Obstructive sleep apnoea
Obstructive sleep apnoea (OSA), also known as obstructive sleep apnoea-hypopnoea syndrome (OSAHS), is a condition in which the muscles of the back of your throat and your tongue relax during sleep, to the point where they collapse and block your airway. When this happens, you stop breathing.
After a period ranging from a few seconds to a minute, your brain registers that oxygen isn’t being drawn into the body through breathing. The brain then sends out signals to rouse you from sleep, forcing you to take a breath. This pattern can repeat itself many times during the night.
The severity of OSA is determined by the frequency of this cycle of stop/start breathing. People with OSA often complain of daytime sleepiness, fatigue, poor concentration, having a poor memory, and irritability. Some people may even experience mood changes, including depression. Often, the partner of the person with OSA reports having observed the most common symptoms of OSA: snoring and characteristic periods of non-breathing, followed by the choking or coughing that signals the person has roused sufficiently to start breathing again.
What causes obstructive sleep apnoea?
Obesity is a common cause of OSA. In particular, middle-aged men with a large collar size are at risk. Other factors that increase the risk include:
- alcohol consumption, especially in the evenings, as it will further relax the throat muscles;
- a small or receding chin;
- large tonsils;
- medications such as sleeping tablets;
- nasal congestion;
- a family history of OSA; and
- medical conditions, such as diabetes or an underactive thyroid.
Why is obstructive sleep apnoea important?
The excessive daytime sleepiness associated with OSA has been shown to increase the risk of accidents, in particular motor vehicle accidents. The condition also increases your risk of heart disease. High blood pressure, heart attacks, heart failure and strokes are all more common in people with OSA than in those not affected by the problem.
How is obstructive sleep apnoea diagnosed?
The diagnosis of OSA commonly involves an overnight sleep study, in which surface electrodes are taped to various sites on your body, including the face and scalp, to record sleep quality and breathing. While sleep studies have traditionally been performed in special sleep labs, there is an increasing move to less invasive testing, whereby overnight oxygen levels and nasal airflow can be recorded by a small portable device in your own home.
How is obstructive sleep apnoea treated?
Treatment depends on the severity of the condition. People who are affected only mildly will often respond sufficiently to changes in lifestyle. Such changes include losing weight, avoiding alcohol and sedatives at night, using a nasal spray if nasal congestion is a factor, and sleeping on your side rather than on your back. (You can be encouraged to sleep on your side by pinning a tennis ball in a sock to the back of your pyjama top.)
For people who are more severely affected by OSA, nasal continuous positive airway pressure (CPAP) is the most common treatment to be added to the lifestyle changes. This treatment involves wearing a close-fitting nasal mask at night. Air is pumped through the mask at low pressure to keep your upper airway open. While very effective, some people find this treatment difficult to tolerate. However, manufacturers are continually modifying the device to make it more acceptable. CPAP remains the preferred treatment for moderate to severe OSA.
The use of a mouthguard is another treatment option. Wearing a mouthguard during sleep holds the jaw in a forward position, thus keeping the airway open.
There are also surgical options available for people with resistant OSA.
The excessive daytime sleepiness that people with OSA experience can be treated with a medicine called modafanil (brand name Modavigil). However, this medicine does not replace the need for treatment of the underlying problem with CPAP, and is only prescribed by doctors to be used in conjunction with CPAP.
Last Reviewed: 14 September 2009
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