Sleep Apnea

Sleep apnea is a temporary interruption of breathing that happens repeatedly during sleep.

Many people think they have sleep apnea because they snore when sleeping. However, snoring is much more common than sleep apnea.

Obstructive sleep apnea is the most common type of sleep apnea. In obstructive sleep apnea, the body's effort to breathe is normal, but the passageway for air (airway) through the mouth and the throat is partially or completely obstructed during sleep, so that breathing is interrupted.

Another type of apnea is called central sleep apnea. In central sleep apnea, although the airway is open, changes in the part of the brain that controls breathing bring a temporary halt to the body's effort to breathe. Rarely, people have a combination of obstructive and central sleep apnea.

Sleep apnea can cause the level of oxygen in the blood to fall, and it interferes with sleep. Sleep apnea, especially obstructive sleep apnea, may increase the risk of high blood pressure, strokes, heart attacks, confusion, and depression, but whether sleep apnea actually causes these problems is unclear.

Causes and Symptoms

People who have an airway that is narrower than average may be more likely to develop obstructive sleep apnea. Disorders or drugs may cause or contribute to airway obstruction in obstructive sleep apnea. Overweight people have increased fat in the wall of the throat. The increased fat makes airway obstruction more likely, especially when people sleep on their back. Drinking alcohol or taking sleep aids regularly may add to airway obstruction, possibly by relaxing muscles in the throat.

Obstructive sleep apnea leads to loud snoring, grunting, and restlessness. A bed partner may notice periods of shallow breathing or periods when breathing appears to stop. To overcome the obstruction and low oxygen level, people with obstructive sleep apnea frequently move from deeper to lighter stages of sleep. As a result, they are irritable and feel poorly rested and sleepy the following day.

Central sleep apnea may result from disorders such as strokes, heart failure, and kidney failure, which can interfere with the brain's control of breathing. People with central sleep apnea experience repeated, prolonged periods of nonbreathing during sleep, often followed by periods of rapid breathing (Cheyne-Stokes breathing). This pattern occurs in cycles through the night.

Diagnosis

Doctors suspect obstructive sleep apnea in older people who feel excessively sleepy during the day. The combination of obesity, a thick neck, and high blood pressure increases the doctor's suspicion. Central sleep apnea is suspected if a pattern of nonbreathing alternating with rapid breathing is witnessed.

To confirm the diagnosis of either type of sleep apnea, the doctor needs to detect a fall in the level of oxygen in the blood during sleep. The diagnosis can be confirmed only by having the person undergo a specific type of test, called polysomnography, in a sleep laboratory.

Treatment

Mild obstructive sleep apnea is best treated by losing weight, eliminating excessive alcohol intake, and discontinuing use of sleep aids.

When these measures are not successful, obstructive sleep apnea is sometimes treated with mechanical devices. An orthodontic device can keep the lower jaw or tongue in a position that prevents obstruction of the airway. Most people, particularly those with moderate or severe sleep apnea, instead need a nighttime breathing apparatus that uses pressurized air to keep the airway open (continuous positive airway pressure [CPAP] or bi-level positive airway pressure [Bi-PAP]). Both CPAP and Bi-PAP are safe and effective but must be used indefinitely. Bi-PAP is used only in people who cannot tolerate CPAP. Some people find it difficult to sleep with a CPAP or Bi-PAP apparatus, but adjustments to the apparatus that improve comfort are sometimes possible.

People who have an underlying abnormality in their airway or who do not improve with a CPAP or Bi-PAP apparatus may be candidates for traditional or laser surgery to remove throat tissue that obstructs the airway (uvulopalatopharyngoplasty). But the long-term benefit of surgery is unproved.

Treatment of central sleep apnea involves treating the disorder causing it, but oxygen and drugs such as theophylline (which is used to treat asthma or chronic obstructive pulmonary disease—COPD), acetazolamide (a diuretic), and progesterone (a hormone used in women after menopause) may be of some benefit.

Outlook

Obstructive sleep apnea may cause daytime confusion, high blood pressure, strokes, and heart attacks. But adequate treatment of sleep apnea may prevent these conditions or control symptoms. Because treatment rarely cures the causes of central sleep apnea, the outlook for people with this type of apnea is not as good.