Snoring

Snoring is noisy breathing caused by vibration of the airway walls at the back of the throat(pharynx). This may occur if the walls come close together on inspiration.  During inspiration, a negative pressure is generated in the lungs and transferred to the throat.  Normally air is then drawn into the throat and lungs via the nose.  The walls of the pharynx tend to collapse if one or more of the following situations exist:

1.  the nasal airway is blocked or partially blocked

- this means that a greater negative pressure is created in the throat on inspiration, thereby dragging the pharyngeal walls inward

2.  the tonsils are very large and unhealthy

- the extra bulk makes the pharyngeal airway more prone to collapse

3. the palate is swollen

- this is a result of snoring, rather than a cause; however if snoring persists and is severe enough, it can lead to permanently thickened tissues which in turn tend to promote  snoring tendencies

4. the back of the tongue is relatively large

- this may be relative to a slightly small jaw, or due to a generally large tongue.  This narrows the airway at that level and tends to lead to collapse of the pharynx

5. the muscles of the throat are hypotonic or floppy

- this occurs after alcohol or sleeping tablets thus increasing any snoring tendency; it also occurs naturally as sleep depth increases

6. the tissues of the throat are generally bulky

- some hormonal changes can cause this; more commonly it is due to excess weight gain

If the collapse of the airway walls is severe enough the passage may become totally obstructed.  these obstructive episodes occur most commonly during the deepest sleep.  Breathing ceases altogether, causing the snoring to stop until the sleeper has woken sufficiently for the muscles of  throat to pull the pharynx open and enable breathing to resume.  The first "new" breath is usually a large gasp.  This lightening of the depth of sleep is called "arousal"; sometimes a snorer may wake right up.

 

Video

To download a video of snoring please click on the frame on the right. The picture looks down the pharynx. At 7 o'clock one can see the uvula. In the middle of the picture is the base of tongue with the epiglottis above it. During the video you can see the soft palate, epiglottis and base of tongue vibrating. The base of tongue can be seen collapsing back. When this happens completely during sleep apnoea occurs.

Habitual snoring is associated with a poor quality of sleep; most snorers fall asleep readily yet wake up tired in the morning despite having 8 hours or more hours sleep, because they have not had sufficient REM sleep to "recharge their batteries".

The obstructive breathing episodes can become quite frequent, leading to "obstructive sleep apnoea'" or OSA. OSA often leads to heart rhythm and blood pressure problems and can cause early morning headaches.  Any snorer may convert or progress to OSA especially after drinking alcohol(usually a temporary effect), or putting on weight.

 

Assessment of  Habitual Snorers

Clinical examination is directed at assessing the effectiveness of the nasal airway, and the pharyngeal airway.

If OSA is likely then a formal sleep study should be performed to measure the severity of the breathing disorder before definitive treatment is planned.  Severe OSA requires special consideration.

 

Treatment of habitual uncomplicated snoring

1.  Weight loss is important; so is reducing alcohol intake.  The former reduces the bulk of the walls of the airway; the latter avoids excessively floppy airway muscles

2.  An adequate nasal airway is required to prevent excess "drag on the walls of the throat when breathing in.  This may still not be sufficient to stop snoring, and is only occasionally enough to prevent snoring.  A nasal spray(Betnesol) may be tried first; nasal surgery(septoplasty and trimming of nasal turbinates) may be necessary to obtain sufficient or long term improvement.  Occasionally nasal splints are appropriate, if the nasal valve area is the principle source of airway obstruction

3.  If snoring persists despite (1) & (2) above, palatal surgery can tighten the tissues of the plate preventing palatal flutter and collapse at this level.  A number of methods are available from surgery(uvulopalatoplasty), laser surgery(Laser assisted Uvulopalatoplasty), and radiofrequency surgery(somnoplasty).  Palatal surgery is only appropriate if the palate is the only or principle site of airway closure during sleep.  Otherwise there is a risk of continuing to snore and the risk of side effects of surgery. 

4.  If airway collapse occurs below the palatal level, non surgical measures to prevent airway obstruction(and snoring) should be tried.  These involve the use of special devices:

i)  CPAP This is a small mask which fits over the nose and is attached to a pump which delivers a continuous flow of or air through the nose , preventing collapse of the airway by avoiding the need for indrawing of air while breathing

ii) Mandibular Splint This dental device holds the jaw forward while sleeping, pulling the tongue away from the back of the throat, thus preventing airway collapse, the same effect can be created by performing jaw surgery.