Snoring, sleep apnoea and other sleep disorders

'SIMPLE' snoring is defined as noisy breathing during sleep with no proven health sequelae. It is a common condition affecting adult males predominantly, although it is also seen (and heard) in children and women.

The cause for snoring varies and can be multi-factorial. As air escapes from the windpipe (trachea) through the voice box (larynx) it may meet resistance from several structures (eg the epiglottis, tongue base, soft palate, lining of the throat (pharynx), uvula or palatine tonsils. The vibration of these entities causes noise and this is perceived as snoring. The noise produced is usually low pitched and can be very loud.

Certain common conditions can cause an individual to start snoring temporarily or exacerbate snoring when already present. The common cold and upper respiratory tract infections, tonsillitis, deviated nasal septum, nasal polyps, allergic rhinitis and enlarged adenoids are examples. Alcohol intake and sedative drugs are also common causes.

Simple snoring when not associated with any decrease in respiratory flow may be a social nuisance which, in some instances, affects relationships in the household leading to partners being forced into using ear plugs, sleeping in different rooms or even leaving the relationship altogether.

Treatment options

Given the multifactorial nature of snoring and the age-related conditions that predispose people to it, treatment options are very much geared to minimising precipitating conditions, lifestyle modification, medication for co-morbid conditions and selective surgery. Referral to an Otolaryngologist (Ear, Nose and Throat Surgeon) is worthwhile in recalcitrant cases. A thorough history and examination including assessment of the nasal passage utilising nasendoscopes is helpful in ascertaining the likely causative factor/s.

Snoring in children is often related to enlarged adenoids and tonsils. Acute and chronic infective and inflammatory conditions amplify the noise and in more severe cases of enlargement, lead to sleep apnoea. Allergic rhinitis is a common cause in both children and adults. It is primarily treated with lifestyle modification (ie minimising exposure to aero-allergens by avoidance measures, acaricides etc), intranasal steroids, antihistamines, immunotherapy and surgery in selected cases.

Snoring in adults can be associated with weight gain and obesity. Exercise is encouraged and may help. Cessation of smoking is advisable. The posture of the individual while asleep can exacerbate snoring and is often worsened when lying on the back as opposed to the sides. Simple postural aids that discourage snorers from lying on their back may help.

Similarly, there are a variety of devices that help to adjust the position of the jaw such as the mandibular advancement device, chin-straps and tongue retainer to help pull the tongue forward preventing collapse over the airway.

Besides allergic rhinitis, other nasal conditions that affect the nasal airway should be assessed and treated. Structural (anatomical) anomalies such as deviation of nasal septum, nasal polyps and nasal valve collapse can be surgically addressed. Less invasive adjuncts such as nasal strips and nasal valve dilators have also been shown to help.

Surgery to reduce snoring is recommended if and when less invasive methods fail to help. In carefully selected patients, operations to address the soft palates floppiness, a long (vermiform) uvula, enlarged inferior turbinates, adenoids and tonsils and a bulky tongue base can help.

Obstructive sleep apnoea (OSA)

OSA is a sleep-disorder which occurs when there is no airflow (apnoea) despite respiratory effort. It is characterised by recurrent episodes of complete upper airway collapse. Reduction in airflow (as opposed to no airflow) of more than 50 per cent is called hypopnea and OSA is also referred to as OSAHS - obstructive sleep apnoea-hypopnoea syndrome. It is commoner in men and affects about a third of Singaporeans. Recent statistics in the USA and other First World countries has shown an increasing number of children and adolescents with OSA. This may be attributed to increasing levels of obesity.

Symptoms and signs

OSA is associated with snoring but is not necessarily worse if snoring is louder and conversely milder if less sonorous. Most patients complain of daytime sleepiness and impaired concentration. Witnessed attacks by the spouse or other members of the household is helpful. Video recordings are becoming commonplace in providing the ENT surgeon an idea of the presence of the problem.

