Snoring – the Silent Killer
An American research study showed that in a 30 to 35 year old population, 20% of men and 5% of women will snore, and by the age of 60, 60% of men and 40% of women will snore habitually. Obstructive sleep apnea is a common sleep disorder and is estimated to have an incidence of 24% in men and 9% in women. Many authorities believe that up to 93% of females and 82% of males with moderate to severe OSA remain undiagnosed. Epidemiological studies have showed that for adults over 65 years old, up to 50% have some form of sleep disruption and poor sleep quality.
In Singapore, the incidence of Obstructive Sleep Apnea is estimated to be about 15%. Obstructive Sleep Apnea falls under the category of diseases known as sleep disordered breathing (SDB).
Sleep-disordered breathing (SDB) is a spectrum of diseases related to reduced airflow through the upper airway during sleep. This is due to complete or partial upper airway obstruction or increased upper airway resistance.
Sleep disordered breathing encompass:
- simple snorers (patients who snore without excessive daytime somnolence and without any stoppages of breathing at night),
- upper airway resistance syndrome, UARS, (patients with excessive daytime somnolence but have no stoppages of breathing at night), and
- obstructive sleep apnea, OSA, (patients who snore with both excessive daytime somnolence and stoppages of breathing at night).
Snoring is frequently deemed as a social nuisance. Not a nuisance to the snorer, but a nuisance to the bed-partner. The presence of snoring is an 'alarm' that alerts one to the possibility of a sleep disorder. It is due to the vibration of the tissues in the mouth and oral cavity (namely the soft palate, uvula, base of tongue and other soft tissues).
Snoring implies an increased resistance to the inflow of air during breathing at the level of the upper airways.
Patients with adenotonsillar hypertrophy have a crowded upper airway with very little space for airflow, while obese patients frequently have a thick and fatty soft palate. It is the vibration of these soft tissues during sleep that results in snoring, when the bulk of this soft tissue exceeds a certain amount. Snoring is caused by a vibration of the structures of the oral cavity, oropharynx, soft palate, uvula, tonsils, base of tongue, epiglottis and pharyngeal walls. Occasionally, this leads to collapse, partial or complete, of these structures, which then leads to upper airway obstruction during sleep. Patients with a small jaw will also have less space available, therefore increasing the likelihood of airway compromise during sleep.
Nasal pathologies have been shown to aggravate and contribute to the severity of SDB, and treatment of the underlying nasal pathology may help, but usually not cure the disorder. There is a male predominance in OSA, this may be partly a result of hormonal differences since post-menopausal women tend to develop symptoms on average five years after menopause, with a prevalence of OSA approaching that of males. There are some reports that progesterone (female hormones) will reduce snoring and sleep apnea in males, while exogenous testosterone can increase upper airway resistance in females.
Commonest clinical symptom for patients with OSA is snoring. Most of my patients come to see me saying: "Hey doc, you know I snore; but you know what, it doesn't bother me, it bothers my wife!" This would be the social aspect behind the snoring.
Frequently, the sleep partner prompts the patient to see a physician because of concerns over repeated apneas (stoppages in breathing). Patients may complain of frequent awakenings with a choking and gasping sensation, nocturia (frequent passing urine at night), or nightmares. Many bed partners have witnessed their partners choking and holding their breaths during their sleep. Patients with severe OSA may be unable to sleep supine, as this causes the tongue to fall backwards resulting in obstruction of the airway. Common patient complaints include early morning tiredness and morning headaches (attributable to the repetitive nocturnal low oxygen levels). Morning dry mouth and throat are caused by mouth-breathing and snoring. Other symptoms include forgetfulness, depression, irritability and, less commonly, impotence.
Excessive daytime sleepiness is very common in patients with OSA, and is caused by a combination of frequent arousals, sleep fragmentation, repetitive oxygen desaturations, and reductions in delta and rapid eye movement (REM) sleep. Excessive daytime sleepiness can be measured by a simple questionnaire known as the Epworth's Sleepiness Score (ESS).
