Obstructive sleep apnea
Encyclopedia
Obstructive sleep apnea or obstructive sleep apnea syndrome is the most common type of sleep apnea
and is caused by obstruction of the upper airway
. It is characterized by repetitive pauses in breathing during sleep, despite the effort to breathe, and is usually associated with a reduction in blood oxygen saturation
. These pauses in breathing, called apnea
s (literally, "without breath"), typically last 20 to 40 seconds.
The individual with OSA is rarely aware of having difficulty breathing, even upon awakening. It is recognized as a problem by others witnessing the individual during episodes or is suspected because of its effects on the body (sequelae). OSA is commonly accompanied with snoring
.
Symptoms may be present for years, even decades without identification, during which time the sufferer may become conditioned to the daytime sleepiness and fatigue associated with significant levels of sleep disturbance. Persons who sleep alone without a long-term human partner may not be told about their sleep disorder symptoms.
Since the muscle tone of the body ordinarily relaxes during sleep, and since, at the level of the throat, the human airway is composed of walls of soft tissue, which can collapse, it is easy to understand how breathing can be obstructed during sleep. Although a very minor degree of OSA is considered to be within the bounds of normal sleep, and many individuals experience episodes of OSA at some point in life, a much smaller percentage of people are afflicted with chronic, severe OSA.
Many people experience episodes of OSA for only a short period of time. This can be the result of an upper respiratory infection that causes nasal congestion, along with swelling of the throat, or tonsillitis that temporarily produces very enlarged tonsils. The Epstein-Barr virus
, for example, is known to be able to dramatically increase the size of lymphoid tissue during acute infection, and OSA is fairly common in acute cases of severe infectious mononucleosis
. Temporary spells of OSA syndrome may also occur in individuals who are under the influence of a drug (such as alcohol) that may relax their body tone excessively and interfere with normal arousal from sleep mechanisms.
(with periods of silence followed by gasps). Less common symptoms are morning headaches; insomnia; trouble concentrating; mood changes such as irritability
, anxiety
and depression
; forgetfulness; increased heart rate and/or blood pressure
; decreased sex drive; unexplained weight gain; increased urination and/or nocturia
; frequent heartburn or gastroesophageal reflux disease
; and heavy night sweats.
, with particular heaviness at the face and neck. Obesity is not always present with OSA; in fact, a significant number of adults with normal body mass indices (BMIs) have decrease in muscle tone causing airway collapse and sleep apnea. The cause of this decreased tone is not presently understood. The hallmark symptom of OSA syndrome in adults is excessive daytime sleepiness
. Typically, an adult or adolescent with severe long-standing OSA will fall asleep for very brief periods in the course of usual daytime activities if given any opportunity to sit or rest. This behavior may be quite dramatic, sometimes occurring during conversations with others at social gatherings.
The hypoxia (absence of oxygen supply) related to OSA may cause changes in the neurons of the hippocampus
and the right frontal cortex. Research using neuro-imaging revealed evidence of hippocampal atrophy in people suffering from OSA. They found that some sufferers have problems in mentally manipulating non-verbal information and in executive function.
", where growth is reduced. Poor growth occurs for two reasons: the work of breathing is intense enough that calories are burned at high rates even at rest, and the nose and throat are so obstructed that eating is both tasteless and physically uncomfortable. OSA in children, unlike adults, is often caused by obstructive tonsil
s and adenoid
s and may sometimes be cured with tonsillectomy
and adenoidectomy
.
This problem can also be caused by excessive weight in children. In this case, the symptoms are more like the symptoms adults feel: restlessness, exhaustion, etc.
Children with OSA may experience learning and memory deficits and OSA has also been linked to lowered childhood IQ scores.
, neuromuscular disorders
, or poor adherence to chemical and or speech-therapy treatments.
Individuals with decreased muscle tone, increased soft tissue around the airway, and structural features that give rise to a narrowed airway are at high risk for OSA. Men, in which the anatomy is typified by increased mass in the torso and neck, are at increased risk of developing sleep apnea, especially through middle age and later. Women suffer typically less frequently and to a lesser degree than do men, owing partially to physiology, but possibly also to differential levels of progesterone
. Prevalence in post-menopausal
women approaches that of men in the same age range. Women are at greater risk for developing OSA during pregnancy
.