Paradoxically, poor sleep quality, restlessness and frequent arousals with the need to pass urine at night can all be symptomatic of OSA. The consequences of prolonged OSA on the performance of patients during the day is also compelling. Frequent headaches, severe fatigue, memory impairment, personality and mood changes with anxiety, depression and irritability are not infrequently seen. Some patients suffer from impotence and reduced libido. Prolonged OSA, left untreated, can lead to hypertension, enlargement of the right atrium of the heart (cor pulmonale) and stroke.

Diagnosis

Referral to an ENT surgeon or sleep (respiratory) physician is recommended. As with snoring, the specialist consultation will involve a detailed history taking note of the many features that cause OSA and contribute to it. Thereafter, the patient is examined generally (body mass index (BMI) - a ratio between weight and height) and specifically for possible factors contributing to airway collapse. Nasal, oral and pharyngeal (throat) factors are assessed. The neck circumference, size of tonsils, degree of collapse of the side walls of the throat, capacity to view the back of the throat through the mouth, shape of the upper and lower jaw (among other physical features) and dentition are carefully noted. The presence of diabetes and hypertension is also an important consideration.

Sleep studies

Sleep studies are performed to establish the diagnosis and severity of OSA. There are generally two types: sleep-laboratory based (a polysomnography) and home/domiciliary sleep studies. There are pros and cons of both types of studies. Besides measuring the saturation of oxygen (pulse oximetry), a full polysomnography provides a detailed assessment of multiple parameters while the subject is asleep including electrophysiological evaluation of the heart (ECG) brain, eyes, chin, chest and leg muscle activity. It is a supervised study and provides a comprehensive report of sleep architecture.

The home sleep study is an abridged test with a focus on the pulse oximetry, reduction in airflow and level of respiratory effort. Given the portability of the domiciliary study and the non-bulky sensors, it is unsurprising that many patients elect for this form of testing. Added to this is the fact that the testing takes place in an environment that is familiar, reducing the psychological issues of sleeping in an unfamiliar environment.

OSA can be mild, moderate or severe. The distinction between the three categories is based upon a measurement of the number of episodes of apnoeas and hypopnoeas per hour. This is known as the apnoea-hypopnoea index (AHI) and is calculated from the sleep study.

Respiratory event-related arousals (RERAs) are arousal events related to increased respiratory efforts without apnoea/hypopnoea. Increased RERAs are reflective of a disturbed sleep architecture and may be part of a less severe form of sleep disordered breathing associated with upper airway resistance syndrome (UARS). A ratio of the summation of the total RERAs, apnoeas and hypopnoeas by time provides a broader index of severity known as the respiratory disturbance index (RDI).

Management

OSA can be managed initially and when mild in a medical manner with attention to weight reduction, alcohol reduction, changing of sleep position. The use of devices for tongue repositioning have some roles and can be trialed depending on the patient.

Weight reduction in severe OSA is critical and studies have shown that it is the single best determinant for reduction in the RDI. Weight gain on the other hand is the major cause for relapses especially after surgical treatment. The gold-standard for OSA treatment is continuous positive airway pressure (CPAP). This treatment is usually administered via the nose (but can be fitted as a full-face mask) and forces air through the upper airway preventing collapse while splinting open the otherwise floppy and collapsed throat.

Surgical management of OSA is aimed primarily at widening the upper airway where possible. A variety of procedures aimed at the various levels of potential obstruction and / or collapse are available. Mild OSA may benefit from surgery to the nasal turbinates and septum, tonsils and adenoids (when enlarged), while other procedures involving the soft palate and tongue base can provide some improvement although symptoms may return in the future. Bony surgery (as opposed to soft-tissue surgery) where advancement of the mandible and upper jaw (maxilla) are undertaken by specialist units have shown benefit for some patients. The caveat however is that surgical treatments should not be viewed as a cure and should be considered after trial or rejection of CPAP therapy.

This series is produced in collaboration with Singapore Medical Specialists Centre.