Diagnosing Bronchiolitis: A Clinical Approach
Bronchiolitis is a clinical diagnosis based solely on history and physical examination—no laboratory tests or imaging studies are needed for typical presentations. 1
Clinical Presentation
The diagnosis requires identifying this constellation of findings in children under 2 years of age: 1
- Viral upper respiratory prodrome (rhinorrhea, congestion, sneezing) followed by lower respiratory tract involvement 1, 2
- Lower respiratory signs: tachypnea, wheezing, rales, cough 1
- Increased respiratory effort: grunting, nasal flaring, intercostal/subcostal retractions 1
Key History Elements
Assess these specific factors during evaluation: 1
Physical Examination Specifics
Serial observations over time are often necessary as the disease state varies considerably: 1
- Count respiratory rate for a full 60 seconds for accuracy 1
- Tachypnea ≥70 breaths/minute suggests increased risk of severe disease 1
- Suction the nose and position the infant before examining, as upper airway obstruction affects assessment 1
- Assess for apnea, particularly in young infants and those with prematurity 1
When NOT to Order Tests
Do not routinely obtain: 1
- Chest radiographs - not helpful for diagnosis and may lead to unnecessary antibiotic use 1
- Laboratory studies (complete blood counts, viral testing) - rarely alter management 1
- RSV testing - does not change clinical management in typical cases 1
Exceptions for Testing
Consider imaging or labs only when: 1
- The child fails to improve at the expected rate 1
- Disease severity requires further evaluation 1
- Another diagnosis is suspected 1
Common Pitfall
The American Academy of Pediatrics emphasizes that routine diagnostic testing increases costs without improving outcomes and may lead to inappropriate antibiotic prescribing when radiographs show infiltrates that are actually atelectasis, not bacterial pneumonia. 1