Obstructive sleep apnea

Alternative names:

sleep apnea - obstructive

Definition:

Episodes of cessation of breathing lasting 10 seconds or longer during sleep. See also sleep disorders.

Causes, incidence, and risk factors:

During sleep, relaxation of the muscles at the base of the throat cause obstruction of the airway, with extremely loud snoring and labored breathing. When complete blockage of the airway occurs, breathing stops. The obstruction to breathing prevents a person from reaching deeper stages of sleep, causing the symptoms of daytime drowsiness. Obstructive sleep apnea occurs most frequently in obese middle-aged men. Contributing factors may include use of alcohol or sedatives before sleep, anatomically narrowed airways, and massively enlarged tonsils and adenoids. Hypertension or pulmonary hypertension with enlarged right ventricle may be present. The incidence is 6 out of 100,000 people.

The classical presentation of obstructive sleep apnea in the adult is the appearance of snoring shortly after going to sleep. 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 may recur repetitively and frequently throughout the night. During the apneic periods the oxygen level in the blood falls dramatically. Persistent low levels of oxygen (hypoxia) causes the daytime symptoms. If the condition is severe enough, pulmonary hypertension develops and the patient may develop right sided heart failure (cor pulmonale) or myocarditis.