Essential Features
Obstructive sleep apnea (also known as obstructive sleep apnea/hypopnea syndrome) is characterized by repetitive episodes of breathing cessation (apneas) or diminished breathing (hyponeas) resulting from complete or partial obstruction of the pharynx or upper airway during sleep. An apnea or hypopnea by definition lasts at least 10 seconds, but typically lasts 10 to 30 seconds and sometimes even longer. These disruptions in breathing are accompanied by fluctuations in blood oxygen levels, heart rate, blood pressure and other physiological parameters. Moreover apneas and hypopneas are usually terminated with an arousal - a brief awakening that last only several seconds before the individual falls back asleep without even being aware of it. The result of such repetitive respiratory events is broken up or fragmented sleep, as well as repetitive strain on one's cardiovascular system.
Typical nighttime symptoms of obstructive sleep apnea include snoring, witnessed pauses in one's breathing, choking or gasping in one's sleep, morning headaches, dry mouth and throat, increased nocturnal urination, gastroesophageal reflux, and erectile dysfunction. Some patients with obstructive sleep apnea may experience insomnia, although many do not perceive there nighttime sleep to be problematic. Daytime symptoms include excessive sleepiness, fatigue, concentration and memory difficulties and mood alternations (such as depression or irritability). Sleepiness can take the form of a need for naps during the day, or unintentional sleep episodes occurring during passive activities such as watching T.V. or reading, social activities such as at work or at a theatre, or even active activities such as in the middle of a conversation or driving.
Most patients with obstructive sleep apnea are completely unaware of the nighttime difficulties they are having, and seek clinical attention because of the sleepiness and fatigue they are experiencing during the day. Others do not even realize they have excessive daytime sleepiness, having lived with it for so long, and seek medical assistance only at the insistence of their bed partners (who often have their own sleep disrupted because of their partners loud snoring). For many patients, the full extent of their sleep apnea is only appreciated after having a sleep study, and/or receiving treatment for their condition.
Obstructive sleep apnea only one of several known sleep related breathing disorders. In particular obstuctive sleep apnea should be distinguished from central sleep apnea.
