What is obstructive sleep apnea (OSA)?

Updated: Sep 24, 2019
  • Author: Wendy M Smith, MD; Chief Editor: Arlen D Meyers, MD, MBA  more...
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Obstructive sleep apnea (OSA) is a common, widely underdiagnosed condition that is associated with significant morbidity and mortality. Due to intermittent anatomical blockage of the upper airway, reduction or cessation of airflow occurs during sleep, resulting in recurrent oxygen desaturation and sympathetic neural activation, with resultant nighttime hypertension and cortical arousal. This cycle results in sleep fragmentation and limits the amount of time spent in deeper sleep stages. Common symptoms include snoring, restless sleep, daytime fatigue, and morning headaches.

If not treated, OSA is associated with an increased risk of cardiac, respiratory, and metabolic conditions, including hypertension, stroke, congestive heart failure, and sudden death. [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13] The estimated prevalence of OSA with associated daytime sleepiness is 4% in adult men and 2% in adult women.

The prevalence of OSA as defined by an apnea-hypopnea index (AHI) of 5 or higher is considerably higher and may include up to 24% of males and 9% of females. [14] The vast majority of these patients snore. Approximately 80–90% of patients with OSA remain undiagnosed. [15, 16]

Go to Obstructive Sleep Apnea for more complete information on this topic.

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