When we sleep, snoring is the noise caused, on inspiration but not exclusively, by the vibration of certain soft tissues, which are released. Snoring typically affects men in their fifties, but not exclusively.
How do you explain this nocturnal noise?
After a certain age, particularly in obese subjects (fatty infiltration of the tissues concerned – base of the tongue, veil of the palate), with a sometimes short neck, elsewhere affected by retrognathism (lower jaw recessed) – very well described by Dickens in the guise of Mr. Pickwick – the airway, which ensures the passage of air into the respiratory tract, is reduced in diameter.
This narrowing causes an increase in the flow velocity of the fluid (in this case, air) so that the same volume of air passes through in the same amount of time, resulting in a noise that can be heard from a distance: snoring. In the same way, a quiet river becomes noisy when it crosses a steep area (impetuous torrent).
This is the Venturi effect.
This simple ronchopathy is not serious in itself.
Its risk being, however, to ignore its main complication: the Obstructive Sleep Apnea Syndrome (O.S.A.S.) which is a pathology to be treated.
We will immediately put aside the rare central sleep apnea, whose cause is not mechanical but neurological.
It is, in fact, a disorder of the respiratory control at the cerebral level.
The sleep apnea disorder that interests us in this article is Obstructive Sleep Apnea Syndrome (O.S.A.S.), which is a potential source of severity for the patient. Obstructive Sleep Apnea Syndrome (O.S.A.S.) is a ventilatory arrest, of variable duration (10 to 30 seconds, sometimes more), repeating at least 10 times per hour. It is a direct complication of snoring.
Soft structures no longer allow the slightest air current to pass through, at least intermittently, especially in certain positions (supine position in particular, sagging the palate veil, which has become more flaccid). After a variable period of time, the air pressure rising upstream of the obstruction, the soft tissues will contract for a moment, allowing the air to flow into the upper airways.
This passage of air, accompanied by an abrupt resumption of breathing, results clinically in a micro-awakening (restless sleep) which has the effect of “shunting” the natural sleep cycle and in particular deep, recuperative sleep. The microwakefulness generates a new cycle that goes back to square one and light sleep at the beginning of the cycle, which is not recuperative.
This is why fatigue is an important semiological element in questioning, since microwakefulness occurs mainly during the deep sleep phases.
Clinical signs of the S.A.O.S.
– Snoring and sleep apnea, an isolated clinical sign and not yet a pathology;
– Fatigue on awakening (asthenia). The patient wakes up with the impression of not having slept all night, even if the night was theoretically long. Sleep has not been restorative;
– Headaches as a consequence of poor ventilation at night, leading to a progressive increase in carbon dioxide in the blood, explaining these headaches with, often, nightmares waking the patient. The shorter nights are, generally, not accompanied by headaches, the blood pressure of carbon dioxide in the blood being lower then;
– Daytime drowsiness, consequence of non-restorative sleep with irritability, decrease in intellectual performance;
– Nycturia, i.e. feeling the need to urinate several times a night;
– Libido and erectile dysfunction described;
– Respiratory insufficiency, pulmonary arterial hypertension with shortness of breath, heart failure. Only the doctor will know how to make the diagnosis and ask for the necessary tests.
Sometimes the clinical signs are more atypical, difficult to pinpoint, making the clinical diagnosis less obvious, but they must have a S.A.O.S. investigated.
The clinical signs described above, if they affect a man in his fifties who is overweight or obese, are highly suggestive of the diagnosis. The Epworth Scale, which today is more anecdotal than anything else, can still be used as a guide.
The clinical examination will look for a mechanical obstacle that causes or increases the symptoms:
– Enlarged veil,
– Voluminous tonsils,
– Cavum mass.
Confirmation will be provided by 2 key tests, which schematically record the patient’s sleep during the night, with :
– Snoring intensity,
– Duration / frequency of apneas or hypopneas,
– And gives the key element, the sleep apnea index (or even the apnea/hypopnea index if apneas are rare and there the second examination will take all its value).