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Sleep Apnea


Kingman P. Strohl

, MD, Case School of Medicine, Case Western Reserve University

Last full review/revision Sep 2020| Content last modified Sep 2022
Topic Resources

Sleep apnea is a serious disorder in which breathing repeatedly stops long enough to disrupt sleep and often temporarily decrease the amount of oxygen and increase the amount of carbon dioxide in the blood.

  • People with sleep apnea often are very sleepy during the day, snore loudly, and have episodes of gasping or choking, pauses in breathing, and sudden awakenings with a snort.

  • Although the diagnosis of sleep apnea is in part based on a doctor's evaluation of symptoms, doctors usually use polysomnography to confirm the diagnosis and determine the severity.

  • Continuous positive airway pressure, oral appliances fitted by dentists, and sometimes surgery can be used to treat sleep apnea.

There are three types of sleep apnea:

  • Obstructive sleep apnea

  • Central sleep apnea

  • Mixed obstructive and central sleep apnea

Did You Know...

  • People who have excessive daytime sleepiness and who snore should discuss these symptoms with their doctor.

Obstructive sleep apnea

Obstructive sleep apnea, the most common type of sleep apnea, is caused by repeated closure of the throat or upper airway during sleep. The upper airway includes the passageway from mouth and nostrils to throat and down to voice box, and these structures may change position as a person breathes.

This type of apnea affects about 2 to 9% of people in the United States. Obstructive sleep apnea is more common in obese people.

Obstructive sleep apnea occurs when breathing is interrupted repeatedly during sleep for periods of more than 10 seconds. People have from 5 to 30 or more episodes of interrupted breathing per hour.

Did You Know...

  • People with obstructive sleep apnea should avoid alcohol and sedating drugs, particularly before bedtime.

Obstructive sleep apnea in children

In children, enlarged tonsils or adenoids, some dental conditions (such as a large overbite), obesity, and some birth defects (such as an abnormally small lower jaw) can cause obstructive sleep apnea. Seasonal allergies that cause significant nasal congestion can worsen sleep apnea.

Almost all affected children snore. Other sleep symptoms may include restless sleep and sweating at night. Some children wet the bed. Daytime symptoms may include mouth breathing, morning headache, and problems concentrating. Learning and some behavior problems (such as hyperactivity, impulsivity, and aggression) are often common symptoms of severe obstructive sleep apnea in children. Children may also have growth delays. Excessive daytime sleepiness is less common in children than among adults with obstructive sleep apnea.

Central sleep apnea

Central sleep apnea, a much rarer type of sleep apnea, is caused by a problem with the control of breathing in the part of the brain called the brain stem. Normally, the brain stem is very sensitive to changes in the blood level of carbon dioxide (a by-product of the body's normal chemical reactions). When carbon dioxide levels are high, the brain stem signals the respiratory muscles to breathe deeper and faster to remove carbon dioxide through exhalation, and vice versa. In central sleep apnea, the brain stem is less sensitive to changes in the carbon dioxide level. As a consequence, people who have central sleep apnea breathe less deeply and more slowly than normal.

Opioids used for pain relief and a number of other drugs can cause central sleep apnea. Being at high altitude can also cause central sleep apnea. Central sleep apnea can occur in people with heart failure Heart Failure (HF) Heart failure is a disorder in which the heart is unable to keep up with the demands of the body, leading to reduced blood flow, back-up (congestion) of blood in the veins and lungs, and/or... read more Heart Failure (HF) . A brain tumor is a very rare cause. Unlike obstructive sleep apnea, central sleep apnea is not caused by obesity.

In one form of central sleep apnea, called Ondine curse, which usually occurs in newborns, people may breathe inadequately or not at all except when they are fully awake. Ondine curse can be fatal.

Mixed sleep apnea

Mixed sleep apnea, the third type, is a combination of central and obstructive factors occurring in the same episode of sleep apnea. Episodes of mixed sleep apnea most often begin as obstructive apneas and are treated like obstructive apneas.

