting medical conditions (e.g., prematurity, cardiac disease)
Feeding history and fluid intake
Birth history
Parental concerns regarding breathing difficulty
History of allergies or asthma in family
Red flags: poor feeding, lethargy, apnea, severe respiratory distress.
Physical Examination:
Assess general appearance: alert, active, or distressed
Vital signs: temperature, heart rate, respiratory rate, oxygen saturation
Thorough respiratory exam: auscultation for breath sounds, wheezes, crackles
observe for retractions, nasal flaring, accessory muscle use
Evaluate hydration status: mucous membranes, skin turgor, fontanelle, urine output
Assess for neurological status and alertness.
Investigations:
Routine investigations are generally not indicated in otherwise healthy infants with mild to moderate bronchiolitis
Chest X-ray may show hyperinflation, peribronchial thickening, or atelectasis, but findings are often nonspecific and do not change management
Arterial blood gas (ABG) or venous blood gas may be considered in severely ill infants to assess oxygenation and ventilation
Complete blood count (CBC) and electrolytes are usually not necessary unless there is a concern for sepsis or severe dehydration.
Differential Diagnosis:
Other causes of wheezing and respiratory distress in infants: asthma (less common in infants <1 year), pneumonia, bacterial bronchitis, foreign body aspiration, congenital airway abnormalities, gastroesophageal reflux with aspiration, cystic fibrosis (rare presentation)
Distinguishing features include abrupt onset for foreign body, persistent fever for pneumonia, and history of recurrent infections for cystic fibrosis.
Management
Initial Management:
The cornerstone of management is supportive care
Assess airway, breathing, and circulation (ABC)
Supplemental oxygen to maintain SpO2 > 90-92%
Maintain adequate hydration
Nasal suctioning to clear secretions
Monitor respiratory status closely
Hospitalization is indicated for severe respiratory distress, hypoxemia, apnea, dehydration, or inability to feed orally.
Medical Management:
Bronchodilators (e.g., albuterol) are generally not recommended for routine use in bronchiolitis as they are often ineffective and can even exacerbate symptoms in some children
Corticosteroids are also not recommended
Antibiotics are not indicated unless there is a concomitant bacterial infection, which is rare
Antiviral therapy (e.g., ribavirin) is reserved for very specific, severely immunocompromised patients or those with severe RSV infection requiring mechanical ventilation and is not standard care.
Hydration Strategies:
Maintain adequate fluid intake to prevent dehydration and thin secretions
For infants who can tolerate oral feeds, offer small, frequent feeds
If oral intake is insufficient, intravenous (IV) fluids may be necessary
Aim for adequate urine output (1-2 mL/kg/hr)
Avoid overhydration
Monitor electrolyte balance if IV fluids are administered for extended periods.
Suctioning Techniques:
Nasal suctioning is important to remove secretions that contribute to airway obstruction and feeding difficulties
Gentle bulb suctioning can be performed before feeds and sleep
Saline nasal drops or spray can help loosen thick mucus before suctioning
Avoid aggressive or frequent suctioning, which can cause mucosal irritation and edema
If nasopharyngeal suctioning is required for significant secretions, it should be performed gently and with caution, preferably before oxygen administration or feeding.
Supportive Care:
Close monitoring of vital signs and respiratory status is paramount
Elevate the head of the bed to ease breathing
Provide a humidified environment, though the benefit of routine humidification is debated
Manage fever with antipyretics (e.g., acetaminophen, ibuprofen) as needed
Educate parents on signs of worsening respiratory status and when to seek medical attention.
Complications
Early Complications:
Apnea, particularly in premature infants or those with neuromuscular compromise
Hypoxemia
Dehydration
Bacterial superinfection (rare)
Respiratory failure requiring mechanical ventilation.
Late Complications:
Increased risk of recurrent wheezing episodes and asthma later in childhood
Persistent pulmonary issues in infants with underlying chronic lung disease or congenital heart disease.
Prevention Strategies:
Prompt and effective supportive care, including vigilant monitoring, adequate hydration, and appropriate suctioning
Early recognition of respiratory deterioration
Prevention of RSV infection through hygiene measures (handwashing) and Palivizumab prophylaxis for high-risk infants
Parental education on recognizing warning signs.
Prognosis
Factors Affecting Prognosis:
Severity of initial illness
Age and gestational age at onset
Presence of underlying medical conditions (e.g., prematurity, congenital heart disease, chronic lung disease)
Degree of respiratory distress and hypoxemia
Promptness and adequacy of supportive care.
Outcomes:
Most infants recover fully from bronchiolitis within 7-10 days, though cough may persist for several weeks
Mortality is low in developed countries, primarily affecting infants with severe underlying comorbidities
Hospitalization duration varies with severity and response to treatment.
Follow Up:
Routine follow-up is generally not required for uncomplicated bronchiolitis in healthy infants
However, infants with significant risk factors or complications may benefit from follow-up to assess for long-term respiratory sequelae or to manage exacerbations of underlying conditions
Educate parents on signs of recurrence or potential for developing asthma.
Key Points
Exam Focus:
Bronchiolitis is a clinical diagnosis
RSV is the most common cause
Supportive care is the mainstay: oxygen, hydration, and suctioning
Bronchodilators and steroids are NOT routinely indicated
Apnea is a critical complication, especially in neonates and prematures
Differentiate from asthma in infants.
Clinical Pearls:
Gentle nasal suctioning before feeds and sleep can significantly improve comfort and feeding
Monitor oxygen saturation diligently
Be vigilant for signs of dehydration
Educate parents on home care and warning signs
Remember that wheezing alone does not equal asthma in infants <1 year.
Common Mistakes:
Overuse of bronchodilators or steroids
Aggressive suctioning leading to mucosal edema
Inadequate fluid management leading to dehydration
Failing to recognize and manage apnea promptly
Misinterpreting nonspecific chest X-ray findings as definitive for bacterial pneumonia.