Normally during sleep, air moves through the throat and in and out of the lungs at a regular rhythm. In a person with sleep apnea, air movement is periodically diminished or stopped. There are two types of sleep apnea: obstructive sleep apnea and central sleep apnea. In obstructive sleep apnea, breathing is abnormal because of narrowing or closure of the throat. In central sleep apnea, breathing is abnormal because of a change in the breathing control and rhythm.
Sleep apnea is a serious condition that can affect a person's ability to safely perform normal daily activities and can affect long term health. Approximately 25 percent of adults are at risk for sleep apnea of some degree . Men are more commonly affected than women. Other risk factors include middle and older age, being overweight or obese, and having a small mouth and throat.
This topic review focuses on the most common type of sleep apnea in adults, obstructive sleep apnea (OSA).
HOW SLEEP APNEA OCCURS
The throat is surrounded by muscles that control the airway for speaking, swallowing, and breathing. During sleep, these muscles are less active, and this causes the throat to narrow (figure 1). In most people, this narrowing does not affect breathing. In others, it can cause snoring, sometimes with reduced or completely blocked airflow (figure 2). A completely blocked airway without airflow is called an obstructive apnea. Partial obstruction with diminished airflow is called a hypopnea. A person may have apnea and hypopnea during sleep.
Insufficient breathing due to apnea or hypopnea causes oxygen levels to fall and carbon dioxide to rise. Because the airway is blocked, breathing faster or harder does not help to improve oxygen levels until the airway is reopened. Typically, this requires the person to awaken to activate the upper airway muscles. Once the airway is opened, the person then takes several deep breaths to catch up on breathing. As the person awakens, he or she may move briefly, snort or snore, and take a deep breath. Less frequently, a person may awaken completely with a sensation of gasping, smothering, or choking.
If the person falls back to sleep quickly, he or she will not remember the event. Many people with sleep apnea are unaware of their abnormal breathing in sleep, and all patients underestimate how often their sleep is interrupted. Awakening from sleep causes sleep to be unrefreshing and causes fatigue and daytime sleepiness.
Causes of obstructive sleep apnea — Most patients have OSA because of a small upper airway. As the bones of the face and skull develop, some people develop a small lower face, a small mouth, and a tongue that seems too large for the mouth. These features are genetically determined, which explains why OSA tends to cluster in families. Obesity is another major factor. Tonsil enlargement can be an important cause, especially in children.
SLEEP APNEA SYMPTOMS
The main symptoms of OSA are loud snoring, fatigue, and daytime sleepiness. However, some people have no symptoms. For example, if the person does not have a bed partner, he or she may not be aware of the snoring. Fatigue and sleepiness have many causes and are often attributed to overwork and increasing age. As a result, a person may be slow to recognize that they have a problem. A bed partner or spouse often prompts the patient to seek medical care.
Other symptoms may include one or more of the following:
- Restless sleep
- Awakening with choking, gasping, or smothering
- Morning headaches, dry mouth, or sore throat
- Waking frequently to urinate
- Awakening unrested, groggy
- Memory impairment, difficulty concentrating, low energy
Risk factors — Certain factors increase the risk of sleep apnea.
- Increasing age. OSA occurs at all ages, but it is more common in middle and older age adults.
- Male sex. OSA is two times more common in men, especially in middle age.
- Obesity. The more obese a person is, the more likely they are to have OSA
- Sedation from medication or alcohol interferes with the ability to awaken from sleep and can lengthen periods of apnea (no breathing), with potentially dangerous consequences.
- Abnormality of the airway.
SLEEP APNEA COMPLICATIONS
Complications of sleep apnea can include daytime sleepiness and difficulty concentrating. The consequence of this is an increased risk of accidents and errors in daily activities. Studies have shown that people with severe OSA are more than twice as likely to be involved in a motor vehicle accident as people without these conditions. People with OSA are encouraged to discuss options for driving, working, and performing other high-risk tasks with a healthcare provider.
