Multiple: Sleep Apnea
Multiple: Sleep Apnea
Sleep apnea is a sleep disorder in which a person's breathing stops and starts over and over in the course of their sleep time. There are three basic forms of sleep apnea: obstructive sleep apnea (OSA), in which the interruptions in breathing are caused by a physical blockage of the airway, usually loosened tissues in the back of the throat; central sleep apnea (CSA), which results from irregular signals from the part of the brain that controls breathing; and complex (or mixed) sleep apnea, which is a combination of obstructive sleep apnea and central sleep apnea. Obstructive sleep apnea is the most common type, accounting for about 90 percent of cases.
Sleep apnea is a sleep disorder characterized by interruptions in breathing in which the person misses one or more breaths over an interval of ten seconds or longer; these episodes of interrupted breathing occur repeatedly during sleep. Some people have as many as several hundred episodes of apnea during their sleep time.
In normal sleep, the muscles at the back of throat relax, but remain open far enough to allow air to pass through the airway into the lungs. In obstructive sleep apnea, the muscles in the back of the person's throat are too relaxed and allow the tongue, the tonsils, the soft palate, or the
uvula—a triangular flap of tissue at the back of the soft palate—to slip backward or downward and block the airway.
In some people, airway blockage may be the end result of certain physical features, such as an unusually narrow airway, a large neck, or a recessed chin. When the airway closes, the person typically begins to snore or gasp for breath. As the oxygen supply in the person's blood drops, the brain gives a signal that arouses the person from sleep in order to start breathing again. The person usually does not remember waking up in order to breathe; however, their sleep is not restful because of the frequent interruptions and the person feels tired or sleepy the next day.
Central sleep apnea is unusual in people who are otherwise healthy. It is most likely to occur in people with heart disease, stroke, or damage to the brain stem—the part of the brain that controls breathing. Central sleep apnea occurs when the brain fails to transmit its normal signals to the breathing muscles. The affected person may awaken feeling short of breath or have a difficult time falling or staying asleep. As with obstructive sleep apnea, central sleep apnea can result in snoring and daytime sleepiness.
Sleep apnea is a potentially severe long-term health problem. People who are not treated for sleep apnea have a 30 percent higher risk of heart attack or premature death because the drop in the oxygen level of the blood that occurs when breathing stops temporarily can eventually damage the heart. Sleep apnea also increases a person's risk of stroke and
high blood pressure. In addition, a study conducted in 2007 reported that the brains of people with obstructive sleep apnea show evidence of tissue shrinkage in the parts of the brain that store memory. These findings help to explain why sleep apnea can lead to memory loss.
Sleep apnea can endanger the well-being of others as well as the patients themselves. Daytime sleepiness is a risk factor for motor vehicle accidents; one study showed that people with sleep apnea are three times more likely to be involved in accidents than people who do not have the disorder.
Sleep apnea is a common sleep disorder in the general American population. According to the National Institutes of Health (NIH), as many as eighteen million adults suffer from sleep apnea, with as many as ten million more who have the condition but have not been diagnosed.
Several risk factors for sleep apnea have been identified:
- Age. Middle-aged adults are more likely to have sleep apnea than children or adolescents. About 4 percent of middle-aged men and 2 percent of middle-aged women in the United States have been diagnosed with sleep apnea, while about one person in ten over the age of sixty-five has the disorder.
- Sex. Men are twice as likely as women to develop sleep apnea
- Race and ethnicity. African Americans, Pacific Islanders, and Hispanics are at greater risk of sleep apnea than Caucasians, Asian Americans, or Native Americans.
- Weight. Obesity is a major risk factor in sleep apnea.
- Physical features. A large neck, narrow airway, small mouth or nose, enlarged tonsils, or a receding chin can all increase a person's risk of sleep apnea.
- Lifestyle. Drinking alcohol and smoking increase the risk of sleep apnea.
- Heredity. Sleep apnea is known to run in families, although no specific genes associated with sleep apnea have been identified as of 2008.
- Medications. Certain types of prescription drugs, particularly anti-depressants, tranquilizers, and sleeping pills, increase the risk of sleep apnea.
- Allergies. Hay fever and other allergies that cause swelling of the tissues in the nose and throat increase a person's risk of sleep apnea.
Sleep apnea has a number of possible causes ranging from congenital abnormalities in the shape of the nasal passages and airway to medical disorders or lifestyle choices that contribute to blockage of the upper airway during sleep.
In addition to daytime sleepiness, irritability, and difficulty concentrating, symptoms of sleep apnea may include:
- Loud snoring
- Waking up abruptly and feeling short of breath
- Waking with a dry mouth or sore throat
- Having a headache in the morning
- Difficulty staying asleep
- High blood pressure
- Swelling of the legs
- Poor judgment and memory loss
The diagnosis of sleep apnea is often missed, particularly in those who live alone, because people with the disorder often do not remember being aroused from sleep by the need to start breathing again. Those who share a bedroom with another family member, however, may consult their doctor when the other person complains about snoring or notices that the person with sleep apnea sometimes stops breathing completely. The doctor will take the patient's history, including a medication history, allergy history, and a family history of sleep apnea. The patient may be referred to a dentist or oral surgeon for detailed evaluation of their throat, mouth, and airway if appropriate.
The patient may also be referred to a sleep laboratory or sleep disorder center for polysomnography. A polysomnograph is a machine that measures the patient's heart, lung, and brain activity during sleep, along with their breathing patterns, arm and leg movements, and blood oxygen levels. There are also portable machines that will measure the patient's blood oxygen level, airflow, and breathing patterns during sleep. In some circumstances the doctor may allow the patient to use one of these simpler machines at home to help diagnose sleep apnea.
