Snoring and sleep apnoea

Clinical case scenario

Kevin, a 45-year-old obese man, attends your surgery with his wife. His wife says that he has been snoring at night for many years. She often wakes him up and asks him to lie on his side, which eases the snoring. Kevin is a taxi driver, and he feels excessively sleepy and tired throughout the day. He often has to take a break from driving, as he finds it difficult to concentrate. His snoring is also causing marital discord – his wife is sleeping in a separate bedroom. He has been diagnosed recently with hypertension.

Kevin and his wife are seeking advice about his snoring, as it is affecting their personal and professional lives.

Introduction

Snoring is a rough rattling noise made on inspiration during sleep by the vibrations of anatomical structures in the pharyngeal airway (the soft palate and uvula). Apnoea is defined as an interruption of breathing for two breathing cycles (10 seconds in an adult). Hypopnoea is a decrease in airflow or reduction in tidal volume by 50% or a desaturation of 4%. The apnoea hypopnoea index (AHI) is defined as the number of apnoea and hypopnoea in 1 hour of sleep and is used to diagnose and grade the severity of sleep apnoea.

Snoring and sleep apnoea in adults

Studies have revealed that almost half of the adult population snores frequently. The incidence is 40% in males and 30% in females (Lugaresi et al., 1980). Snoring is the earliest and most consistent sign of upper airway dysfunction leading to sleep apnoea or hypopnea syndrome. The American Sleep Disorders Association (ASDA) defined snoring as ‘loud upper airways breathing, without apnoea or hypoventilation, caused by vibrations of the pharyngeal tissues’ (Thorpy, 1990). It can be classified as mild, moderate or severe on the basis of frequency, body position, and disturbance for other people (spouse, bed partner). Moreover, ASDA defined primary snoring as snoring without sleep disruption and absence of complaint of insomnia or excessive daytime sleepiness.

The airway can be considered to be formed by three segments. The first segment is formed by the nasal cavities and nasopharynx. It is made up of bone and cartilage, hence it is rigid and the airway does not collapse due to inspiratory pressure. The second segment is the oropharynx, made up of muscles and soft tissues that are mobile allowing the diameter to decrease under negative inspiratory pressure. The collapsible part of this segment is formed anteriorly by the soft palate, the uvula, tonsillar pillars and tongue base. The third (distal) segment is formed by the larynx, a cartilaginous and rigid structure which is neither deformable nor mobile under inspiratory pressure.

In adults, the patient (or their partner) usually presents with complaints of snoring or sleep disturbance. The history is a key in differentiating simple snoring from sleep apnoea. Patients with sleep apnoea normally report sleep interruption, fatigue, day-time sleepiness, inability to concentrate, decreased libido, irritability and poor performance (Norton and Dunn, 1985). The Epworth Sleepiness Scale is widely used as a subjective measure of a patient’s sleepiness. It is a quick and easy questionnaire and can be used to judge the response to treatment as well.

Long-term, patients may develop medical problems such as hypertension, pulmonary hypertension, cor pulmonale, heart failure, arrhythmias, coronary artery disease and stroke (Kato, 2009).

Since there is a direct relationship between obesity and sleep-disordered breathing, the patient’s body mass index (BMI) should be calculated. Normal BMI is 18.5–24.9 kg/m². Neck circumference should be measured, as it gives an idea of the fat in the neck. A reading over 43 cm in males and 40 cm in females is considered abnormal.

A thorough ear, nose, throat (ENT) and head-neck examination needs to be performed. This should include the nose to look for deviated septum, turbinate hypertrophy or nasal polyps; and the oral cavity to look for tonsillar enlargement, elongated uvula or shortened tonsillar pillars. Flexible nasoendoscopy (performed by ENT specialists) gives an overall assessment of the entire airway from nasal cavities down to larynx.

In suspected cases of sleep apnoea, a sleep study (polysomnography) should be requested. Although this is the gold standard, this may not be available locally. An overnight pulse oximetry is the more easily available option. It facilitates the diagnosis and grading of sleep apnoea, on the basis of the AHI index:

Mild 5–15

Other investigations may include a lateral cephalometry. This is a lateral X-ray of the skull and soft tissues. It can offer a picture of airway patency. Sleep nasoendoscopy is performed at some centres. This involves assessing the airway via an endoscope under induced sleep.

Patients with moderate or severe sleep apnoea should be referred to a sleep clinic where continuous positive airway pressure (CPAP) or bilevel positive airway pressure (BiPAP) can be offered. CPAP is the first line therapy for the majority of cases (Flemons, 2002). It maintains a patent and adequate airway, and stops episodes of apnoea and hypopnoea immediately. It has been found to have a positive impact on alertness and can significantly improve the quality of a patient’s life. Sadly, the benefit of CPAP is hindered by poor patient compliance, which can vary from 50–60%. This largely is a consequence of issues with machine usage (for instance, mask leaks, nasal congestion, and sleep disruption) (Phillips and Kryger, 2005). More advanced machines such as the BiPAP and automatic positive airway pressure variants are also being offered to correct sleep apnoea. In addition, surgery can play a role in correcting any nasal or pharyngeal source of airway obstruction.

