2. Introduction
Obstructive sleep apnea (OSA) is characterized by episodes of a
complete (apnea) or partial collapse (hypopnea) of the upper airway
with an associated decrease in oxygen saturation or arousal from
sleep.
3. This disturbance results in fragmented, nonrestorative sleep.
Other symptoms include loud, disruptive snoring, witnessed
apneas during sleep, and excessive daytime sleepiness
OSA has significant implications for cardiovascular health,
mental illness, quality of life, and driving safety.
4. Etiology
Pharyngeal narrowing and closure during sleep is a complex
phenomenon, and likely multiple factors play a role in the
pathogenesis
Sleep-related reduced ventilatory drive and neuromuscular
combined with anatomic risk factors are likely to play a significant
role in upper airway obstruction during sleep
5. The anatomic factors that promote pharyngeal narrowing include large
neck circumference, soft tissue, bone, or vessels.
Many of these structures can lead to increased surrounding pressure
of the upper airway resulting in pharyngeal collapsibility
and/or insufficient space to accommodate the airflow in a portion of
the upper airway during sleep.
6. In addition, the upper airway muscle tone plays a role as when it
decreases, a repetitive total or partial airway collapse results.
The most common cause of OSA in adults is obesity, male sex, and
advancing age.
The severity of OSA decreases with age when adjusting for BMI
7. Anatomic Factors
Micrognathia, retrognathia
Facial elongation
Mandibular hypoplasia
Adenoid and tonsillar hypertrophy
Inferior displacement of the hyoid
Nonanatomic Risk Factors
Central fat distribution
Obesity
Advanced age
Male gender
Supine sleeping position
Pregnancy
8. Additional Factors
Alcohol use
Smoking
Use of sedatives and hypnotics
Associated Medical Disorders
Endocrine disorders (e.g., diabetes mellitus, metabolic syndrome,
acromegaly, and hypothyroidism)
Neurological disorders (e.g., stroke, spinal cord injury, and
myasthenia gravis)
Prader Willi syndrome
Down Syndrome
Congestive heart failure
Atrial fibrillation
Obesity hypoventilation syndrome (OHS)