OSA also appears to have a genetic component; those with a family history of it are more likely to develop it themselves. Lifestyle factors such as smoking may also increase the chances of developing OSA as the chemical irritants in smoke tend to inflame the soft tissue of the upper airway and promote fluid retention, both of which can result in narrowing of the upper airway. An individual may also experience or exacerbate OSA with the consumption of alcohol, sedatives, or any other medication that increases sleepiness as most of these drugs are also muscle relaxants.
and is the most common category of sleep-disordered breathing. It is a common condition in many parts of the world.
If studied carefully in a sleep lab by polysomnography (formal "sleep study"), it is believed by some authorities that approximately 1 in 5 American adults would have at least mild OSA. The precise prevalence of OSA among the adult population in western Europe and North America, however, has not been confidently established. In the mid-1990s it was estimated to be 3-4% of women and 6-7% of men.
Decreased muscle tone can be caused by drugs or alcohol, or it can be caused by neurological problems or other disorders. Some people have more than one of these issues. There is also a theory that long-term snoring might induce local nerve lesions in the pharynx in the same way as long-term exposure to vibration might cause nerve lesions in other parts of the body. Snoring is a vibration of the soft tissues of the upper airways, and studies have shown electrophysiological findings in the nerves and muscles of the pharynx indicating local nerve lesions.
Down Syndrome
is one such syndrome. In this chromosomal
abnormality, several features combine to make the presence of obstructive sleep apnea more likely. The specific features in Down Syndrome that predispose to obstructive sleep apnea include: relatively low muscle tone, narrow nasopharynx
, and large tongue. Obesity and enlarged tonsils and adenoids, conditions that occur commonly in the western population, are much more likely to be obstructive in a person with these features than without them. Obstructive sleep apnea does occur even more frequently in people with Down Syndrome than in the general population. A little over 50% of all people with Down Syndrome suffer from obstructive sleep apnea (de Miguel-Díez, et al. 2003), and some physicians advocate routine testing of this group (Shott, et al. 2006).
In other craniofacial syndromes, the abnormal feature may actually improve the airway, but its correction may put the person at risk for obstructive sleep apnea after surgery, when it is modified. Cleft palate syndromes are such an example. During the newborn period, all humans are obligate nasal breathers
. The palate is both the roof of the mouth and the floor of the nose. Having an open palate may make feeding difficult, but generally does not interfere with breathing, in fact - if the nose is very obstructed an open palate may relieve breathing. There are a number of clefting syndromes in which the open palate is not the only abnormal feature, additionally there is a narrow nasal passage - which may not be obvious. In such individuals, closure of the cleft palate- whether by surgery or by a temporary oral appliance, can cause the onset of obstruction.
Skeletal advancement in an effort to physically increase the pharyngeal
airspace is often an option for craniofacial patients with upper airway obstruction and small lower jaws (mandibles). These syndromes include Treacher Collins Syndrome
and Pierre Robin Sequence. Mandibular advancement surgery is often just one of the modifications needed to improve the airway, others may include reduction of the tongue, tonsillectomy
or modified uvulopalatoplasty
.
, compared to other procedures for treatment of velopharyngeal inadequacy
(VPI). In OSA, recurrent interruptions of respiration
during sleep are associated with temporary airway obstruction
. Following pharyngeal flap surgery, depending on size and position, the flap itself may have an "obturator
" or obstructive effect within the pharynx
during sleep, blocking ports of airflow and hindering effective respiration
. There have been documented instances of severe airway obstruction, and reports of post-operative OSA continue to increase as healthcare professionals (i.e. physicians, speech language pathologists
) become more educated about this possible dangerous condition. Subsequently, in clinical practice, concerns of OSA have matched or exceeded interest in speech outcomes following pharyngeal flap surgery.
The surgical treatment for velopalatal insufficiency may cause obstructive sleep apnea syndrome. When velopalatal insufficiency is present, air leaks into the nasopharynx even when the soft palate should close off the nose. A simple test for this condition can be made by placing a tiny mirror at the nose, and asking the subject to say "P". This p sound, a plosive, is normally produced with the nasal airway closed off - all air comes out of the pursed lips, none from the nose. If it is impossible to say the sound without fogging a nasal mirror, there is an air leak - reasonable evidence of poor palatal closure. Speech is often unclear due to inability to pronounce certain sounds. One of the surgical treatments for velopalatal insufficiency involves tailoring the tissue from the back of the throat and using it to purposefully cause partial obstruction of the opening of the nasopharynx
. This may actually cause OSA syndrome in susceptible individuals, particularly in the days following surgery, when swelling occurs (see below: Special Situation: Anesthesia and Surgery).
