What is the pathophysiology of upper airway obstruction in childhood obstructive sleep apnea (OSA)?

Updated: Feb 13, 2019
  • Author: Mary E Cataletto, MD; Chief Editor: Denise Serebrisky, MD  more...
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Answer

The ability to maintain upper airway patency during the normal respiratory cycle is the result of a delicate equilibrium between the forces that promote airway closure and dilation. This "balance of forces" concept was initially proposed by 2 independent groups and reflects the current line of thought regarding the underlying pathophysiological mechanisms that result in the clinical spectrum of obstructive apnea.

The 4 major predisposing factors for upper airway obstruction are the following:

  • Anatomic narrowing

  • Abnormal mechanical linkage between airway dilating muscles and airway walls

  • Muscle weakness

  • Abnormal neural regulation

Obstructive apnea and hypopnea are related to upper airway obstruction. Upper airway obstruction may occur at one or more levels, including the nasopharynx (area from the nose to the hard palate), mouth, velopharynx (space behind the palate), retroglossal region (area behind the tongue), hypopharynx (region between the tongue base and larynx), and larynx.

The upper airway is a pliant tube whose sidewalls consist of muscle and other soft tissues. During wakefulness, neural input to a number of small muscle groups in the pharynx maintains muscle tone and airway patency. With sleep, an increased resistance to airflow normally accompanies muscular relaxation of these muscle groups. Although most people compensate for these changes, individuals with certain anatomic problems have repeated episodes of partial or complete upper airway obstruction when they sleep.


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