Sleep apnea

Definition:
Sleep apnea is a condition characterized by episodes of stopped breathing during sleep. See also sleep disorders.

Alternative Names:
Obstructive sleep apnea syndrome; Apnea - sleep apnea syndrome

Causes, incidence, and risk factors:
In normal conditions, the muscles of the upper part of the throat keep this passage open to allow air to flow into the lungs. These muscles usually relax during sleep, but the passage remains open enough to permit the flow of air. Some individuals have a narrower passage, and during sleep, relaxation of these muscles causes the passage to close, and air cannot get into the lungs. Loud snoring and labored breathing occur. When complete blockage of the airway occurs, air cannot reach the lungs.

For reasons that are still unclear, in deep sleep, breathing can stop for a period of time (often more than 10 seconds). These periods of lack of breathing, or apneas, are followed by sudden attempts to breathe. These attempts are accompanied by a change to a lighter stage of sleep. The result is fragmented sleep that is not restful, leading to excessive daytime drowsiness.

Older obese men seem to be at higher risk, though as many as 40% of people with obstructive sleep apnea are not obese. Nasal obstruction, a large tongue, a narrow airway and certain shapes of the palate and jaw seem also to increase the risk. A large neck or collar size is strongly associated with obstructive sleep apnea. Ingestion of alcohol or sedatives before sleep may predispose to episodes of apnea.

The classic picture of obstructive sleep apnea includes episodes of heavy snoring that begin soon after falling asleep. The snoring proceeds at a regular pace for a period of time, often becoming louder, but is then interrupted by a long silent period during which no breathing is taking place (apnea). The apnea is then interrupted by a loud snort and gasp and the snoring returns to its regular pace. This behavior recurs frequently throughout the night.

During the apneas, the oxygen level in the blood falls. Persistent low levels of oxygen (hypoxia) may cause many of the daytime symptoms. If the condition is severe enough, pulmonary hypertension may develop leading to right-sided heart failure or cor pulmonale.

Symptoms:
It is important to emphasize that often, the person who has obstructive sleep apnea does not remember the episodes of apnea during the night. The predominant symptoms are usually associated with excessive daytime sleepiness due to poor sleep during the night. Often, family members, especially spouses, witness the periods of apnea. Symptoms that may be observed include:

• Loud snoring
• Periods of not breathing (apnea)
• Awakening not rested in the morning
• Abnormal daytime sleepiness, including falling asleep at inappropriate times
• Morning headaches
• Recent weight gain
• Limited attention
• Memory loss
• Poor judgment
• Personality changes
• Lethargy

Additional symptoms that may be associated with this disease:

• Hyperactive behavior, especially in children
• High blood pressure
• Automatic behavior (performing actions by rote)
• Leg swelling (if severe)

Signs and tests:
A complete medical history taken by a health care practitioner is the most important diagnostic tool. Often, a survey that asks a series of questions about daytime sleepiness, sleep quality and bedtime habits is given.

A physical examination of the mouth, neck and throat (oropharynx) is important to detect abnormalities that may predispose.

Tests may include:

• Sleep studies
• An ECG to show arrhythmias during sleep
• An arterial blood gases to show low oxygen or elevated carbon dioxide
• Echocardiogram to evaluate the function of the heart
• Thyroid function studies

Treatment:
The goal is to keep the airway open to prevent apneas during sleep.

Weight management (or intentional weight loss) and avoiding alcohol and sedatives at bedtime may relieve sleep apnea in some individuals. If these measures are unsuccessful in stopping sleep apnea, continuous positive airway pressure (CPAP), a form of mechanical breathing assistance that involves the use of a specially-designed mask worn over the nose or nose and mouth at night, may be prescribed.

Mechanical devices inserted into the mouth at night to keep the jaw forward may be useful in mild to moderate cases.

Surgery to remove excess tissue at the back of the throat (called a uvulopalatopharyngoplasty or UPPP), to remove enlarged tonsils or adenoids (see tonsillectomy), or to create an opening in the trachea to bypass the obstructed airway during sleep (tracheostomy), may be helpful if anatomical causes are present. In some people, surgery to remove blockage of the nose or upper throat may relieve sleep apnea.

Removing enlarged tonsils or adenoids may be all that is necessary in children to cure obstructive sleep apnea.

Support Groups:
Attending a support group with others who suffer from obstructive sleep apnea or related disorders may help persons adjust to their disease and adapt to the lifestyle changes necessary to treat it.

Expectations (prognosis):
When treated correctly, obstructive sleep apnea may be controlled. However, many persons are unable or unwilling to tolerate CPAP, and the syndrome continues.

Complications:

• Hypertension
• Right-sided heart failure
• Abnormal heart rhythm (arrhythmia)
• Excessive carbon dioxide levels (hypercapnia)
• Sleep deprivation
• Stroke
• Heart disease

Calling your health care provider:
Call your health care provider if you have excessive daytime sleepiness, or if you or your family notice symptoms of obstructive sleep apnea. If you have this condition, call if symptoms do not improve with treatment or if new symptoms develop.

Decreased consciousness, extreme somnolence, hallucinations, personality changes, and persistent confusion can indicate an emergency.