Sleep Disorders > Types > Obstructive Sleep Apnea

Obstructive Sleep Apnea: Overview

Sleep Apnea is a condition characterized by brief interruptions of breathing during sleep. People with sleep apnea may have symptoms of: loud, frequent snoring, frequent episodes of apnea (breath holding), or daytime sleepiness.

More than 12 million Americans are estimated to have obstructive sleep apnea (OSA). Because people with sleep apnea don't usually get restful sleep at night, they may be excessively sleepy during the day, which can lead to difficulties at school and work and even to car accidents. Untreated severe OSA is associated with a higher risk for insulin resistance, heart attack, high blood pressure and stroke, and many people with these conditions have undiagnosed OSA. But once OSA is diagnosed, it can be treated-which reduces the risk of diseases that often accompany the syndrome.

Several structures of the nose, mouth, and throat can be involved in OSA. The uvula is the piece of tissue that hangs down from the soft palate, at the back of the roof of the mouth. Tonsils are on either side of the throat at the back of the mouth; they are made of lymphoid tissue, part of the body's immune system. The position of the tongue can also affect nighttime breathing. These structures can cause OSA by obstructing airflow. Because of greater work to pull in air, the airway collapses due to the strong negative pressure produced by the body's effort to breathe.


Types of Sleep Apnea

There are two types of sleep apnea: obstructive and central.

Obstructive sleep apnea (OSA) is the most common type. This is caused when the upper airways collapse during sleep and air cannot flow into or out of one's nose or mouth, although efforts to breathe continue. Breathing stops for several seconds to over a minute and levels of blood oxygen may drop during these episodes. Each episode can cause one to awaken though he or she may not realize it because they fall back asleep quickly.

Central sleep apnea (CSA) is a much less common condition and occurs when the brain does not send the appropriate signals to the breathing muscles for respiration. Since many people with central sleep apnea have other medical conditions such as congestive heart failure or stroke, treating those conditions may resolve the central sleep apnea, too.

Continuous positive airway pressure, or CPAP, may also help people with central sleep apnea. Some people with central sleep apnea may also be tried on bi-level positive pressure therapy (BPAP or BiPAP).

Supplemental oxygen may given for some patients with central sleep apnea.

Drugs occasionally given for central sleep apnea include acetazolamide. Acetazolamide is normally prescribed for epilepsy, glaucoma, and altitude sickness, but some studies have found that it decreases the apnea episodes in central sleep apnea if taken at bedtime.

Some people have both types of sleep apnea.