Symptoms of Sleep Apnea

Symptoms during sleep are usually first noticed by a sleep partner, roommate, or housemate. In all types of sleep apnea, breathing may become abnormally slow and shallow, or breathing may suddenly stop (sometimes for up to 1 minute), then resume.

Obstructive sleep apnea

In obstructive sleep apnea, the most common symptom is snoring Snoring Snoring is a raspy noise produced in the nose and throat during sleep. It is quite common and becomes more common as people age. About 57% of men and 40% of women snore. However, what qualifies... read more , but most people who snore do not have sleep apnea. In obstructive sleep apnea, snoring tends to be disruptive, with episodes of gasping or choking, pauses in breathing, and sudden awakenings with a snort. The person may awaken choking and frightened.

In the morning, people are often not aware that have awoken many times during the night. Some people wake with a sore throat or a dry mouth. When obstructive sleep apnea is severe, repeated bouts of sleep-related snorts and loud snores occur at night, and sleepiness or involuntary naps occur during the day.

People may have difficulty staying asleep.

In people who live alone, daytime sleepiness may be the most noticeable symptom. Eventually, sleepiness interferes with daytime work and reduces the quality of life. For example, the person may fall asleep while watching television, while attending a meeting, or in more extreme sleepiness even while stopped at a red light when driving. Memory may be impaired, sex drive may be reduced, and interpersonal relationships suffer because the person is unable to participate actively in relationships due to sleepiness and irritability.

Did You Know...

  • Only a few people who snore have obstructive sleep apnea, but most people who have obstructive sleep apnea snore.

Central sleep apnea

In central sleep apnea, snoring is not as prominent. However, the tempo of breathing is irregular and interrupted by pauses. Cheyne-Stokes respiration (periodic breathing) is one type of central apnea. In Cheyne-Stokes respiration, breathing gradually becomes more rapid, gradually slows down, stops for a short period, then starts again. Then the cycle repeats. Each cycle lasts 30 seconds to 2 minutes.

Obesity-hypoventilation syndrome

People who are extremely obese can have obesity-hypoventilation syndrome (termed the Pickwickian syndrome) alone or in combination with obstructive sleep apnea. Excess body fat interferes with the movement of the chest, and excess body fat below the diaphragm compresses the lungs, which combine to cause shallow, less effective breathing. Excess body fat around the throat compresses the upper airway, reducing air flow. The control of breathing may be disordered, causing central sleep apnea.

Diagnosis of Sleep Apnea

  • Doctor's evaluation of the person's symptoms

  • Polysomnography

Sleep apnea is suspected on the basis of the person's symptoms. Sometimes doctors use questionnaires to help screen for symptoms, such as excessive daytime sleepiness, which may be due to obstructive sleep apnea. The diagnosis is usually confirmed and severity is best determined in a sleep laboratory by using a test called polysomnography. This evaluation can help doctors distinguish between obstructive and central sleep apnea.

In polysomnography:

Portable monitors used at home are being used more often to help diagnose sleep apnea. These monitors measure heart rate, level of oxygen in the blood, effort of breathing, position, and airflow through the nose.

Sometimes additional testing is needed to help doctors determine the cause. People with sleep apnea may be tested for complications, such as high blood pressure and atrial fibrillation. If doctors suspect central sleep apnea, testing may rarely be needed to determine the cause.

Treatment of Sleep Apnea

  • Control of risk factors

  • Continuous positive airway pressure or mouth guards or other devices fitted by a dentist

  • Possibly airway surgery or electrical stimulation of the upper airway

People should be warned of the risks of driving, operating heavy machinery, or engaging in other activities during which falling asleep would be hazardous. People who are undergoing surgery should inform their anesthesiologist that they have sleep apnea, because anesthesia can sometimes cause additional airway narrowing.

Support groups can provide information and help people with sleep apnea and their family members cope with the condition.