The commonest symptoms related to obstructive sleep apnea are:
During the day:
- Daytime sleepiness,
- Poor concentration
- Poor memory
- Morning headaches
- Mood changes
During the night:
- Choking sensation at night
- Gasping for air at night
- Frequent arousals
- Nocturia (frequent passing urine)
- Loud snoring
Am I Really Sleepy?
Sleepiness is a very common symptom that most of us will feel at some point in our lives. The commonest cause of sleepiness is not enough sleep! One should first be evaluating if one is getting sufficient rest. Sleepiness may also be due to poor quality sleep. Patients with sleep apnea may get enough quantity of sleep (7 to 8 hours per night), but poor quality sleep; hence, still feeling tired and sleepy the following day. Many of my patients with sleep apnea report, "Doc, I'm so sleepy that I fall asleep before my head touches the pillow."
Can sleepiness be quantified? Many authors have tried to measure sleepiness; there are objective measures and subjective measures. Subjective sleepiness is measured with a questionnaire; the Epworth Sleepiness Scale (ESS) is an internationally used questionnaire to evaluate the patient's level of sleepiness.
Each question is rated from a zero to a three.
- Zero – being no chance of falling asleep
- One – a little chance of falling asleep
- Two – good chance of falling asleep
- Three – definitely will fall asleep
A final score of zero (minimum) to 24 (maximum). In general, a score less than 10 is considered normal, any result between 11 to 14 is considered fairly sleepy, and any score above 14 is considered sleepy. A score of 20 to 24 is a dangerous patient who might fall asleep anytime, even when driving.
There are objective measures of how much one is sleepy. These tests actually evaluate how sleepy one is; one such test is called the Multiple Sleep Latency Test (MSLT). The subject is hooked up to a polygraph machine that measures muscle tone breathing patterns and brain waves. The subject is then placed in a dark, cool and quite environment and challenged to go to sleep as quickly as possible. Sleep latency is measured as the time taken for the subject to fall asleep. The test is repeated every 2 hours throughout the day. You are said to be fully alert if you are not asleep by 20 minutes. Patients will excessive sleepiness (e.g. from sleep apnea) might fall asleep within 3 minutes consistently. This Multiple Sleep Latency Test is a very accurate index of daytime sleepiness; it is far better than asking a patient if he is feeling sleepy or not. When you are pre-occupied with activity or work, you may think that you are alert even when you are actually quite sleep deprived. Activity masks sleepiness, but the tendency to sleep is there. If you were to stop work and do something monotonous, the insidious sleepiness could reveal itself instantly and without warning cause a sleep seizure.
Evaluation of Sleep Apnea Patients
Clinical evaluation is the most important step in managing a patient with snoring and/or sleep apnea. An ear, nose and throat endoscopic examination of the upper airway assessment is crucial. All patients should have weight and height recorded, body mass index (BMI) calculated, blood pressure taken, and neck circumference measured.
Patients with snoring/sleep apnea can be divided into 2 main groups:
- those with a GLOBAL problem (patients with gross obesity, thick fat in the neck), and
- those patients with a LOCAL problem (patients who are not obese but with big tonsils, a big tongue, and/or a thick redundant palate), and
- those patients who OVERLAP, they are obese and also have a local problem, like obesity or a thick neck.
The upper airway assessment is the most important step in the evaluation of the snoring patient. This would be fundamental, in assessing and deciding the modality of treatment in all snoring / sleep apnea patients.
Anatomy to be observed:
- Nose swelling – the nose is physiologically essential in breathing, any swelling within the nose needs to be corrected in order for normal breathing to be restored.
- Tonsil size – the patient's tonsils are assessed with regards to how obstructing they are. They are graded based on their size within the oral cavity.
- Tongue size – the tongue is very essential in the evaluation, as the tongue is the final "gate-keeper" to the opening of the lungs. If it is obstructing, it would have to be treated.
