What is sleep apnea?

Quick Answer
A sleep disorder characterized by intermittent cessation of airflow through the upper airway.
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Causes and Symptoms

Obstructive sleep apnea (OSA) is caused by upper airway obstruction. Soft tissue in the back of the mouth collapses during sleep and temporarily obstructs airflow into the lungs. People with sleep apnea experience many periods of apnea and hypopnea. During such periods, the oxygen level in the bloodstream can decline significantly. Since these episodes happen throughout the night, the sleep pattern is interrupted, and the person will feel sleepy during the day. Symptoms of OSA may include morning headaches, fatigue, difficulty with concentration, and daytime sleepiness (somnolence). The person might doze off while watching television, reading, or, more dangerously, driving. The person may not be aware of apnea or the resultant snoring. However, a sleeping partner will frequently notice these symptoms. It should be noted, however, that snoring alone, without apnea, is very common and does not indicate sleep apnea.

Risk factors for the development of OSA include obesity, a small jaw, a deviated septum of the nose, a big tongue, or enlarged tonsils. Smokers are also at higher risk of developing sleep apnea.

If OSA is left untreated, then medical complications may occur, such as increased risks of hypertension, heart failure, strokes, and pulmonary hypertension. In pulmonary hypertension, the lungs become stiff and fail to provide normal oxygenation. Therefore, it is extremely important to recognize and treat sleep apnea.

The clinical triad of snoring, apneic episodes, and daytime somnolence suggests OSA. A diagnosis can be made by an overnight oximeter or by a formal sleep study (polysomnography). An oximeter is a noninvasive device worn over a finger that measures the oxygen level in the bloodstream. It can be worn overnight at home and is useful for detecting any drop in oxygen level caused by apneic or hypopneic episodes. A formal sleep study requires an overnight observation in a sleep center where multiple monitors record brain waves, heart rate, breathing rate, abdominal muscle movement, and oxygen level. Based on these measurements, an apnea-hypopnea index (AHI), the average number of apneic and hypopneic episodes in one hour, is reported. An AHI of 5 to 20 is considered mild sleep apnea. An AHI of 21 to 50 is moderate, and an AHI of greater than 50 is considered severe.

Treatment and Therapy

Obese individuals with OSA should lose weight, quit smoking, and avoid sedating medications and alcohol because they may impair breathing even further.

Initial OSA treatment consists of a nasal continuous positive airflow pressure (CPAP) machine. A triangular mask fits over the nose and is hooked up to a machine that pushes air under pressure into the upper airway to keep it open. A repeat sleep study using a CPAP machine can determine the level of pressure necessary to prevent apneic and hypopneic episodes. Such a device can be very effective in treating OSA. Side effects may include anxiety from using the mask, nasal congestion, nosebleeds, dry mouth, and irritation of the skin from the mask.

Some individuals require surgical treatment, especially those who cannot tolerate the use of a CPAP machine. The procedure called uvulopalatopharyngoplasty involves surgical removal of excess soft tissue including the tonsils in the back of the mouth. Laser-assisted uvulopalatoplasty, in which a laser is used to remove the soft tissue, can be performed in the office. Other surgeries can move the tongue and jaw forward in order to open up the airway in the back of the mouth. For very severe cases of sleep apnea, an opening can be made in the trachea (the windpipe in the upper neck) to bypass the obstruction in the mouth and nose.

In May 2013, the New England Journal of Medicine published the results of a study that examined the benefits of removing the tonsils and adenoids of children with obstructive sleep apena. According to the study, children who underwent surgery showed signs of improvement in their condition, including reduced sleepiness and improved quality of life. However, nearly half of the children in the study who did not have surgery improved on their own over time.

Perspective and Prospects

Accounts of what may have been sleep apnea date back to 305 to 30 BCE and involve eleven members from seven generations of the Egyptian royal family. These individuals were obese and were reported by contemporary philosophers and historians to have a tendency toward falling asleep during social and political events.

Sleep apnea has sometimes made an appearance in literature. In the late sixteenth century, symptoms of OSA are suggested in characters created by William Shakespeare for this plays Richard II and Henry IV . In Richard II, the obese Sir John Falstaff snores and sleeps much of the day, interrupted by an apneic breathing pattern. In Henry IV, King Henry IV has trouble sleeping, with periods of not breathing in his sleep. Lewis Carroll described a character with sleep apnea in his book Alice’s Adventures in Wonderland (1865). At the Mad Hatter’s tea party, the Dormouse suffers from daytime sleepiness. The other characters try to help the Dormouse by putting him into a tight teapot, which would serve as a positive pressure to assist his breathing.

The famous composer Johannes Brahms (1833–1897) was thought to have developed sleep apnea in his later years when he gained weight. He was known to his friends to snore loudly at night. He also fell asleep during a performance by another famous composer, Franz Liszt.


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Lavie, Peretz. Restless Nights: Understanding Snoring and Sleep Apnea. Translated by Anthony Berris. New Haven, Conn.: Yale University Press, 2003.

Mason, Robert J., et al., eds. Murray and Nadel’s Textbook of Respiratory Medicine. 5th ed. Philadelphia: Saunders/Elsevier, 2010.

Randerath, Winfried J., Bernd M. Sanner, and Virend K. Somers, eds. Sleep Apnea: Current Diagnosis and Treatment. New York: S. Karger, 2006.

Rock, Peter, ed. Obesity and Sleep Apnea. Philadelphia: Saunders/Elsevier, 2005.

Terris, David J., and Richard L. Goode, eds. Surgical Management of Sleep Apnea and Snoring. Boca Raton, Fla.: Taylor & Francis, 2005.

Marcus, Carole L. "A Randomized Trial of Adenotonsillectomy for Childhood Sleep Apnea." nejm.org . 23 May. 2013.

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