to complete collapse. In the cases where airflow is reduced to a degree where blood oxygen levels fall, or the physical exertion to breathe is too great, neurological mechanisms trigger a sudden interruption of sleep, called a neurological arousal. These arousals rarely result in complete awakening, but can have a significant negative effect on the restorative quality of sleep. In significant cases of OSA, one consequence is sleep deprivation
due to the repetitive disruption and recovery of sleep activity. This sleep interruption in stage 3 (also called slow-wave sleep
), and in REM sleep, can interfere with normal growth patterns, healing
, and immune response, especially in children and young adults.
These tests range, in decreasing order of cost, complexity and tethering of the patient (number and type of channels of data recorded), from lab-attended full polysomnography ("sleep study") down to single-channel home recording. In the USA, these categories are associated with insurance classification from Type I down to Type IV. Reimbursement rules vary among European countries.
Polysomnography
in diagnosing OSA characterizes the pauses in breathing. As in central apnea, pauses are followed by a relative decrease in blood oxygen and an increase in the blood carbon dioxide. Whereas in central sleep apnea the body's motions of breathing stop, in OSA the chest not only continues to make the movements of inhalation, butt the movements typically become even more pronounced. Monitors for airflow at the nose and mouth demosntrate that efforts to breathe are not only present, but that they are often exaggerated. The chest muscles and diaphragm
contract and the entire body may thrash and struggle.
An "event" can be either an apnea, characterised by complete cessation of airflow for at least 10 seconds, or a hypopnea in which airflow decreases by 50 percent for 10 seconds or decreases by 30 percent if there is an associated decrease in the oxygen saturation or an arousal from sleep . To grade the severity of sleep apnea, the number of events per hour is reported as the apnea-hypopnea index
(AHI). An AHI of less than 5 is considered normal. An AHI of 5-15 is mild; 15-30 is moderate and more than 30 events per hour characterizes severe sleep apnea.
found that home oximetry (a non-invasive method of monitoring blood oxygenation) may be adequate and easier to obtain than formal polysomnography. High probability patients were identified by an Epworth Sleepiness Scale
(ESS) score of 10 or greater and a Sleep Apnea Clinical Score (SACS) of 15 or greater. Home oximetry, however, does not measure apneic events or respiratory event-related arousals and thus does not produce an AHI value.
In acute infectious mononucleosis
, for example, although the airway may be severely obstructed in the first 2 weeks of the illness, the presence of lymphoid tissue (suddenly enlarged tonsils and adenoids) blocking the throat is usually only temporary. A course of anti-inflammatory steroids such as prednisone
(or another kind of glucocorticoid drug) is often given to reduce this lymphoid tissue. Although the effects of the steroids are short term, in most affected individuals, the tonsillar and adenoidal enlargement are also short term, and will be reduced on its own by the time a brief course of steroids is completed. In unusual cases where the enlarged lymphoid tissue persists after resolution of the acute stage of the Epstein-Barr infection, or in which medical treatment with anti-inflammatory steroids does not adequately relieve breathing, tonsillectomy and adenoidectomy
may be urgently required.
OSA in children is sometimes due to chronically enlarged tonsils and adenoids. Tonsillectomy and adenoidectomy is curative. The operation may be far from trivial, especially in the worst apnea cases, in which growth is retarded and abnormalities of the right heart may have developed. Even in these extreme cases, the surgery tends to cure not only the apnea and upper airway obstruction, but allows normal subsequent growth and development. Once the high end-expiratory pressures are relieved, the cardiovascular complications reverse themselves. The postoperative period in these children requires special precautions (see "Surgery and obstructive sleep apnea syndrome" below).
The treatment of OSA in adults with poor oropharyngeal
airways secondary to heavy upper body type is varied. Unfortunately, in this most common type of OSA, unlike some of the cases discussed above, reliable cures are not the rule.