The treatment of sleep apnea depends partly on its cause or causes. Changes in lifestyle—particularly losing weight, quitting smoking, and cutting back on alcohol intake—may be enough to control obstructive sleep apnea in some people. According to the American Association for Respiratory Care, losing as little as 10 percent of body weight can reduce the number of times a person with obstructive sleep apnea stops breathing during sleep. If the sleep apnea is related to prescription medications, the patient's doctor may be able to adjust the dosages or substitute different drugs. Nasal sprays or allergy medications may relieve sleep apnea caused by swollen nasal tissues.
Changes in sleeping position may also help. The NIH recommends sleeping on the side rather than the back to help keep the throat open during sleep. Special pillows that prevent the person from turning onto the back are available.
Another treatment that works well for some patients with mild to moderate sleep apnea is an oral appliance fitted by a dentist for use at night. These devices are designed to keep the throat open at night by bringing the jaw forward. The dentist will check the appliance periodically to make sure that it fits correctly and that the patient's symptoms are improving.
In children or adults with enlarged tonsils, a simple tonsillectomy may cure the sleep apnea. There are also surgical procedures that can be done to correct problems in the nasal passages, such as irregularly shaped passageways or benign growths of tissue called polyps. Severe obstructive sleep apnea, however, may involve one or more of the following types of surgery:
- Surgery to remove or shrink part of the uvula or the soft palate. This type of procedure is usually done in a hospital under general anesthesia.
- Relocation or repositioning of the upper and lower jaws. This procedure is usually done by a team that includes an oral surgeon and an orthodontist. Bringing the upper and lower jaws forward enlarges the space behind the soft palate and reduces the risk of airway obstruction during sleep.
- Tracheostomy. This procedure is usually performed only when the person's sleep apnea is life-threatening and other treatments have failed. The surgeon cuts a hole in the front of the neck and inserts a metal or plastic tube to provide the patient with an artificial airway.
Patients with moderate or severe sleep apnea may benefit from continuous positive airway pressure, or CPAP. CPAP is a machine that delivers air through a mask into the patient's nose during sleep. Positive pressure means that the air delivered by the machine is under slightly greater pressure than the air in the room, and this additional pressure keeps the airway open. CPAP machines have adjustable pressure settings, and the mask can also usually be adjusted for the patient's comfort.
Patients with central sleep apnea often benefit from having the underlying medical condition treated, particularly if heart failure is involved. Supplemental oxygen therapy and CPAP are also used to treat central sleep apnea.
The prognosis of sleep apnea depends on its cause and its severity. People with mild sleep apnea usually do very well with lifestyle adjustments, allergy treatments, or changes in medications. CPAP is an effective treatment for moderate to severe sleep apnea; however, many patients find its side effects (dry nose, irritated facial skin, and headache) bothersome and stop using it. For those patients, surgery is often an effective alternative. Most patients, even those with severe sleep apnea, find that some form of treatment for this disorder can significantly improve their quality of life; it may simply take time to find the most effective treatment for a specific individual.
Sleep apnea related to a family history of the disorder or the physical characteristics of a person's throat and facial structure cannot be prevented, only corrected. Keeping one's weight at a healthful level for one's sex, age, and height, drinking only in moderation, and quitting smoking (or never starting to smoke), however, can lower an individual's risk of developing sleep apnea in middle age.
Sleep apnea is a condition that is presently attracting many researchers in the fields of psychology and neurology as well as sleep medicine. As of 2008, the National Institutes of Health was conducting 134 different
studies on sleep apnea, ranging from evaluations of surgical treatments and mouth appliances to new drugs and improvements in CPAP.
SEE ALSO Allergies; Childhood obesity; Heart failure; Obesity; Smoking; Sudden infant death syndrome
WORDS TO KNOW
Apnea : Temporary stopping of breathing.
Congenital : Present at birth.
Polysomnograph : A machine used in a sleep laboratory to monitor chest movement, air flow, brain waves, heart rhythm, and other data relevant to diagnosing sleep disorders.
Uvula : A triangular piece of soft tissue located at the back of the soft palate.
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American Academy of Family Physicians (AAFP). Sleep Apnea. Available online at http://familydoctor.org/online/famdocen/home/articles/212.html (accessed July 18, 2008).
American Association for Respiratory Care. Sleep Apnea Facts. Available online at http://www.yourlunghealth.org/lung_disease/sleep_apnea/facts/ (accessed July 18, 2008).
American Sleep Apnea Association. Information for the Patient. Available online at http://www.sleepapnea.org/info/patient.html (accessed July 18, 2008).
National Heart, Lung, and Blood Institute (NHLBI).What is Sleep Apnea? Available online at http://www.nhlbi.nih.gov/health/dci/Diseases/SleepApnea/SleepApnea_WhatIs.html (accessed July 18, 2008).
National Institute of Neurological Disorders and Stroke (NINDS). Sleep Apnea Information Page. Available online at http://www.ninds.nih.gov/disorders/sleep_apnea/sleep_apnea.htm (accessed July 18, 2008).
Sleep Apnea Specialty Centers of Michigan. Sleep Apnea Movies and Animations. Available online (links are located immediately below the box at the left of the web page) at http://www.sleepapneacenter.com/ (accessed July 18, 2008). The movie shows a patient with sleep apnea before and after using CPAP, while the animations demonstrate how the structure of the upper throat can lead to sleep apnea.