Obstructive sleep apnea

With treatment, the prognosis is usually excellent. Life span is not affected, and most serious complications can be prevented. Losing weight, quitting smoking, and not using alcohol excessively can help. Nasal infections and allergies should be treated. Hypothyroidism and acromegaly should be treated. Weight loss (bariatric) surgery frequently reduces sleep apnea and reverses symptoms in people who are very overweight (morbidly obese), but even people who lose a lot of weight as a result of surgery may not experience a significant decrease in sleep apnea and the associated symptoms.

Heavy snorers and people who often choke in their sleep should not consume alcohol or take sleep aids, sedating antihistamines, or other drugs that cause drowsiness. Sleeping on the side or elevating the head of the bed can help reduce snoring. Special devices strapped on the back help prevent people from sleeping on their back. The various other devices and sprays marketed to reduce snoring may help simple snoring, but they have not been shown to relieve obstructive sleep apnea. There are several surgical procedures marketed for snoring as well, but there is little proof of how well they work and how long they are effective.

People with obstructive sleep apnea, particularly those who have excessive daytime sleepiness, benefit most predictably from continuous positive airway pressure (CPAP). With CPAP, people breathe through a face or nose mask connected to a device that provides a slightly higher pressure in the airway. This increased pressure props the throat open as the person breathes in. CPAP can be given with or without humidifying the delivered air. Close follow-up by a health care practitioner is needed during the first 2 weeks of use to ensure proper mask fit and provide appropriate encouragement as the person learns to sleep with the mask. If a person has a deviated nasal septum, doctors may recommend surgery to repair the deviated septum (septoplasty) because repair may make CPAP treatment more successful.

Some people who use CPAP still have excessive daytime sleepiness. These people may benefit from taking modafinil, which is a mild stimulant used to treat daytime sleepiness in people with obstructive sleep apnea. Other drugs are also being tested for people with obstructive sleep apnea.

Removable oral appliances, fitted by dentists, can help relieve obstructive sleep apnea (and snoring) in people with mild to moderate sleep apnea. These appliances, which are worn only while sleeping, help keep the airway open. Most appliances separate the jaws and push the lower jaw forward so the tongue cannot move backward to block the throat. Others hold the tongue forward.

Upper airway stimulation is a procedure in which an implanted electrical device is used to activate one of the two 12th cranial nerves (hypoglossal nerve). This therapy can be successful in people with moderate to severe obstructive sleep apnea who are unable to tolerate CPAP therapy.

Surgery of the head or neck as a treatment for sleep apnea is useful if there are enlarged tonsils or an obvious blockage of the upper airway by another structure. In children, surgery to remove the tonsils and adenoids is the most common treatment. This type of surgery usually relieves sleep apnea, particularly if the tonsils or adenoids are enlarged. Surgery is sometimes used in people without obvious blockage if no other treatments have worked. Another common procedure is a uvulopalatopharyngoplasty, in which tissue from around the upper airways (for example, the tonsils and adenoids) is removed. It is most often helpful in people who have mild sleep apnea. Other surgical procedures are sometimes used, but they have not been studied as thoroughly.

Central sleep apnea

The underlying disorder is treated if possible. For example, drugs may be given to reduce the severity of heart failure Heart Failure (HF) Heart failure is a disorder in which the heart is unable to keep up with the demands of the body, leading to reduced blood flow, back-up (congestion) of blood in the veins and lungs, and/or... read more Heart Failure (HF) . Otherwise, there are few, well-conducted clinical trials. Oxygen delivered by nasal prongs (not under pressure) may reduce episodes of apnea in people whose levels of blood oxygen become low while sleeping. Some people with central sleep apnea may benefit from CPAP. People with central apnea of the Cheyne-Stokes type have fewer episodes of apnea and a lower severity of heart failure with this treatment but do not survive longer. Acetazolamide can help people who have central sleep apnea caused by high altitude and possibly even people at sea level. Some people benefit from surgery to implant a device that stimulates the diaphragm (a diaphragmatic/phrenic nerve stimulator) to help the person breathe.

More Information about Sleep Apnea

The following is an English-language resource that may be useful. Please note that THE MANUAL is not responsible for the content of this resource.

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