Sleep Apnea—Obstructive Sleep Apnea Syndrome

DESCRIPTION

Sleep disordered breathing (SDB) in children refers to a spectrum of disorders that occur during sleep including central apnea, hypoventilation, and obstructive hypoventilation.
The most severe manifestation of obstructive hypoventilation, obstructive sleep apnea syndrome (OSAS), is characterized by recurrent events of complete or partial upper airway obstruction that leads to abnormal ventilation and sleep continuity.
Obstructive apnea is defined as cessation of airflow measured at the nose and mouth despite respiratory effort for two or more respiratory cycles and commonly associated with gas exchange abnormality and/or arousal.
OSAS in children is associated with neurobehavioral and cognitive deficits and cardiovascular morbidity that highlights the need for prompt recognition, diagnosis, and treatment.

8–10% of children snore.
2–4% of children have OSAS, and this rate is increasing with the rising trend of obesity.
30% of children with Down syndrome have some degree of sleep apnea by the age of 3 years.

In infants, OSAS is uncommon; however, it may exist with craniofacial anomalies, neurologic disorders with low muscle tone, laryngomalacia or tracheomalacia, and gastroesophageal reflux.
Impaired arousal mechanisms can contribute to severity of OSAS.
Adenoid and tonsillar hypertrophy are commonly noted. However, normal-size tonsils do not exclude OSAS.
Obesity is an important risk factor in all age groups.
Primary snoring (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:

Although the pathophysiology of pediatric OSAS is multifactorial, the most common cause is overgrowth of the adenoid and tonsils leading to upper airway restriction during sleep.
Obesity is a major risk factor. Obesity is associated with increased soft tissue around the upper airway. In addition, obesity impacts chest wall mechanics during sleep.
Craniofacial and genetic disorders restrict the upper airway.
Neurologic disorders can reduce upper airway tone during sleep.
OSAS may present in mild, moderate, and severe forms according to the severity of gas exchange and the degree of sleep loss.
Upper airway resistance syndrome (UARS) denotes partial airway obstruction and arousals leading to sleep loss and is not associated with gas exchange abnormalities.
OSAS is distinct from central apnea (cessation of airflow that is not accompanied by respiratory effort), which indicates brain immaturity or dysfunction.
Central apnea up to 20 seconds may be a normal finding in premature or newborn infants in the first months of life.
A central apnea associated with oxygen desaturation, bradycardia, or arousal is abnormal.
Periodic breathing is a breathing pattern associated with three or more central apneas with at least 3 seconds of duration each and separated by <20 seconds. Periodic breathing may be found in the newborn. However, it should not exceed >4% of sleep time and not be associated with hypoxemia and bradycardia.

Adenoid and tonsillar hypertrophy
Cerebral palsy
Craniofacial anomalies including midfacial hypoplasia and mandibular hypoplasia
Laryngomalacia
Neurologic and neuromuscular disorders that cause hypotonia may underlie poor ventilation during sleep.
Myelomeningocele
Gastroesophageal reflux
Obesity
Metabolic and storage disorders
Allergic rhinitis, nasal septum deviation, nasal polyps
Sedatives, seizure medications, and anesthesia
History of low birth weight
Orthodontic problems (e.g., high narrow hard palate, overlapping incisors, crossbite)
Family history of OSAS
History of prematurity and multiple gestation