Tracheomalacia/laryngomalacia

Select 5-Minute Pediatrics Topics

Tracheomalacia/laryngomalacia

Description

  • Laryngomalacia:
    • Narrowing and collapse of the supraglottic structures of the larynx
    • Most common congenital anomaly of the larynx
    • Most common noninfectious cause of stridor in children
  • Tracheomalacia:
    • Narrowing and collapse of the extrathoracic or intrathoracic trachea
    • Common cause of chronic wheezing in infants and children
    • Classified as primary or secondary:
      • Primary: Congenital; results from immature development of the tracheal structures; may occur with other congenital anomalies such as tracheoesophageal fistula, laryngomalacia, and facial anomalies
      • Secondary: Acquired in a normally developed trachea after some insult such as prolonged positive pressure ventilation, recurrent infection or aspiration, or external compression

Etiology

  • Laryngomalacia:
    • Multiple factors likely involved
    • Inward collapse of aryepiglottic folds (cuneiform cartilages) during inspiration
    • Elongated, flaccid, omega-shaped epiglottis prolapses posteriorly into the pharynx during inspiration
    • Immaturity of the laryngeal cartilage results in weakness and collapse during inspiration.
    • Immaturity of neuromuscular control results in hypotonia of pharyngeal muscles.
  • Tracheomalacia:
    • Weakness of the tracheal wall secondary to softening of the anterior cartilaginous rings and to decreased tone of the posterior membranous wall
    • During exhalation, increased collapsing pressure across a compliant airway wall causes invagination of the posterior membrane.
    • With increasing age, the length, area, thickness, and amount of cartilage increases in the anterior rings, as well as the size and contractility of the membranous wall.

Signs and Symptoms

History

  • Laryngomalacia:
    • Symptoms may be present at birth or delayed until 1–2 months of age.
    • Inspiratory stridor
    • May be asymptomatic during sleep or quiet breathing
    • Worsens with crying, agitation, feeding, upper respiratory infections, supine positioning
  • Tracheomalacia:
    • Primary: Symptoms may be delayed until 2–3 months of age.
    • Secondary: Symptoms delayed until after causative insult occurs
    • Expiratory wheeze (or inspiratory stridor if extrathoracic trachea involved)
    • Harsh barking cough
    • May be asymptomatic during sleep or quiet breathing
    • Worsens with crying, agitation, feeding, and upper respiratory infections

Physical Exam
  • Laryngomalacia:
    • High-pitched or vibratory, low-pitched inspiratory stridor
    • Suprasternal retractions
    • Positional changes noted: Usually worsens with flexion of neck, supine position
    • Stridor transmitted throughout the chest on auscultation
  • Tracheomalacia:
    • Homophonous expiratory wheeze (intrathoracic)
    • High-pitched inspiratory stridor (extrathoracic)
    • Intercostal retractions, worse during acute respiratory infections

Tests

  • Flexible fiberoptic laryngo/bronchoscopy:
    • Performed during spontaneous breathing
    • Most efficient method to evaluate stridor or chronic wheezing
    • Visualize the degree and extent of laryngomalacia and/or tracheomalacia.
    • Evaluate for other airway lesions in the differential diagnosis.
  • Barium swallow:
    • Best noninvasive test to evaluate stridor or chronic wheeze
    • Especially of value in evaluation of patients with concomitant swallowing abnormalities
    • May see external compression of esophagus from vascular malformation
  • Chest radiograph:
    • Usually normal in both laryngomalacia and tracheomalacia
    • Important to rule out other causes of chronic cough or abnormalities that may cause external airway compression
  • Airway fluoroscopy:
    • Lateral views are the most useful to visualize the defect.
    • May be normal; does not rule out diagnosis
    • Inspiratory collapsing larynx may be seen in laryngomalacia.
    • Expiratory narrowing or collapse of the trachea may be seen in tracheomalacia.
  • MRI:
    • Evaluates for thoracic/vascular anomalies that may cause external compression of the airway
    • May provide more precise measurements of airway size
    • May be performed dynamically to show changes in airway caliber during respiratory cycle

Differential Diagnosis

  • Laryngomalacia: Differential diagnosis of chronic stridor:
    • Abnormalities of the vocal cords: Vocal cord paralysis
    • Laryngeal abnormalities: Laryngeal cleft, laryngeal web, subglottic hemangioma, papilloma
    • Subglottic stenosis (biphasic stridor)
  • Tracheomalacia: Differential diagnosis of chronic homophonous wheeze:
    • Structural abnormalities: Vascular compression/ring, tracheal stenosis/web, cystic lesion, mass/tumor
    • External compression from mediastinal mass, vascular ring
    • Nonstructural abnormalities: Gastroesophageal reflux disease, retained foreign body, chronic bacterial bronchitis