Some treatments involve lifestyle changes, such as avoiding alcohol and medications that relax the central nervous system (for example, sedatives and muscle relaxants), losing weight, and quitting smoking. Some people are helped by special pillows or devices that keep them from sleeping on their backs, or oral appliances to keep the airway open during sleep. For those cases where these conservative methods are inadequate, doctors can recommend continuous positive airway pressure
(CPAP), in which a face mask is attached to a tube and a machine that blows pressurized air into the mask and through the airway to keep it open. There are also surgical procedures intended to remove and tighten tissue and widen the airway, but none has been reproducibly successful. Some individuals may need a combination of therapies to successfully treat their condition.
inflates it. There are several variants:
A second type of physical intervention, a Mandibular advancement splint
(MAS), is sometimes prescribed for mild or moderate sleep apnea sufferers. The device is a mouthguard similar to those used in sports to protect the teeth. For apnea patients, it is designed to hold the lower jaw slightly down and forward relative to the natural, relaxed position. This position holds the tongue farther away from the back of the airway, and may be enough to relieve apnea or improve breathing for some patients.
The FDA accepts only 16 oral appliances for the treatment of sleep apnea. A listing is available at its website.
Oral appliance therapy is less effective than CPAP, but is more 'user friendly'. Side-effects are common, but rarely is the patient aware of them.
, has shown early promise at the University of Illinois at Chicago
. This small, early study found a 50% decrease in occurrence of apnea episodes and 28% decrease in sleep disruptions in 100% of patients (twelve patients) taking them. Nonetheless, due to the risk of weight gain and sedation (two risk factors and consequences of sleep apnea) it is not recommended. An effort to improve the effects of mirtazapine by combining it with another existing medication was cancelled during Phase IIa trials in 2006. Dr. David Carley and Dr. Miodrag Radulovacki, the sleep researchers who were behind the initial clinical trial of mirtazapine are now working on a new treatment that consists of two other existing medications taken off-label together for treatment of sleep apnea.
Other serotonin effecting agents that have been explored unsuccessfully as a treatment for apnea include fluoxetine
, tryptophan
and protriptyline
.
Oral administration of the methylxanthine theophylline
(chemically similar to caffeine
) can reduce the number of episodes of apnea, but can also produce side effects such as heart palpitations and insomnia
. Theophylline is generally ineffective in adults with OSA, but is sometimes used to treat central sleep apnea (see below), and infant
s and children with apnea.
When other treatments do not completely treat the OSA, drugs are sometimes prescribed to treat a patient's daytime sleepiness or somnolence
. These range from stimulants such as amphetamine
s to modern anti-narcoleptic
medicines. The anti-narcoleptic
medicine modafinil
is seeing increased use in this role .
In most cases, weight loss will reduce the number and severity of apnea episodes. In the morbidly obese, a major loss of weight (such as what occurs after bariatric surgery
) can sometimes cure the condition.
This is not a common mode of treatment for OSA patients as of 2004, but it is an active field of research.
The role of surgery in the treatment of sleep apnea has been questioned repeatedly as the long term success rate of the procedures has come into question. Patient selection in the past was oftentimes quite poor, resulting in poor overall results. Potential surgical candidates should now be extensively examined to assure the site of obstruction is clearly evident prior to any surgical intervention.The patient's age, weight and other factors may make them a bad candidate for surgery. When a patient can tolerate it, positive air pressure treatment is the gold standard. However, surgical intervention is a viable option for those patients who cannot, or refuse, to utilize CPAP.
reported that compression stockings
reduced the number of apneas and hypopnea, perhaps by "prevention of fluid accumulation in the legs during the day, and its nocturnal displacement into the neck at night."
may reduce snoring and daytime sleepiness due to OSA. Since OSA is sometimes caused by hypotonicity (low tone) in the muscles of the throat, playing the didgeridoo may improve symptoms of sleep apnea by exercising muscles of the throat and increasing tone.
A study published in 2009 tested the effect of a set of oropharyngeal exercises developed from exercises used by speech-language pathologists to improve swallowing function. Participants with moderate OSA who performed the exercises every day showed a significant decrease in snoring frequency, snoring intensity, daytime sleepiness, sleep quality score, neck circumference, and AHI score when compared with a control group who performed sham exercises. The improvement in OSA shown by this group was comparable to the improvement shown in patients who use oral appliances to treat this condition.