In addition, people with untreated OSA may have an increased risk of cardiovascular problems such as high blood pressure, heart attack, abnormal heart rhythms, or stroke . This risk may be due to changes in the heart rate and blood pressure that occur during sleep.
SLEEP APNEA DIAGNOSIS
The diagnosis of OSA is best made by a knowledgeable sleep medicine specialist who has an understanding of the individual's health issues. The diagnosis is usually based upon the person's medical history, physical examination, and testing, including:
- A complaint of snoring and ineffective sleep
- Neck size (greater than 17 inches in men or 16 inches in women) is associated with an increased risk of sleep apnea.
- A small upper airway: difficulty seeing the throat because of a tongue that is large for the mouth
- High blood pressure, especially if it is resistant to treatment
- If a bed partner has observed the patient during episodes of stopped breathing (apnea), choking, or gasping during sleep, there is a good possibility of sleep apnea.
Testing is usually performed in a sleep laboratory. A full sleep study is called a polysomnogram. The polysomnogram measures the breathing effort and airflow, blood oxygen level, heart rate and rhythm, duration of the various stages of sleep, body position, and movement of the arms/legs.
Home monitoring devices are available that can perform a sleep study. This is a reasonable alternative to conventional testing in a sleep laboratory if the clinician strongly suspects moderate or severe sleep apnea and the patient does not have other illnesses or sleep disorders that may interfere with the results.
SLEEP APNEA TREATMENT
Sleep apnea is best treated by a knowledgeable sleep medicine specialist. The goal of treatment is to maintain an open airway during sleep. Effective treatment will eliminate the symptoms of sleep disturbance; long-term health consequences are also reduced. Most treatments require nightly use. The challenge for the clinician and the patient is to select an effective therapy that is appropriate for the patient's problem and that is acceptable for long term use.
Continuous positive airway pressure (CPAP) — The most effective treatment for sleep apnea uses a mechanical device to keep the upper airway open during sleep. A CPAP (continuous positive airway pressure) (figure 3) device uses an air-tight attachment to the nose, typically a mask, connected to a tube and a blower which generates the pressure . Devices that fit comfortably into the nasal opening, rather than over the nose, are also available. CPAP should be used any time the person sleeps (day or night).
The CPAP device is usually used for the first time in the sleep lab, where a technician can adjust the pressure and select the best equipment to keep the airway open. While the treatment may seem uncomfortable, noisy, or bulky at first, most people accept the treatment after experiencing better sleep. However, difficulty with mask comfort and nasal congestion prevent up to 50 percent of people from using the treatment on a regular basis.
Continued follow up with a healthcare provider helps to ensure that the treatment is effective and comfortable. Changes in treatment may be needed if the person gains or loses weight, or if symptoms do not improve.
Adjust sleep position — Adjusting sleep position (to stay off the back) may help improve sleep quality in people who have OSA when sleeping on the back. However, this is difficult to maintain throughout the night and is rarely an adequate solution.
Weight loss — Weight loss may be helpful for obese or overweight patients. Weight loss may be accomplished with dietary changes, exercise, and/or surgical treatment. However, it can be difficult to maintain weight loss; the five-year success of non-surgical weight loss is only 5 percent, meaning that 95 percent of people regain lost weight. (See "Patient information: Weight loss treatments (Beyond the Basics)".)
Avoid alcohol and other sedatives — Alcohol can worsen sleepiness, potentially increasing the risk of accidents or injury. People with OSA are often counseled to drink little to no alcohol, even during the daytime. Similarly, people who take anti-anxiety medications or sedatives to sleep should speak with their healthcare provider about the safety of these medications.
People with OSA must notify all healthcare providers, including surgeons, about their condition and the potential risks of being sedated. People with OSA who are given anesthesia and/or pain medications require special management and close monitoring to reduce the risk of a blocked airway.
Dental devices — A dental device, called an oral appliance or mandibular advancement device, can reposition the jaw (mandible), bringing the tongue and soft palate forward as well. This may relieve obstruction in some people .
