Very heavy snoring – obstructive sleep apnoea
Everyone snores to some extent. It comes from the upper airway at the back of the throat, called the ‘oropharynx’, which is a tube lined by various muscles, including those of the soft palate and tongue. Sleep causes these muscles to relax, so that the oropharynx sags inwards with the suction of breath when we breathe in. Normally, we sleep with mouth shut, which clamps the tongue to the roof of the mouth, thus stopping the tongue slipping back and further obstructing the throat. Sleeping with the mouth open allows the tongue to move back to further reduce the sagging airway, causing these floppy bits to vibrate loudly with each inhalation, and the result is snoring. This type of snoring is usually harmless, and often troubles others more than the snorers, who are usually quite oblivious to the fact that they’re the only individuals in the house able to sleep through the noise.
Yet snoring can be more than an annoyance. Sometimes the sagging of the oropharynx can develop into a total inward collapse of the airway, so that the sleeper becomes throttled and unable to breath – a condition called ‘obstructive sleep apnoea’ – OSA (‘apnoea’ comes from the Greek for ‘without breath’.) Needless to say, OSA can grossly disturb sleep and lead to excessive sleepiness, sleep related accidents, and quite possibly, a chronic form of hypertension (high blood pressure) unresponsive to blood pressure lowering drugs. During OSA, the sufferer is still asleep, and tries to regain breath, with ‘gagging sounds’ and great heaving of the rib cage and diaphragm. These attempts only make matters worse – trying to breath against a gag causes abnormal changes to air pressure in the lungs, and impairs the flow of blood within the chest, heart and lungs. Levels of oxygen in the blood fall, further affecting the heart, which needs plenty of oxygen in order to contract normally. After about 15 seconds or even longer in this apnoeic state, centres in the brain that control breathing alert the rest of the brain to the emergency and the individual starts to wake up. This partial wakefulness restores the muscle tone in the oropharynx, which opens up with a massive inrush of air into the lungs to produce a loud choking gasp-cum-snore, heard as the inaptly named “heroic snore”. Over the next 10 seconds or so, during milder snores or even normal breathing, the level of oxygen in the blood returns to normal and full sleep resumes. Although the whole cycle may last less than half a minute, it usually repeats itself many times. In very severe cases of OSA, several hundred such apnoeas and awakenings may occur during a single night – one a minute is not unusual.
These brief arousals are too short to be remembered and largely go unnoticed even in the worst sufferer, to the extent that this snorer often reports having slept well. It is why they are usually puzzled by their excessive sleepiness during the day, and are oblivious to the fact that their sleep has been so grossly disturbed. Not so long ago, the snoring would easily be overlooked by the unenlightened doctor, and the snorer would mistakenly be referred to a psychiatrist or neurologist in the belief that the excessive sleepiness had a psychological cause or might indicate brain disease. Nowadays, there are specialist sleep disorders clinics to assess and treat this problem, which is no laughing matter, as we shall see.
Snoring becomes commoner with ageing, with about half of both men and women over the age of 65 years noticeably snoring at night, but this is usually harmless and only a minority experience actual OSA to any serious extent. In people over the age of 50 years, full-blown OSA affects more men than women. About half of these sufferers are obese, as the weight of the fat around the throat and torso adds to the collapse of the oropharynx, especially when the person sleeps on his or her back. Sleeping on the side can help somewhat, but doesn’t prevent the condition. Often, a collar size of greater than 18 inches (45 cm) in a man of average height indicates obesity and potential problems with OSA. Having a large belly also promotes OSA, where it is not so much the fat under the waistline skin which is the problem, but the accompanying large masses of fat within the abdominal cavity which lead to these breathing difficulties. Alcohol markedly worsens all forms of snoring, especially sleep apnoea.
For leaner individuals, other factors contributing to OSA include a small lower jaw that pushes the tongue backwards, enlarged tonsils, a deformed palate, and an excess of folds in the mucous membrane that lie on either side of the oropharynx. A blocked nose due to a cold, chronic catarrh, nasal polyps (growths), or a previously broken nose (rugby players and boxers are particularly prone to this) cause people to sleep with the mouth open, leading to the effects just mentioned. Badly fitting dentures may worsen the condition as they can strain the oropharyngeal muscles in the daytime so that removal of the dentures at bedtime causes an unusual relaxation of these muscles during the night.
Very heavy snoring accompanied by excessive daytime sleepiness usually points to OSA, but a proper diagnosis can be made confidently only in a clinic specialising in sleep disorders, following measurement of breathing patterns and levels of oxygen in the blood during sleep. Unfortunately, there are still far too few sleep clinics in the UK.
OSA can cause high blood pressure (hypertension) as the rise in blood pressure that occurs during each apnoea episode can eventually extend into the waking hours as a permanent rise in blood pressure. This is more likely in those people having a form of hypertension resistant to drug treatment. The issue of whether OSA causes heart disease, apart from hypertension, is still controversial, but it must at least aggravate these disorders. However, most sufferers with OSA have normal blood pressure and heart function for their age.
What can be done? For obese people, the more sensible treatment is to lose weight, which will usually reduce OSA. However, this is easier said than done, and may take many months of dieting and exercising before sufficient fat is lost. For those people with enlarged tonsils and swollen throat tissues, or a damaged nose, corrective surgery can help. There is no really effective drug for treating OSA. Even though drugs that increase the tone of these throat muscles have had limited success, they do have some side effects. The most promising treatment to date is called ‘nasal Continuous Positive Airway Pressure’ or ‘nCPAP’ for short. It’s rather like a small vacuum cleaner working in reverse, providing air into the nose via a tube to a nose mask. Air is provided at a slightly higher than normal pressure, which puffs out the rear of the throat and allows normal nasal breathing. It simply allows one to breathe normally as in wakefulness. Throughout sleep, the patient wears this fitted nose mask, and provided that no air leaks out around it, and that the nCPAP pump is adjusted correctly, then the higher pressure of the air entering the nose will stop OSA instantly. The mouth remains closed (without assistance), to keep the tongue in place. nCPAP is easily used at home, and is quite portable for those nights away, although, the sight of someone wearing the mask is rather off-putting. Nevertheless, the method is harmless and is usually extremely effective. The improvement in alertness the next day, even after the first night on nCPAP, is usually dramatic.
A newer, less obtrusive and often very effective treatment is a type of denture plate, that pulls the lower jaw forward – thus opening up the back of the throat. It has to be individually designed and fitted by a dentist, and can be more expensive than a nCPAP device. It also allows the jaws to close, keeps the tongue in place, and in doing so permits normal breathing through the nose.
CHILDREN – persistent, very heavy snoring (i.e. OSA) can occur in children. It is usually the result of enlarged tonsils. This doesn’t necessarily cause sleepiness in the day, but can lead to more subtle behavioural and learning problems.