Laryngomalacia and Tracheomalacia


Laryngomalacia


Laryngomalacia


Tracheomalacia

Malacia is derived from Greek “malakia” meaning soft.  In terms of respiratory disease, softening of the airway leads to narrowing or collapse during part of the respiratory cycle.

 

Tracheomalacia

Pathophysiology – expiratory collapse of the intrathoracic airway, due to defective cartilaginous support.  During expiration, positive intrathoracic pressure relative to the airway lumen leads to dynamic collapse of structures with anatomic deformity.

Differential – bronchiolitis, asthma, external compression (type 2 lesions)

Clinical presentation - expiratory stridor or wheezing is most common as trachea is primarily intrathoracic.  In comparison to asthma, wheezing sound is centrally located, low-pitched and homophonous.  Exacerbated with activity, URIs.  Symptoms lessen when prone, and at rest.

Type 1 – congenital 2/2 abnormal development (TE fistula, esophageal atresia, polychondritis)

Type 2 – acquired 2/2 extrinsic compression (vascular rings, cystic hygromas, tumors)

Type 3 – acquired 2/2 irritation/inflammation (intubation, GERD)

Generally benign, and self-resolving with age and maturation of airway structures; conservative management is usually indicated (chest PT, humidified O2 and treatment of infections).  There may be a relatively higher incidence of respiratory illness due to poor mucociliary function, as well as more pronounced symptoms and protracted course of illnesses.  If PFTs are performed, mean PEF, FEV1 and FEV1/FVC are below expected, and do not respond to bronchodilators (vs. asthma).

A more severe course is indicated by increased work of breathing, desaturation, failure to thrive and delayed development.  Periodic episodes of apnea, cyanosis, and respiratory arrest (“death spells”) are due to V/Q mismatch, and require imaging for further evaluation and to dictate treatment.  Additionally, compression of the trachea by a full esophagus may lead to arterial desaturation and periodic respiratory obstruction.  Unrecognized or misdiagnosed, severe tracheomalacia can have significant mortality due to respiratory or cardiovascular arrest.

Options beyond conservative management include ipratropium bromide, bethanechol, tracheal stents, nasal CPAP, aortopexy, and tracheostomy.

  • R Boogaard et al. Tracheomalacia and Bronchomalacia in Children: Incidence and Patient characteristics. Chest 2005;128;3391-3397
  • KA Carden et al. Tracheomalacia and Tracheobronchomalacia in Children and Adults: An in-depth review. Chest 2005;127;984-1005
  • IB Masters. Congenital Airway Lesions and Lung Disease. Pediatr Clin N Am 56 (2009) 227–242

 

Laryngomalacia

 Most common cause of stridor in infants, click for example

Pathophysiology – inspiratory collapse of supraglottic structures, such as arytenoids and epiglottis, due to anatomic or functional abnormalities.  During inspiration, pressure within the extrathoracic large airways (and thorax) is negative relative to atmosphere, leading to collapse of structures with inadequate structural support. 

Differential – includes lingual cysts, vascular slings/rings, vocal cord disorders and hemangiomas.  Concomitant symptoms (such as swallowing difficulties, chronic cough, and cutaneous or neurologic manifestations) may indicate a congenital syndrome.

Etiology – most cases are congenital, but some may be associated with other conditions such as GERD, neuromuscular weakness or as part of a congenital syndrome.  A typical anatomic classification scheme is described below, however clinical judgment as to the severity of the obstruction and impact on growth and development may be more useful in guiding therapy. 

Type 1: prolapse of mucosa onto arytenoids

Type 2: foreshortened aryepiglottic folds

Type 3: posterior displacement of the epiglottis

Clinical presentation & course – Inspiratory stridor, usually presents during the first 2 weeks of life, worsens up to 6 months and resolves between 1-2 years of age.  Symptoms may be lessened when the child is in the prone position, as the excess tissue falls away from the airway.  Stridor is exacerbated during viral infection, crying or agitation.  Diagnosis may be clinical, or with bronchoscopy to rule out other disorders.

Mild laryngomalacia is an isolated, intermittent inspiratory stridor, accompanied by normal growth and development.  Reassurance and follow-up are important to ensure resolution.

Moderate laryngomalacia is continual stridor and increased work of breathing, again with normal growth and development.  Frequent follow-up and parental reassurance is indicated to ensure spontaneous resolution.

Severe laryngomalacia also has continual stridor and increased work of breathing, accompanied by respiratory failure requiring oxygen or airway support, developmental delay and/or failure to thrive.  Surgery (supraglottoplasty) is often indicated to reduce the work of breathing, and typically negates the need for tracheostomy.

 

References

  1. Kliegman: Nelson Textbook of Pediatrics, 18th ed.; Chapter 383 - Congenital Anomalies of the Larynx, Trachea, and Bronchi
  2. IB Masters. Congenital Airway Lesions and Lung Disease. Pediatr Clin N Am 56 (2009) 227–242
  3. Paston, Francine and Bye, Michael. Tracheomalacia. Pediatrics in Review September 1996
  4. Vicencio A and Parikh S. Laryngomalacia and Tracheomalacia: Common Dynamic Airway Lesions. Pediatrics in Review April 2006

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