What is the appropriate evaluation and management for a patient with persistent inspiratory stridor lasting seven months?

Evaluation and Management of Persistent Inspiratory Stridor (7 Months Duration)

For a patient with inspiratory stridor persisting for 7 months, flexible fiberoptic laryngoscopy is the essential diagnostic procedure and should be performed immediately to visualize the airway pathology, followed by rigid bronchoscopy under anesthesia if needed to fully evaluate the subglottis and trachea. 1, 2

Immediate Diagnostic Approach

Primary Evaluation: Flexible Laryngoscopy

• Perform flexible fiberoptic laryngoscopy in the awake patient first to assess dynamic upper airway function, vocal cord mobility, and identify supraglottic pathology such as laryngomalacia, vocal cord paralysis, or glottic webs 1, 2
• This must be done during symptomatic periods, as findings are intermittent and will be normal between episodes 3
• Flexible laryngoscopy allows visualization of the larynx without sedation, preserving the dynamic assessment of airway collapse patterns 1

Secondary Evaluation: Rigid Bronchoscopy

• Direct laryngobronchoscopy under anesthesia with spontaneous breathing is required to definitively evaluate subglottic pathology (stenosis, cysts, hemangiomas) and tracheal abnormalities (tracheomalacia, stenosis) that flexible scopes cannot adequately assess 1
• The relationship between vocal cord length and transsubglottic opening can quantify the degree of narrowing 1
• Both upper and lower airways must be inspected, as anomalies below the epiglottis occur in up to 68% of cases 4

Key Differential Diagnoses for Chronic Stridor

Most Likely: Laryngomalacia

• Laryngomalacia is the most common cause of chronic stridor in infants and children, typically presenting in the first 1-2 months of life with positional symptoms 5, 6
• However, late-onset laryngomalacia can manifest during competitive sports or increased physical activity, particularly if there is a family history of weak voice suggesting inherited structural abnormality 3
• Most cases resolve spontaneously by age 2 years, but severe cases require supraglottoplasty 5, 6

Exercise-Induced Laryngeal Dysfunction (EILD)

• Consider EILD if stridor occurs specifically during exercise with throat tightness and resolves within 5 minutes of stopping activity 3, 4
• Key diagnostic features include flattening of the inspiratory flow-volume loop during symptomatic periods and normal expiratory parameters 3
• This condition is frequently misdiagnosed as asthma, leading to inappropriate corticosteroid overtreatment 3
• Continuous laryngoscopy during exercise challenge is the gold standard for diagnosis 3

Other Structural Causes

• Vocal fold paralysis (unilateral or bilateral) 6
• Subglottic stenosis from prior intubation or congenital narrowing 1
• Subglottic hemangiomas 6
• Tracheomalacia, particularly in patients with history of prematurity or prolonged ventilation 1

Critical Historical and Physical Examination Details

Essential History Elements

• Age of onset and progression pattern: Congenital anomalies present from birth or develop within weeks/months, while acquired causes have later onset 2
• Positional variation: Laryngomalacia worsens with supine positioning and feeding 6
• Exercise relationship: Symptoms during versus after exercise differentiate EILD from exercise-induced bronchoconstriction 3
• Family history of weak voice or laryngeal problems suggests inherited structural abnormality 3
• History of intubation, prematurity, or prolonged ventilation increases risk for subglottic stenosis and tracheomalacia 1
• Response to asthma medications: Failure to respond suggests laryngeal dysfunction rather than lower airway disease 3

Physical Examination Priorities

• Assess severity of respiratory distress: Look for accessory muscle use, tracheal tug, sternal/subcostal/intercostal retractions, and agitation 4, 7
• Characterize the stridor: Inspiratory alone (supraglottic/glottic), expiratory (subglottic/tracheal), or biphasic (severe obstruction at any level) 2, 6
• Evaluate for cyanosis, feeding difficulties, or inadequate weight gain, which indicate severe disease requiring urgent intervention 6

Adjunctive Diagnostic Studies

Pulmonary Function Testing

• Obtain spirometry with flow-volume loops if the patient can cooperate (typically age 3 years and older) 1, 3
• Flattening or truncation of the inspiratory portion indicates variable extrathoracic obstruction, the signature finding of laryngeal dysfunction 3
• Normal expiratory parameters (FEV1, FVC) distinguish laryngeal dysfunction from asthma 3

Imaging Studies

• Imaging is NOT routinely indicated for isolated chronic stridor and should not delay endoscopic evaluation 1
• Consider CT scan only if complications are suspected (abscess, mediastinitis) or if endoscopy findings are inconclusive 1

Management Based on Etiology

For Laryngomalacia

• Conservative management with observation is appropriate for mild cases without feeding difficulties, cyanosis, or growth impairment 5, 6
• Treat concurrent gastroesophageal reflux disease empirically, as posterior laryngeal changes from GERD are common in patients with vocal cord dysfunction 3
• Supraglottoplasty is indicated for severe laryngomalacia with cyanosis, worsening stridor after feeding, or inadequate weight gain 5, 6

For Exercise-Induced Laryngeal Dysfunction

• Speech therapy is the cornerstone of treatment 3
• Beta-2 agonists and asthma medications are ineffective and should be discontinued 3, 4
• If structural laryngomalacia is confirmed on laryngoscopy, supraglottoplasty may be indicated 3

For Subglottic Stenosis or Tracheomalacia

• Rigid bronchoscopy allows therapeutic intervention at time of diagnosis, including balloon dilation or resection of granulation tissue 1
• Severe cases may require tracheostomy or surgical reconstruction 1

Common Pitfalls to Avoid

• Do not assume chronic stridor is benign without endoscopic evaluation, as 7 months duration indicates persistent pathology requiring definitive diagnosis 1, 2
• Do not treat empirically as asthma without confirming lower airway disease, as laryngeal dysfunction will not respond to bronchodilators or corticosteroids 3
• Do not rely on imaging alone—stridor is a visible condition requiring direct visualization 2
• Do not perform laryngoscopy only when asymptomatic, as dynamic abnormalities will be missed 3
• Recognize that up to 20-40% of patients with vocal cord dysfunction also have coexisting asthma, requiring treatment of both conditions 3