Steeple Sign in Pediatric Patients
Clinical Significance
The steeple sign is a characteristic radiographic finding on anteroposterior neck X-ray indicating subglottic narrowing in viral croup (laryngotracheobronchitis), the most common cause of acute upper airway obstruction in children. 1, 2
The steeple sign represents narrowing of the subglottic trachea, creating a church steeple or pencil-point appearance on radiograph, distinguishing croup from other causes of stridor. 1
Diagnostic Approach
Clinical Presentation
- Barking cough, inspiratory stridor, and hoarseness are the classic triad of croup, typically preceded by viral upper respiratory symptoms 3, 4, 1
- Stridor location provides anatomic clues: inspiratory stridor suggests supraglottic obstruction, expiratory stridor indicates lower tracheal obstruction, and biphasic stridor suggests glottic or subglottic lesions 2
- Voice changes indicate laryngeal involvement 2
Critical Red Flags Requiring Immediate Intervention
- Severe respiratory distress with chest retractions, grunting, nasal flaring, tracheal tugging, or severe tachypnea indicates impending respiratory failure 5, 3
- Head nodding in synchrony with respiration represents severe respiratory distress from sternocleidomastoid and scalene muscle contraction, not benign movement 5, 6
- Failure to improve with standard croup treatment (dexamethasone and nebulized epinephrine) within 2-3 hours suggests alternative diagnosis or severe disease 3, 4, 7
Differential Diagnosis Considerations
- Atypical presentations warrant consideration of neurological causes, foreign body aspiration, bacterial tracheitis, or epiglottitis 7, 2
- Absence of viral prodrome, drooling, toxic appearance, or rapid deterioration suggest non-viral etiologies 7, 2
- Nasofibroscopy should be performed when clinical presentation is atypical or fails to respond to standard therapy 7
Management Protocol
Immediate Treatment for All Croup Patients
All children presenting to emergency departments with croup should receive oral dexamethasone 0.6 mg/kg (maximum 10 mg) immediately without delay. 4 Evidence supports that 0.15 mg/kg may be equally effective, though 0.6 mg/kg remains standard 4
Severity-Based Escalation
- Mild croup (no stridor at rest): Dexamethasone alone, observe 2-3 hours, discharge if stable 4
- Moderate to severe croup (stridor at rest, retractions): Add nebulized racemic epinephrine (0.5 mL of 2.25% solution in 3 mL saline) 3, 4
- Post-epinephrine observation: Mandatory 2-3 hour observation period due to rebound effect risk; patients stable after this period can be safely discharged 4
Escalation to Critical Care
- Patients requiring repeated epinephrine doses, showing progressive respiratory distress despite treatment, or developing acute respiratory failure require PICU admission 3
- Endotracheal intubation and mechanical ventilation may be necessary for life-threatening cases, particularly with emerging SARS-CoV-2 variants causing severe croup 3
- Duration of intubation in severe cases typically ranges 80-112 hours 3
Common Pitfalls to Avoid
- Do not rely on humidified air therapy alone—its efficacy has not been established 4
- Do not assume all stridor is benign croup—neurological causes can present similarly but require entirely different management 7
- Do not discharge patients immediately after epinephrine administration—the 2-3 hour observation period is mandatory to detect rebound deterioration 4
- Do not miss signs of severe respiratory distress (head nodding, grunting, severe retractions) which indicate impending respiratory failure requiring immediate intervention 5, 3
- Do not delay steroids for radiographic confirmation—treatment should begin based on clinical presentation 4
Emerging Considerations
Recent evidence demonstrates that SARS-CoV-2 omicron BA.2 variant can cause life-threatening croup unresponsive to conventional therapy, even in previously healthy children without underlying disease 3. This represents a departure from traditional croup management expectations and warrants heightened vigilance during viral surges 3.