Although this study was not designed to determine which specific exercises were beneficial, an editorial response to this study in the same journal argues that only 2 of the set of exercises were likely capable of effecting the improvements they reported. These 2 exercises included sucking the tongue upward against the palate for a total of 3 minutes throughout the day, and inflating a balloon by blowing forcefully and then breathing in deeply through the nose, repeated 5 times without removing the balloon from the mouth. The tongue exercise is intended to increase the strength of tongue protrusion, and the balloon exercise is intended to increase the strength of the pharyngeal wall. Although more research is needed to clarify the effects of oropharyngeal exercise on OSA, this recent study suggests a promising new approach to treating the condition.
s (sleeping on the back), are also recommended as a treatment for sleep apnea, largely because the gravitational component is smaller than in the lateral position. A 30 degree elevation of the upper body can be achieved by sleeping in a recliner, an adjustable bed, or a bed wedge placed under the mattress. This approach can easily be used in combination with other treatments and may be particularly effective in very obese people.
" response on the body that happens with each apneic event that increases health risks and consequences in OSA. The fight or flight response causes many hormonal changes in the body; those changes, coupled with the low oxygen saturation level of the blood, cause damage to the body over time.
Although it takes some trial and error, most patients find a combination of treatments which reduce apnea events and improve their overall health, energy, and well-being. Without treatment, the sleep deprivation
and lack of oxygen caused by sleep apnea increases health risks such as cardiovascular disease
, high blood pressure, stroke
, diabetes, clinical depression
, weight gain and obesity
.
The most serious consequence of untreated OSA is to the heart. Sleep apnea sufferers have a 30% higher risk of heart attack or death than those unaffected. In severe and prolonged cases, there are increases in pulmonary pressures that are transmitted to the right side of the heart. This can result in a severe form of congestive heart failure known as cor pulmonale
. One prospective study showed that patients with OSA, compared with healthy controls, initially had statistically significant increases in vascular endothelial growth factor (P=.003) and significantly lower levels of nitrite-nitrate (P=.008), which might be pathogenic factors in the cardiovascular complications of OSA. These factors reversed to normal levels after 12 weeks of treatment by CPAP, but further long-term trials are needed to assess the impact of this therapy.
Elevated arterial pressure (i.e., hypertension
) can be a consequence of OSA syndrome. When hypertension is caused by OSA, it is distinctive in that, unlike most cases (so-called essential hypertension
), the readings do not drop significantly when the individual is sleeping. Stroke
is also known to be associated with OSA.
Obstructive Sleep Apnea
Obstructive sleep apnea event
Sleep apnea
Sleep apnea is a sleep disorder characterized by abnormal pauses in breathing or instances of abnormally low breathing, during sleep. Each pause in breathing, called an apnea, can last from a few seconds to minutes, and may occur 5 to 30 times or more an hour. Similarly, each abnormally low...
and is caused by obstruction of the upper airway
Upper respiratory tract
The upper respiratory tract or upper airway primarily refers to the parts of the respiratory system lying outside of the thorax or above the sternal angle. Another definition commomly used in medicine is the airway above the glottis or vocal cords...
. It is characterized by repetitive pauses in breathing during sleep, despite the effort to breathe, and is usually associated with a reduction in blood oxygen saturation
Oxygen saturation
Oxygen saturation or dissolved oxygen is a relative measure of the amount of oxygen that is dissolved or carried in a given medium. It can be measured with a dissolved oxygen probe such as an oxygen sensor or an optode in liquid media, usually water.It has particular significance in medicine and...
. These pauses in breathing, called apnea
Apnea
Apnea, apnoea, or apnœa is a term for suspension of external breathing. During apnea there is no movement of the muscles of respiration and the volume of the lungs initially remains unchanged...
s (literally, "without breath"), typically last 20 to 40 seconds.
The individual with OSA is rarely aware of having difficulty breathing, even upon awakening. It is recognized as a problem by others witnessing the individual during episodes or is suspected because of its effects on the body (sequelae). OSA is commonly accompanied with snoring
Snoring
Snoring is the vibration of respiratory structures and the resulting sound, due to obstructed air movement during breathing while sleeping. In some cases the sound may be soft, but in other cases, it can be loud and unpleasant...
.
Symptoms may be present for years, even decades without identification, during which time the sufferer may become conditioned to the daytime sleepiness and fatigue associated with significant levels of sleep disturbance. Persons who sleep alone without a long-term human partner may not be told about their sleep disorder symptoms.
Since the muscle tone of the body ordinarily relaxes during sleep, and since, at the level of the throat, the human airway is composed of walls of soft tissue, which can collapse, it is easy to understand how breathing can be obstructed during sleep. Although a very minor degree of OSA is considered to be within the bounds of normal sleep, and many individuals experience episodes of OSA at some point in life, a much smaller percentage of people are afflicted with chronic, severe OSA.