ALERT
  • Do not miss other causes for presenting symptoms (see “Differential Diagnosis” above).
  • Investigate lower airway in more severe cases of laryngomalacia for other airway anomalies.
  • Treat diseases that may exacerbate symptoms and delay spontaneous resolution.
  • The use of bronchodilators (β2-agonist) may increase the tracheal wall collapsibility by decreasing muscular tone, thereby making the symptoms worse.
  • Bronchoscopy should ideally be done under conscious sedation during spontaneous breathing to avoid altering vocal cord movement and airway dynamics.
  • The use of rigid bronchoscopy may stent open the trachea, making tracheomalacia more difficult to identify.

General Measures

  • Laryngomalacia:
    • Usually resolves spontaneously by 15–18 months of age
    • Observation and reassurance
    • Treatment of exacerbating factors, such as upper respiratory infections, asthma, or gastroesophageal reflux disease
    • Tracheostomy may be needed in severe cases to bypass airway obstruction.
    • In rare situations, laryngeal surgery is necessary: Epiglottoplasty, resection of arytenoids
  • Tracheomalacia:
    • Usually resolves spontaneously by 18–24 months of age
    • Observation and reassurance
    • Treatment of exacerbating factors, such as upper respiratory infections, asthma, or gastroesophageal reflux disease
    • Bronchoconstrictor therapy to increase tone of airway wall: Bethanechol chloride, ipratropium bromide
    • Continuous positive airway pressure may be needed in more severe cases.
    • Tracheostomy may be needed in severe cases to bypass lesion or to provide continuous positive airway pressure.
    • Humidification of secretions may help some patients, especially during respiratory infections.
    • Aortopexy may be needed in severe cases to suspend the anterior trachea and widen the airway.

Monitor for recurrent respiratory symptoms, poor growth, other exacerbating conditions (asthma, gastroesophageal reflux disease)

Prognosis

  • In cases of isolated laryngomalacia and/or tracheomalacia, prognosis is usually excellent.
  • In patients with history of tracheoesophageal fistula, vascular ring, or other airway anomalies, tracheal dysfunction may persist after corrective surgery.

ICD-9

748.3 Other anomalies of larynx, trachea, and bronchus

FAQ

  • Q: When will the symptoms improve?
  • A: As anatomic structures mature with age, laryngomalacia symptoms may improve by 6 months of age with usual resolution by 18 months of age. Tracheomalacia may last longer, but in both entities symptoms usually resolve completely by age 2 years.
  • Q: Should all patients have an endoscopic evaluation?
  • A: No. Diagnosis is usually made based on the appropriate history and physical examination. Infants with mild to moderate typical presentation need only careful monitoring for recurrence or worsening of symptoms and for poor growth. However, airway evaluation should be performed in all cases where a different pathology is considered or when symptoms worsen or persist past the expected age of resolution.
  • Q: What should I do when symptoms worsen?
  • A: Calm the patient; provide humidification of secretions and treatment of intercurrent infection. In cases where associated bronchospasm is suspected, a trial of steroids or bronchodilators may be considered.Calm the patient; provide humidification of secretions and treatment of intercurrent infection. In cases where associated bronchospasm is suspected, a trial of steroids or bronchodilators may be considered.

AUTHOR

Ronn E. Tanel, MD

BIBLIOGRAPHY

  1. Austin J , Ali T. Tracheomalacia and bronchomalacia in children: Pathophysiology, assessment, treatment and anaesthesia management. Paediatr Anaesth. 2003;13:3–11.
  2. Carden KA , Boiselle PM , Waltz DA , et al. Tracheomalacia and tracheobronchomalacia in children and adults: An in-depth review. Chest. 2005;125:984–1005.
  3. Daniel SJ. The upper airway: Congenital malformations. Paediatr Respir Rev. 2006;7:S260–S263.
  4. Jaquiss RD. Management of pediatric tracheal stenosis and tracheomalacia. Semin Thorac Cardiovasc Surg. 2004;16:220–224.
  5. Sichel JY , Dangoor E , Eliashar R , et al. Management of congenital laryngeal malformations. Am J Otolaryngol. 2000;21:22–30.
  6. Wright CD. Tracheomalacia. Chest Surg Clin North Am. 2003;13:349–357, viii.