Sleep Apnea—Obstructive Sleep Apnea Syndrome



  • Sleep-disordered breathing encompasses a range of breathing disorders occurring during sleep. These conditions include primary snoring (PS), respiratory events related to arousals (RERA), and obstructive sleep apnea syndrome (OSAS).
  • Obstructive apnea is defined as the cessation of airflow at the nose and mouth despite respiratory effort, associated with some gas exchange abnormality and/or loss of regular sleep patterns.


  • 8–10% of children snore.
  • 1.3–4% of children have sleep apnea.
  • 30% of children with Down syndrome have some degree of sleep apnea by the age of 3 years.


  • OSAS may be subdivided into mild, moderate, and severe forms.
  • Many children with OSAS exhibit partial airway obstruction. This is known as obstructive hypoventilation or hypopnea and is more commonly seen in children than is complete obstruction.
  • OSAS is distinct from central apnea (cessation of airflow that is not accompanied by respiratory effort), which indicates brain immaturity or dysfunction.
  • Upper airway resistance syndrome is a respiratory disorder characterized by partial airway obstruction and arousals leading to sleep fragmentation and is not associated with gas exchange abnormalities.
  • Central apnea up to 20 seconds may be a normal finding in premature or newborn infants during the 1st month of life.
  • Periodic breathing: three or more episodes of central apnea lasting at least 3 seconds each, separated by <20 seconds. Periodic breathing may be found in the newborn; however, it should not exceed >4% of sleep time (from a sleep study) and is not associated with bradycardia or hypoxemia.

Risk Factors

  • In infants, OSAS is uncommon; however, it may exist with craniofacial anomalies, neurologic disorders associated with low muscle tone, laryngomalacia or tracheomalacia, and gastroesophageal reflux.
  • Impaired arousal mechanisms also contribute to abnormalities seen in OSAS.
  • In older children, OSAS may be associated with obesity. This form may resemble the adult type of OSAS.
  • PS or habitual snoring implies snoring that does not lead to abnormalities in gas exchange or sleep fragmentation; however, 20–50% of children with habitual snoring may have OSAS.


Several genetic disorders with associated craniofacial anomalies, hypotonia, and obesity may lead to OSAS. These include the following:

  • Pierre Robin syndrome
  • Treacher Collins syndrome
  • Down syndrome
  • Mucopolysaccharide disorders
  • Arnold-Chiari malformations
  • Prader-Willi syndrome
  • Hereditary neuromuscular disorders

Commonly Associated Conditions

  • Adenotonsillar hypertrophy
  • Craniofacial anomalies including midfacial hypoplasia and mandibular hypoplasia
  • Laryngomalacia
  • Neurologic and neuromuscular disorders that cause hypotonia may underlie poor ventilation during sleep.
  • Gastroesophageal reflux
  • Obesity
  • Metabolic disorders
  • Allergic rhinitis, nasal septum deviation, nasal polyps
  • Sedatives, seizure medications, and anesthesia

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