Evaluation
Regardless of the etiology of stridor, efforts should be made to keep the patient calm (ie, allow the parent to keep holding a young child, limit any examination not absolutely necessary). Much of the examination can be completed from a distance without disturbing the child.17 Observation of the inspiratory:expiratory (I:E) ratio can localize the level of airway obstruction. For example, an I:E ratio weighted toward a longer inspiration indicates an extrathoracic airway obstruction. Whereas an I:E with a prolonged expiratory phase is consistent with intrathoracic obstruction (eg, terminal bronchial obstruction).17
Another way to localize the level of obstruction is to look for changes in the voice; patients who present with a change in their voice have a subglottic partial obstruction such as croup. However, patients with a muffled voice or drooling have a supraglottic obstruction such as epiglottitis or RPA.17
Management
Management of stridor focuses on reducing airway obstruction, which is usually secondary to edema in the acute setting.
Viral Laryngotracheitis
Oral steroids are the mainstay of treatment. Research has shown dexamethasone is preferred over prednisolone.18-20 Steroids are not only useful in moderate to severe laryngotracheitis but also have a therapeutic role in children with mild laryngotracheitis.18 In hospital settings the parenteral formulation of dexamethasone can be safely given orally with good effect. There is no therapeutic advantage in acute laryngotracheitis to giving dexamethasone via either the IV or intramuscular route vs oral.21 In the outpatient setting, decadron tablets can be crushed and mixed in with a young child’s favorite soft food (eg, mashed potatoes or apple sauce). The authors recommend this strategy in lieu of prescribing dexamethasone suspension as its dilute concentration (1 mg/10 ml) results in a need for a child to receive a relatively large volume of a distasteful liquid. There is a wide therapeutic range of dexamethasone with studies documenting efficacy for laryngotracheitis in doses ranging from 0.15 mg/kg to 0.6 mg/kg. To date there are no large studies which demonstrate routine therapeutic utility of subsequent doses of dexamethasone. Nebulized budesonide (2.5 mg) can be given if oral steroids are not tolerated, however it is significantly more expensive.
Racemic epinephrine is the agent of choice for rapid onset of action in children who demonstrate stridor at rest. It causes vasoconstriction in the laryngeal mucosa, promotes bronchial smooth muscle relaxation, and thinning of bronchial secretions. It offers short-term relief of symptoms until steroids start to work. There is no rebound effect or worsening of symptoms once the epinephrine wears off, but children who receive this drug should be observed in the ED for a period of time (2-3 hours is standard of care in many hospitals) for return of symptoms.10,22 Patients who are persistently symptomatic 4 hours after administration of steroids or who require repeat doses of racemic epinephrine should be admitted for observation.10There are no contraindications to adjuvant treatments, such as antipyretics and non-sedating analgesics. Clinicians should maintain a high index of suspicion for anatomic airway anomalies that may need further evaluation/direct visualization in pediatric patients who present with repeated episodes of croup.10