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Stridor - upper airway obstruction in neonates

Key messages

  • All newborns with stridor need evaluation of their airway because of the risk of significant airway obstruction.
  • The small size and underdevelopment of the neonatal airway make it more vulnerable to the effects of either extrinsic compression or intrinsic obstruction.
  • The causes of upper airway obstruction are best considered according to their location.

Stridor is a loud, high pitched respiratory sound usually heard on inspiration but it can occur on expiration in severe upper airway obstruction.

The upper airway

The upper airway can be divided into 3 segments:

Characteristics of the newborn airway

Characteristics of the newborn airway:

Both of these characteristics make the newborn airway more vulnerable to the effects of either extrinsic compression or intrinsic obstruction.

Obstruction of the upper airway

Note:

Signs and symptoms of obstruction

Associated signs and symptoms of obstruction include:

Differential diagnosis

The causes of upper airway obstruction are best considered according to their location.

1. Supraglottic

Obstruction in this segment produces an inspiratory stridor.

Choanal atresia

Choanal atresia, a narrowing or blockage of the nasal area, is the most common congenital anomaly of the nose. Issues to note:

Micrognathia

Micrognathia is a small lower jaw (eg Pierre-Robin sequence, Treacher-Collins syndrome). Issues to note:

Macroglossia

Macroglossia is an abnormally large tongue. Issues to note:

Lingual thyroid

A lingual thyroid results from failure of descent of the thyroid gland from its embryological origin at the base of the tongue via the thyroglossal duct. Issues to note:

2. Glottic (laryngeal) and subglottic

A biphasic stridor is typically associated with obstruction in this region.

Laryngomalacia

Laryngomalacia is the most common cause of chronic stridor. Issues to note:

Vocal cord paralysis

Vocal cord paralysis is the second most common cause of stridor in infants. Issues to note:

Subglottic (or tracheal) stenosis

Issues to note about subglottic (or tracheal) stenosis:

A laryngeal web

A laryngeal web is failure of the embryonic airway to recanalise. Issues to note:

Cystic hygroma

Issues to note about cystic hygroma:

Subglottic haemangiomata

Issues to note about subglottic haemangiomata:

Laryngotracheo-oesophageal cleft

Issues to note about laryngotracheo-oesophageal cleft:

3. Intrathoracic

Obstruction in this part of the airway produces an expiratory stridor.

Tracheomalacia

Tracheomalacia is a weakness in the walls of the trachea. Issues to note:

Mediastinal masses

Mediastinal masses may be caused by:

Management of stridor

All newborns with stridor need evaluation of their airway because of the risk of significant airway obstruction.

When performing the initial history and examination, bear the list of differentials in mind.

History

A review of the history should include:

Examination

When examining the infant check for:

Initial management

Initial management of stridor involves:

Further investigations

Further investigations for stridor include:

More information

References

Recommended reading