Obstructive Sleep Apnoea (OSA) is a breathing disorder that occurs during sleep
There are brief periods during which breathing stops
The causes depend on the type of sleep apnoea
4-5% of women and 8-10% of men suffer from sleep apnoea
Overweight people and those with facial deformities that could obstruct airways are more at risk
Treatment may include behavioural changes, mouth devices, CPAP treatment and surgery
What is sleep apnoea?
Sleep apnoea is a breathing disorder that occurs during sleep. It is typically accompanied by loud snoring and consists of brief periods during which breathing stops. As a result, sufferers of sleep apnoea do not get enough oxygen during sleep.
There are three types of sleep apnoea:
The first is obstructive sleep apnoea: this is the most common type and also known as The Pickwickian Syndrome. It occurs due to an obstruction in the throat during sleep.
Approximately 10 to 60 seconds pass between loud snores and the narrowing of the upper airway may be a result of several factors including inherent physical characteristics, excess weight, and alcohol consumption before going to bed.
The second is central sleep apnoea which is caused by a delay in the signal transmitted from the brain to elicit breathing. With both obstructive and central apnoea the sufferer must wake up briefly in order to breathe, sometimes hundreds of times during the night. Usually there’s no memory of these awakenings.
Thirdly, there is mixed sleep apnoea. As the name suggests, it’s more or less a mixture of the above. It usually starts as unobstructive apnoea that is then followed by upper airway obstruction. It occurs less frequently than obstructive sleep apnoea, but more frequently than central sleep apnoea.
Causes of sleep apnoea
Obstructive sleep apnoea is caused by something blocking the windpipe – the tongue, tonsils or uvula (the little piece of flesh at the very back of the throat). The most common cause is a collapse of the tongue backwards into the airway. Fatty tissue or lax throat muscles may also cause the blockage.
Central sleep apnoea involves the nervous system and is more rare. The muscles used to breathe get mixed or confused messages from the brain – or the signal might be interrupted.
Who is at risk?
Studies indicate that 4-5% of women and 8-10% of men suffer from sleep apnoea. Overweight people and those with facial deformities that could obstruct airways are more at risk.
Waking up still tired, groggy and struggling to stay awake during the day
Waking up with headaches
Waking up feeling a choking sensation
Gasping, holding your breath during sleep
Waking up sweating and excessive perspiring during sleep
Frequent stopping of breathing during sleep
High blood pressure
Overweight (sometimes), rapid weight-gain. Most people with obstructive sleep apnoea are overweight. This is because the repeat drop in blood oxygen causes the suppression of a chemical called leptin, and the increase of a chemical called ghrelin. This combination causes an increase in weight. When this happens, it is very difficult or impossible to lose weight.
Dry mouth upon awakening
Difficulty concentrating during the day
Several trips to the bathroom during the night
Insomnia, although, strictly speaking insomnia is not really a symptom - these people are falling asleep TOO MUCH, not TOO LITTLE. Memory problems frequently happen. Obstructive sleep apnoea (OSA) is the most common cause of cardiac irregularities in the absence of a valve lesion. There is a 7 times raised risk for motor vehicle accidents in these people, and legally they should not be behind the wheel of a car. The mood changes are not just depression - these people become highly irritable, and it can cause marital break-ups. The memory problems can be so severe as to mimic Alzheimer's disease.
Many people consider OSA to be the most important cause of the metabolic syndrome.
A sleep test, called polysomnography, is usually done to diagnose sleep apnoea. There are two kinds.
An overnight test involves monitoring brain waves, muscle tension, eye movement, respiration, oxygen level in the blood and audio monitoring of snoring and gasping.
In some countries home monitoring test are available. A sleep technologist hooks you up to all the electrodes and instructs you on how to record your sleep with a computerised polysomnograph that you take home and return in the morning.
An important risk factor is the size of your collar - in a man, if you snore and your collar is greater than 43cm, you probably have OSA. In a woman the figure is 40cm. If you are a snorer, that alone gives you a 50% risk of having OSA. If, in addition, you are tired despite having what appears to be adequate hours in bed, then you can confidently bet that you have it.
When the condition is mild it could usually be easily treated by behavioural changes. Losing weight and sleeping on your side is almost always recommended. Weight loss however has actually been shown to be ineffective in the treatment of OSA - in most cases the weight gain is the effect rather than the cause of the OSA. Also, if you can "cure" OSA by changing your sleeping position, then you really don’t have OSA! You are just a snorer! There are mouth devices available that help to keep the airway open and can reduce snoring in three different ways.
Some devices bring the jaw forward while others elevate the soft palate. You also get devices that retain the tongue from falling back in the airway and blocking breathing.
Moderate to severe sleep apnoea does not include behavioural changes and is usually treated with CPAP – Continuous Positive Airway Pressure. This is the mainstay of treatment. A machine blows air into your nose via a nose mask, keeping the airway open and unobstructed.
Then there is a Bi-level Positive Air Pressure (BiPAP) machine. This machine blows air at two different pressures. When the patient inhales, the pressure is higher and when exhaling, the pressure is lower. BiPAP is not for "more severe" cases - it is for people, for example with muscular dystrophy, who don’t have the strength to blow against the machine. Incidentally, using the BiPAP can increase the life expectancy of a child with muscular dystrophy by up to 5 years!
Some people have facial deformities that may be the cause of their sleep apnoea. It simply may be that their jaw is smaller than it should be or they could have a smaller opening at the back of the throat.
Others have enlarged tonsils, a large tongue or some other tissues partially blocking the airway.
Fixing a deviated septum may help to open the nasal passages. Removing the tonsils and adenoids or polyps may also help.
Other surgical treatments include removing excess tissue to clear the airway and moving the upper and lower jaw forward.
Success of treatment is measured by the reduction of respiratory disturbance to normal levels. If untreated, the personal and professional life of someone who has sleep apnoea could suffer considerably. And the risk of a heart attack or stroke rises.
Can it be cured?
If treated correctly, whether it is through behavioural changes, C-PAP treatment or surgery, a sufferer of sleep apnoea could be successfully cured of this debilitating condition and once again enjoy a quality life thanks to quality sleep.
It is impossible to prevent facial deformities and blocked airways due to tissue. Also, if the condition is central – and involves the nervous system, it is not something that can be prevented. What should and could be prevented is for the condition to continue.
When to call the doctor
When your partner starts complaining about your snoring, you keep waking up tired and groggy and it is detected that you gasp for air during sleep, you should see a doctor about you condition. If you wake up during the night with the sensation of being choked, you need to get medical advice.
Children should never snore at all. If a child snores, and there are complaints of attention problems at school, the tonsils should be examined and removed if they are obstructing the airway. This is frequently more effective than using Ritalin.
Sleep apnoea is a potentially life-threatening condition that requires immediate medical attention. The risks of undiagnosed obstructive sleep apnoea include heart attacks, strokes, impotence, irregular heartbeat, high blood pressure and heart disease. OSA gives a 23 times raised risk for heart attack - you are uninsurable if you have it.
In addition, obstructive sleep apnoea causes daytime sleepiness that can result in accidents, lost productivity and interpersonal relationship problems.
Reviewed by Dr Kevin Rosman, neurologist in sleep disorders, June 2010