Obstructive Sleep Apnea - Sleep apnea is a disorder that commonly affects more than 12 million people in the United States. It takes its name from the Greek word apnea, which means "without breath." People with sleep apnea literally stop breathing repeatedly during their sleep, often for a minute or longer and as many as hundreds of times during a single night.
Sleep apnea can be caused by either complete obstruction of the airway (obstructive apnea) or partial obstruction (obstructive hypopnea—hypopnea is slow, shallow breathing), both of which can wake one up. There are three types of sleep apnea—obstructive, central, and mixed. Of these, obstructive sleep apnea (OSA) is the most common. OSA occurs in approximately 2 percent of women and 4 percent of men over the age of 35.
What Causes OSA?
The exact cause of OSA remains unclear. The site of obstruction in most patients is the soft palate, extending to the region at the base of the tongue. There are no rigid structures, such as cartilage or bone, in this area to hold the airway open. During the day, muscles in the region keep the passage wide open. But as a person with OSA falls asleep, these muscles relax to a point where the airway collapses and becomes obstructed.
When the airway closes, breathing stops, and the sleeper awakens to open the airway. The arousal from sleep usually lasts only a few seconds, but brief arousals disrupt continuous sleep and prevent the person from reaching the deep stages of slumber, such as rapid eye movement (REM) sleep, which the body needs in order to rest and replenish its strength. Once normal breathing is restored, the person falls asleep only to repeat the cycle throughout the night.
Typically, the frequency of waking episodes is somewhere between 10 and 60. A person with severe OSA may have more than 100 waking episodes in a single night.
Signs and Symptoms
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The signs and symptoms of OSA result from disruption of the normal sleep architecture. The frequent arousals and the inability to achieve or maintain the deeper stages of sleep can lead to excessive daytime sleepiness, nonrestorative sleep, automobile accidents, personality changes, decreased memory, erectile dysfunction (impotence), and depression.
Patients rarely complain about frequent awakenings due to obstruction, but awakenings do occur. Excessive daytime sleepiness may be mild or severe, depending on the severity of the obstruction. In some cases, patients continue to experience excessive daytime sleepiness while they are being treated for obstructive sleep apnea.
Some patients suffering from OSA fall asleep in a nonstimulating environment, such as while reading in a quiet room. Others may fall asleep in a stimulating environment, such as during business meetings, eating, and even while having sex. Patients with OSA often complain of waking up feeling like they had never slept at all. They often feel worse after taking a nap than they did before napping.
The so-called drowsy driver syndrome, which a growing number of law enforcement authorities believe to be responsible for many automobile accidents, may result from OSA, which causes some drivers to fall asleep at the wheel or to suffer from lack of alertness because of sleep deprivation. Decreased alertness places a person at risk in a variety of potentially hazardous situations. It is recommended that persons with excessive daytime sleepiness not drive or operate dangerous equipment until their condition is effectively treated. Other symptoms of OSA, such as morning headaches and frequent urination during the night, may be caused by apneic events themselves.
The physical signs that suggest OSA include loud snoring, witnessed apneic episodes, and obesity. Patients with OSA often say that their only problem is that their bed partner complains about their snoring. A large number of snorers are believed to have OSA. Many times, a sleep partner will witness an apneic event.
Hypertension is prevalent in patients with OSA, although the exact relationship is unclear. It has been shown, however, that treating OSA can modestly lower blood pressure.
Not everyone who snores has sleep apnea, but if two or more of the above symptoms are present the person should consider consulting a sleep specialist. A high score on the Epworth Sleepiness Scale is also a strong indicator of possible sleep apnea.
Complications
The most obvious complication arising from OSA is diminished quality of life brought on by chronic sleep deprivation and the symptoms described above. Coronary artery disease, cerebral vascular accidents (strokes), heart attack, and congestive heart failure are being evaluated to define the exact nature of their connection to OSA.
Some linkage between OSA and coronary artery disease, heart attack, and stroke has been demonstrated, although it is still uncertain whether OSA leads to an increased risk for these conditions or if both OSA and cardiovascular problems are caused by a common problem, such as obesity.
Obstructive sleep apnea aggravates congestive heart failure by placing stress on the heart during sleep. There is a high prevalence of OSA in patients with congestive heart failure. Congestive heart failure patients also may have central sleep apnea, a condition in which the brain signals the patient to stop breathing for short periods of time.
Recent studies have indicated that there may be a link between OSA and complications following surgery. Post-surgical complications may result from disruptions in breathing caused by obstructive sleep apnea.
Source: The Sleep Channel Developed and monitored by board-certified physicians, sleepchannel provides comprehensive, trustworthy information about sleep stages and sleep-related conditions, such as insomnia, obstructive sleep apnea (OSA), and narcolepsy. sleepchannel is a medical information website of Healthcommunities.com, Inc.