- Palate thickness – if the palate was too thick or redundant, it would not only cause loud snoring but may lead to obstruction of the airway and hence, sleep apnea.
Based on the patient's BMI, neck circumference, oral cavity adequacy, tonsil size, palate size / length, tongue size, upper airway assessment, and the nasal passage size, the modality of treatment is decided together with the patient.
Treatment of snoring and sleep apnea may be conservative and/or surgical (see chapter on Treatment of Snoring/Sleep Apnea).
Do I Have Sleep Apnea?
Many studies have shown that the symptoms of a patient alone are fairly useful in predicting if one has sleep apnea or not. There are strong indicators of sleep apnea. Many of my younger patients (between 30 to 40 years old) come to my clinic with severe symptoms of sleep apnea, and who are already on anti-hypertensive (high blood pressure) medication. It is not normal for a young male to have high blood pressure; an underlying cause should be sought for.
There are some strong tell tale symptoms of sleep apnea. If you snore and have excessive daytime sleepiness, you have a close to 70% chance of having sleep apnea. If you snore, have excessive daytime sleepiness and your bed-partner noticed that you stop breathing (or noticed you gasping at night), you have an 80% probability of having sleep apnea. If you snore, have excessive daytime sleepiness, your bed-partner says you stop breathing at night, and you have high blood pressure (hypertension), you have a 90% chance of having sleep apnea.
Some simple questions that you may ask yourself to see if you might have sleep apnea:
- Do you wake up in the morning tired and foggy, and unrefreshed?
- Do you have headaches in the morning?
- Are you very sleepy during the day?
- Do you fall asleep easily during the day?
- Do you have difficulty concentrating, and completing tasks at work?
- Do you feel in a daze, like you are not in your "body"?
- Have you ever arrived home in your car but couldn't remember the trip from work?
At night, while asleep:
- Do you snore loudly each night?
- Do you have frequent pauses in breathing while you sleep (do you choke or wake up choking)?
- Are you restless during sleep, tossing and turning from one side to another?
- Do you have to sleep sitting up or propped up by pillows, because you find that you are breathless sleeping flat?
- Do you have to get up to urinate (pass urine) several times during the night?
- Have you wet your bed?
- Do you have frequent nightmares?
If you answer "yes" to any 3 of these questions, there would be a strong probability that you might have sleep apnea.
How Does Sleep Apnea Kill?
Nightmare time comes in the wee hours of the morning for people with obstructive sleep apnea. But it's no dream: That's when they're at highest risk of sudden death. It has been said that "Sleep apnea is the phantom cause of heart disease and sudden death". It is well known that patients with sleep apnea have a 6 times higher risk of dying between midnight and 6am, compared to normal non-apneic patients. As these patients with snoring and sleep apnea have numerous dips in their oxygen levels while asleep, it would not be surprising that they suffer from significant stress on the heart and brain during these low oxygen events. This in turn leads to high blood pressure, lack of oxygen in the blood and hence, strokes, heart attacks and sudden death.
In general, people with sleep apnea syndrome have a higher risk of death than the normal population. The price they pay includes a potentially crippling deterioration in daily functioning, an increased risk of high blood pressure and stroke, depression, and death either in accidents or in their sleep. The family of the person with sleep apnea syndrome will also be affected, as the patient may experience irritability, mood changes, lowered sexual drive, and a reduction of intellectual ability. In addition there are major business, insurance, health, and social costs including the loss of productivity, the impact of accidents caused by a driver or worker falling asleep, and the wasted health care dollars spent on alleviating symptoms like heart disease without treating their possible underlying cause.
Overall, it is well known that patients with sleep apnea would not live as long as people without sleep apnea. Medical research has shown that patients with severe obstructive sleep apnea (patients who stop breathing more than 30 times per hour) have a mortality rate of about 3% per year, studies done over 10 years (Marti et al).