For patients with mild sleep apnoea or simple snoring, the treatment modalities are multi-fold, but centre around lifestyle modifications. Weight reduction has a great impact. The reduction of fat in the pharynx leads to improvement in airway narrowing. A healthy diet and regular exercise is recommended for patients with high BMI. Studies have shown that a 10% weight loss is associated with a 26% reduction in AHI scores (Peppard et al., 2000). Smoking cessation and reduction of alcohol intake where relevant are also key. Alcohol causes relaxation of muscles in the neck and pharynx, worsening airway obstruction. Smoking leads to inflammation of the mucosa, adding to the airway narrowing.

Symptoms can be improved markedly by sleeping in the lateral and not supine position. Clearly, the relaxed soft tissues of the nasopharynx are less likely to fall onto the posterior pharyngeal wall in this position. The greatest obstacle in this approach is the tendency of the patient to move to a supine position once in deep sleep. Various positioning tactics or devices can be used to ensure sleeping in the lateral position. The simplest is a tennis ball in a sock that is fixed to the back of the nightwear. This makes sleeping on the back uncomfortable. However, there are many gadgets out there. Other options include wearing a back-pack; using pillows to keep the position lateral; and vibratory devices that fix on the neck and vibrate if the patient assumes a supine position. Simply elevating the head of the bed can also aid in proper positioning of the body during sleep.

Some patients with simple snoring or mild apnoea may prefer to try devices for mandibular advancement or tongue retention. These keep the pharyngeal airway patent during sleep. The dental team can be instrumental in designing these devices, which have to be tailor-made. The compliance varies significantly, with some patients benefitting and others refusing to use them due to discomfort, a foreign body sensation or excessive salivation.

Medication that causes sedation or muscle relaxation should be avoided. The most obvious example are benzodiazepine medications. On the other hand, some medical treatment can be beneficial. For instance, in cases of allergic rhinitis and sino-nasal polyposis, a nasal steroid or anti-histaminic sprays can help to maintain a patent nasal airway. The response, however, depends on the severity of the disease.

Surgical options for the treatment of simple snoring and mild-to-moderate sleep apnoea is on the rise. The aim of surgery is to safely correct the obstructing anatomy. Routine operations include septoplasty, endoscopic sinus surgery and tonsillectomy. Uvulopalatopharyngoplasty, which corrects elongated uvula and a narrow oropharynx, is showing promising results. Tongue base reduction, insertion of stiffening implants in the tonsillar pillars, and (in extreme cases) mandibular advancement, are other surgical options.

Paediatric snoring and sleep apnoea

Sleep apnoea in a child is a serious condition, as it can effect growth, development and academic performance. It is vital to diagnose and treat sleep apnoea in children at the earliest opportunity.

Children with sleep-disordered breathing may present with a variety of symptoms. It is essential to take a detailed history from the parents to differentiate simple snoring from sleep apnoea, as there can be major repercussions. Snoring is the most common symptom. Information should be gathered on how often the child snores, the presence of witnessed apnoea episodes and aggravating factors. The parents may note their child is irritable or excessively tired during the day. They may also have difficulty concentrating in school, or be disruptive at home or school.

Bed-wetting in a previously toilet-trained child could point towards sleep disruption, as it can cause increased urine production. Interrupted sleep can cause a reduction in growth hormone. This can have an impact on the growth and development of a child.

Obesity may be exacerbated by decreased physical activity caused by fatigue. It is essential to conduct an overall assessment of the child, assess growth and development and rule out obesity. Attention deficit disorders have been found to have a high association with sleep-disordered breathing.

An ENT examination is important. Mouth breathing is frequently seen in children with a nasal obstruction. The nose should be examined to look for adenoids, allergic rhinitis and sino-nasal polyps (rare in children). When looking at the oropharynx, tonsillar hypertrophy and macroglossia should be considered. A neck examination may reveal enlarged lymph nodes suggestive of chronic tonsillitis. Even a slight suspicion of sleep apnoea in a child makes investigation in the form of overnight pulse oximetry or sleep study mandatory. These tests help diagnose and assess the severity of sleep apnoea.

Sleep apnoea in children is classified as follows:

AHI 1-5: Mild

Medical treatment can play a role for paediatric patients with allergic rhinitis, polyposis or enlarged adenoids. Here, nasal steroid sprays are the mainstay of treatment. Moderate or severe cases require surgical intervention. This is usually in the form of adeno-tonsillectomy. In children with co-morbidities, it is necessary to refer to a tertiary centre, as they may require post-operative monitoring in a high dependency unit.

KEY POINTS

Sleep apnoea needs to be diagnosed and treated early to prevent negative outcomes on the health and well-being of patients