This treatment is excellent for reducing snoring, although the effect on OSA is often limited . As a result, dental devices are best used for mild cases of OSA when relief of snoring is the main goal. While dental devices are not as effective as CPAP for OSA, some patients prefer a dental device to CPAP. Side effects of dental devices are generally minor but may include changes to the bite with prolonged use.
Nasal valves — Valves that retard expiratory flow can be inserted into each nostril during sleep. This raises the air pressure in the throat and may decrease airway narrowing. The treatment is attractive for travel and camping, and for patients who are unable to tolerate CPAP. However, some patients find the treatment uncomfortable and success is limited in others . Nasal valves are best used for mild cases of OSA when relief of snoring is the main goal.
Surgical treatment — Surgery is generally reserved for patients who cannot tolerate or do not improve with non-surgical treatments such as CPAP or oral devices. Surgical procedures can reshape structures in the upper airways or surgically reposition the facial bones. Uvulopalatopharyngoplasty (UPPP) is one of the most commonly performed surgical procedures; it removes the uvula and excessive tissue in the throat, including the tonsils, if present.
However, this surgery and other surgeries of the soft palate have a poor rate of success (less than 50 percent) and have a high rate of relapse (when OSA symptoms return after surgery) . As a result, throat surgery is only recommended in a minority of patients and should be considered with caution.
Tracheostomy is a surgical procedure that creates a permanent opening in the neck. It is reserved for people with severe disease in whom less drastic measures have failed or are inappropriate. Although it is always successful in eliminating obstructive sleep apnea, tracheostomy requires significant lifestyle changes and carries some serious risks (eg, infection, bleeding, blockage).
WHERE TO GET MORE INFORMATION
Your healthcare provider is the best source of information for questions and concerns related to your medical problem.
This article will be updated as needed on our web site (www.uptodate.com/patients). Related topics for patients, as well as selected articles written for healthcare professionals, are also available. Some of the most relevant are listed below.
Patient level information — UpToDate offers two types of patient education materials.
The Basics — The Basics patient education pieces answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials.
Patient information: Sleep apnea (The Basics)
Patient information: Daytime sleepiness (The Basics)
Patient information: What is a sleep study? (The Basics)
Beyond the Basics — Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are best for patients who want in-depth information and are comfortable with some medical jargon.
Patient information: Weight loss treatments (Beyond the Basics)
Professional level information — Professional level articles are designed to keep doctors and other health professionals up-to-date on the latest medical findings. These articles are thorough, long, and complex, and they contain multiple references to the research on which they are based. Professional level articles are best for people who are comfortable with a lot of medical terminology and who want to read the same materials their doctors are reading.
Adherence with continuous positive airway pressure (CPAP)
Cardiovascular effects of obstructive sleep apnea
Central sleep apnea: Risk factors, clinical presentation, and diagnosis
Central sleep apnea: Treatment
Clinical presentation and diagnosis of obstructive sleep apnea in adults
Evaluation of suspected obstructive sleep apnea in children
Initiation of positive airway pressure therapy for obstructive sleep apnea in adults
Liabilities of sleep deprivation and sleep disorders
Management of obstructive sleep apnea in adults
Management of obstructive sleep apnea in children
Mechanisms and anatomic sites of upper airway obstruction in obstructive sleep apnea in adults
Mechanisms and predisposing factors for sleep related breathing disorders in children
Oral appliances in the treatment of obstructive sleep apnea in adults
Overview of obstructive sleep apnea in adults
Pharmacologic treatment of obstructive sleep apnea in adults
Polysomnography in obstructive sleep apnea in adults
Portable monitoring in obstructive sleep apnea in adults
Sleep related breathing disorders in adults: Definitions
Upper airway imaging in obstructive sleep apnea in adults
The following organizations also provide reliable health information.
- National Library of Medicine
- National Heart, Lung, and Blood Institute
- American Academy of Sleep Medicine
- National Sleep Foundation
- American Sleep Apnea Association