Dr Dennis Chua, ear, nose and throat surgeon at Mount Elizabeth Hospital, talks about sleep apnoea and how to treat it.
What is obstructive sleep apnoea
Obstructive sleep apnoea (OSA) is a common and serious sleep disorder that causes you to stop breathing during sleep. The airway repeatedly becomes blocked, limiting the amount of air that reaches your lungs.
When this happens, you may snore loudly or make choking sounds as you try to breathe. Your brain and body becomes oxygen-deprived and you may wake up. This may happen a few times a night, or in more severe cases, several hundred times a night without you noticing.
Classic symptoms of an OSA sufferer include:
- Disturbed sleep with choking
- Frequent awakenings
1 in 3 Singaporeans may have OSA
It is estimated that 1 in 3 Singaporeans have moderate to severe OSA. The lack of oxygen your body receives can have negative long-term consequences for your health. These include:
- High blood pressure (hypertension)
- Heart disease
- Diabetes mellitus
- Cognitive impairment (eg, memory loss)
- Poor performance in school
- Early onset dementia
- Motor vehicle accidents
OSA can result in drug-resistant hypertension. Patients may notice a gradual increase in the dosage of medication needed to control the hypertension.
Left untreated, OSA can lead to heart disease as well. The disturbed sleep in an OSA sufferer can lead to an increase in inflammatory markers in the blood.
These proteins are released when the body is under stress, including during disturbed sleep. They can damage the blood vessel wall leading to a build-up of atheroma (artery-blocking plaque) and calcium deposits in the coronary arteries and neck vessels. This can significantly increase the chance of a heart attack or sudden death.
In many patients with disturbed sleep, this can result in an accumulation of a protein beta-amyloid, which is normally removed from the brain during normal sleep.
Excessive levels of this protein beta-amyloid can result in Alzheimer's disease (dementia). It has been shown in several studies that OSA sufferers have a higher chance of experiencing cognitive problems such as memory impairment or difficulty concentrating.
These problems are often attributed to ageing, when in fact treating OSA may resolve them. Another consequence of untreated OSA are mood changes such as depression.
According to a study published in the Journal of Clinical Sleep Medicine in 2015, 70% of OSA patients experience symptoms of depression. In another study of 18,980 people in Europe conducted by Stanford researcher Maurice Ohayon, people with depression were found to be 5 times more likely to suffer from sleep-disordered breathing, of which OSA is the most common form. The good news is that if the OSA is treated, the depression can be reversed.
OSA in women usually presents in an atypical fashion and tends to be underdiagnosed. Female OSA sufferers may present with different symptoms than the 'classic' symptoms of snoring, disturbed sleep and excessive sleepiness during the day. Instead, women experience fatigue, insomnia, morning headaches, mood disturbances or other symptoms. However, the consequences of OSA remains the same and it must be treated urgently as well.
Obstructive sleep apnoea in children
While the typical OSA sufferer is the middle-aged male who snores, OSA can occur in children as well. OSA in children has been recognised since the 1970s and has since been well-studied.
Consequences of untreated obstructive sleep apnoea include failure to thrive, bed-wetting, attention-deficit disorder, behaviour problems, poor academic performance and cardiopulmonary disease. The most common cause of obstructive sleep apnoea in children is adenotonsillar hypertrophy (unusual growth of the adenoid tonsil).
Children who snore may develop behavioural and cognitive problems. Snoring has been associated with poor academic performance in teenagers. A report in the Pediatrics journal in 2001 showed that when OSA is treated, children can improve in cognitive problems and academic performance.
Find out if you have obstructive sleep apnoea
A thorough assessment by an ENT specialist or sleep physician is necessary to diagnose the condition, assess its severity and recommend appropriate treatment. There are several common sites of narrowing in the nasal and oral passages that can result in obstruction. A naso-endoscopy – inserting a thin tube with a camera at its end into the nose, can help to assess for the narrowest parts of the air passages. Treatment can differ depending on the cause of obstruction.
A sleep study can be done for adults to diagnose and classify the severity of obstructive sleep apnoea. This involves monitoring the patient with wires when they sleep at night.
Treating obstructive sleep apnoea
OSA is treated with a multi-pronged approach:
- Change in diet and lifestyle, including exercise
- Medication to treat conditions such as allergic rhinitis
- Oral appliances
- Use of the Continuous Positive Airway Pressure (CPAP) machine
- Surgery in selected cases where the nasal or oral passages are narrow
The patient can also adopt simple lifestyle changes, such as avoiding alcohol for 4 – 6 hours before bed, sleeping on the side rather than the back or stomach, maintaining a healthy diet, and losing weight.
Obesity is a major factor for OSA and also a major cause of relapse. This is because more fat around the neck can narrow the oral passages.
Medications are important in patients with concomitant diagnosis of allergic rhinitis. Frequently, these patients have narrowed nasal passages and mouth-breathe at night to obtain more air. They can also experience mouth dryness in the morning. Medications such as nasal steroid sprays and antihistamine tablets can help improve nasal airflow and improve OSA symptoms.
Treatment using surgery and appliances
Oral appliances may also be used to treat OSA. It works by moving parts of the mouth to enlarge the space at the back of the mouth. These are possible options in patients with mild to moderate OSA.
However, oral appliances have downsides such as excessive salivation, dental misalignment, gum irritation and even temporomandibular joint disease (pain in the muscles that move the jaw).
A CPAP machine is a very effective way of treating OSA if the patient can accept the associated discomfort. The patient has to wear a face mask in their sleep. It is attached to a machine which pumps air to help the patient overcome the obstruction in the air passages.
The biggest downside of CPAP is compliance. However, most patients find it difficult to use this daily for the full duration of sleep due to side effects such as difficulty exhaling or a feeling of claustrophobia.
Surgery is generally useful in 2 categories of patients with OSA. Those who have nasal obstruction prior to starting CPAP therapy and in patients with an obvious source of obstruction in the air passages (such as adenotonsillar hypertrophy), where the surgery can cure the condition.
In patients who require CPAP but have nasal obstruction, nasal surgery may be necessary to widen the nasal passage before using the machine. Otherwise, the patient will not be able to tolerate the CPAP and this treatment will inevitably fail.
An example of the second category of patient would be children with adenotonsillar hypertrophy, where the nasal and oral passages are narrowed by enlarged tonsils and adenoids. If the child also has symptoms of mouth breathing at night with snoring, choking and breath-holding (apnoea), the next step would be surgery to help widen the nasal and oral passages.
Thankfully there are several minimally invasive techniques available that can help to minimise pain and hasten post-operative recovery. These surgeries can usually be performed as a day surgery.