Symptoms of Bronchiolitis in Children
Bronchiolitis presents as a viral upper respiratory prodrome (rhinorrhea, cough) that progresses to lower respiratory tract symptoms including tachypnea, wheezing, rales, and increased work of breathing manifested by grunting, nasal flaring, and intercostal/subcostal retractions. 1
Clinical Presentation Pattern
The illness follows a characteristic two-phase pattern:
Initial Phase (Upper Respiratory Symptoms)
- Rhinorrhea (runny nose)
- Cough
- Fever (may be present)
- Nasal congestion
These symptoms typically last 2-4 days before progression 2.
Progressive Phase (Lower Respiratory Symptoms)
- Tachypnea (rapid breathing)
- Wheezing
- Rales (crackles on lung examination)
- Increased respiratory effort including:
- Grunting
- Nasal flaring
- Intercostal retractions (pulling between ribs)
- Subcostal retractions (pulling below ribcage)
- Decreased oxygen saturation
- Feeding difficulties
- Dehydration (from poor oral intake)
Age-Specific Considerations
This condition primarily affects children younger than 2 years of age, with peak incidence between 1-6 months 1, 3. The American Academy of Pediatrics guidelines specifically address children from 1 month through 23 months 1.
Critical Warning Signs
Apnea Risk
Apnea (breathing pauses) can occur, particularly in:
- Infants under 1 month of age
- Premature infants less than 48 weeks postconceptional age
- Those with prior apneic events 1
Severity Indicators
Assess for signs suggesting severe disease:
- Respiratory rate ≥70 per minute (tachypnea threshold associated with increased severity risk)
- Altered mental status
- Inability to feed or maintain hydration
- Significant retractions and work of breathing
- Oxygen desaturation 1
High-Risk Features to Identify
The following underlying conditions increase risk of severe disease and should be specifically assessed 1:
- Age less than 12 weeks
- History of prematurity
- Chronic lung disease (bronchopulmonary dysplasia)
- Hemodynamically significant congenital heart disease
- Immunodeficiency
- Neuromuscular disease
- In utero smoke exposure
Temporal Course
The disease is variable and dynamic, typically worsening over 3-4 days before spontaneous improvement 4. Serial observations may be necessary to fully assess the child's status, as symptoms fluctuate 1.
Common Pitfall
Do not confuse bronchiolitis with asthma or reactive airway disease. Bronchiolitis is specifically a viral lower respiratory tract infection in young children (under 2 years) with a characteristic prodrome followed by wheezing and respiratory distress 1. The most common causative agent is respiratory syncytial virus (RSV), with 90% of children infected in the first 2 years of life 1.