What is obstructive sleep apnea?
Obstructive sleep apnea is a disorder in which complete or partial obstruction of the airway during sleep causes loud snoring, oxyhemoglobin desaturations and frequent arousals. As a result, affected persons have unrestful sleep and excessive daytime sleepiness. Obstructive sleep apnea syndrome (OSAS) is a debilitating sleep and breathing disorder
defined as the cessation of breathing for 10 seconds or more (an apnea) at least five times per hour of sleep. People with OSA almost always snore heavily, because the same narrowing of the airway that causes snoring can also cause OSA. Snoring may actually help cause OSA as well, because the vibration of the throat tissues can cause them to swell. However, most people who snore do not go on to develop OSA.
During sleep, the body's muscles relax, which can cause excess tissue to collapse into the upper airway (back of the mouth, nose and throat) and block breathing. When breathing is interrupted by an obstruction in the airway, the body reacts by waking enough to start breathing again. These arousals may occur hundreds of times each night but do not fully awaken the patient, who remains unaware of the loud snoring, choking and gasping for air that are typically associated with obstructive sleep apnea. Obstructive sleep apnea sufferers never get "a good night's sleep" because repeated apneas and arousals deprive patients of REM and deep-stage sleep, leading to chronic daytime exhaustion and long-term cardiovascular stress.
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.
More information on sleep apnea
What is sleep apnea? - Sleep apnea is a disorder in which a person stops breathing during the night. Sleep apnea means cessation of breath characterized by repetitive episodes of upper airway obstruction.
What types of sleep apnea are there? - There are three types of sleep apnea, including obstructive sleep apnea (OSA), central sleep apnea, mixed sleep apnea.
What is obstructive sleep apnea? - Obstructive sleep apnea is a disorder in which complete or partial obstruction of the airway during sleep causes loud snoring, oxyhemoglobin desaturations and frequent arousals.
What causes obstructive sleep apnea? - Obstructive sleep apnea is caused by repetitive upper airway obstruction during sleep as a result of narrowing of the respiratory passages.
What're the symptoms of obstructive sleep apnea? - Symptoms of obstructive sleep apnea include loud snoring, Daytime sleepiness, memory changes, depression, and irritability.
What is central sleep apnea? - Central sleep apnea is a sleep breathing disorder that occurs when the brain fails to send the appropriate signals to the breathing muscles to initiate respirations.
What causes central sleep apnea? - Conditions that can cause sentral sleep apnea include bulbar poliomyelitis, encephalitis affecting the brainstem, neurodegenerative illnesses.
What're the symptoms of central sleep apnea? - Symptoms of central sleep apnea include extreme exhaustion and sleepiness during daylight hours, early morning headaches, lack of concentration, and memory loss.
What are the risk factors for sleep apnea? - There are several factors that may predispose a person towards sleep apnea, including gender, age, ethnicity, geography, obesity, immune abnormalities.
What are the complications of sleep apnea? - Sleep apnea is a potentially life-threatening condition because there are interruptions in breathing during sleep.
How is sleep apnea diagnosed? - A sleep test, called polysomnography is done to diagnose sleep apnea. Confirmation of the diagnosis requires making measurements while the person sleeps.
What's the treatment to stop sleep apnea? - Treatment for sleep apnea is determined based on the individual's specific circumstances and can include behavioral changes, physical therapy and surgery.
What surgeries are available to cure sleep apnea? - Surgeries to stop sleep apnea include uvulopalatopharyngoplasty, laser-assisted uvulopalatoplasty, tracheostomy, radiofrequency ablation.
What about the CPAP therapy for sleep apnea? - The most effective treatment for sleep apnea is nasal continuous positive airflow pressure (CPAP) therapy.