Many people experience episodes of OSA for only a short period of time. This can be the result of an upper respiratory infection that causes nasal congestion, along with swelling of the throat, or tonsillitis that temporarily produces very enlarged tonsils. The Epstein-Barr virus
Epstein-Barr virus
The Epstein–Barr virus , also called human herpesvirus 4 , is a virus of the herpes family and is one of the most common viruses in humans. It is best known as the cause of infectious mononucleosis...
, for example, is known to be able to dramatically increase the size of lymphoid tissue during acute infection, and OSA is fairly common in acute cases of severe infectious mononucleosis
Infectious mononucleosis
Infectious mononucleosis is an infectious, widespread viral...
. Temporary spells of OSA syndrome may also occur in individuals who are under the influence of a drug (such as alcohol) that may relax their body tone excessively and interfere with normal arousal from sleep mechanisms.
Signs and symptoms
Common signs of OSA include unexplained daytime sleepiness, restless sleep, and loud snoringSnoring
Snoring is the vibration of respiratory structures and the resulting sound, due to obstructed air movement during breathing while sleeping. In some cases the sound may be soft, but in other cases, it can be loud and unpleasant...
(with periods of silence followed by gasps). Less common symptoms are morning headaches; insomnia; trouble concentrating; mood changes such as irritability
Irritability
Irritability is an excessive response to stimuli. The term is used for both the physiological reaction to stimuli and for the pathological, abnormal or excessive sensitivity to stimuli; It is usually used to refer to anger or frustration....
, anxiety
Anxiety
Anxiety is a psychological and physiological state characterized by somatic, emotional, cognitive, and behavioral components. The root meaning of the word anxiety is 'to vex or trouble'; in either presence or absence of psychological stress, anxiety can create feelings of fear, worry, uneasiness,...
and depression
Depression (mood)
Depression is a state of low mood and aversion to activity that can affect a person's thoughts, behaviour, feelings and physical well-being. Depressed people may feel sad, anxious, empty, hopeless, helpless, worthless, guilty, irritable, or restless...
; forgetfulness; increased heart rate and/or blood pressure
Blood pressure
Blood pressure is the pressure exerted by circulating blood upon the walls of blood vessels, and is one of the principal vital signs. When used without further specification, "blood pressure" usually refers to the arterial pressure of the systemic circulation. During each heartbeat, BP varies...
; decreased sex drive; unexplained weight gain; increased urination and/or nocturia
Nocturia
Nocturia , also called nycturia , is the need to get up in the night to urinate, thus interrupting sleep. Its occurrence is more frequent in pregnant women and in the elderly...
; frequent heartburn or gastroesophageal reflux disease
Gastroesophageal reflux disease
Gastroesophageal reflux disease , gastro-oesophageal reflux disease , gastric reflux disease, or acid reflux disease is chronic symptoms or mucosal damage caused by stomach acid coming up from the stomach into the esophagus...
; and heavy night sweats.
Adults
In adults, the most typical individual with OSA syndrome suffers from obesityObesity
Obesity is a medical condition in which excess body fat has accumulated to the extent that it may have an adverse effect on health, leading to reduced life expectancy and/or increased health problems...
, with particular heaviness at the face and neck. Obesity is not always present with OSA; in fact, a significant number of adults with normal body mass indices (BMIs) have decrease in muscle tone causing airway collapse and sleep apnea. The cause of this decreased tone is not presently understood. The hallmark symptom of OSA syndrome in adults is excessive daytime sleepiness
Excessive daytime sleepiness
Excessive daytime sleepiness is characterized by persistent sleepiness, and often a general lack of energy, even after apparently adequate night time sleep...
. Typically, an adult or adolescent with severe long-standing OSA will fall asleep for very brief periods in the course of usual daytime activities if given any opportunity to sit or rest. This behavior may be quite dramatic, sometimes occurring during conversations with others at social gatherings.
The hypoxia (absence of oxygen supply) related to OSA may cause changes in the neurons of the hippocampus
Hippocampus
The hippocampus is a major component of the brains of humans and other vertebrates. It belongs to the limbic system and plays important roles in the consolidation of information from short-term memory to long-term memory and spatial navigation. Humans and other mammals have two hippocampi, one in...
and the right frontal cortex. Research using neuro-imaging revealed evidence of hippocampal atrophy in people suffering from OSA. They found that some sufferers have problems in mentally manipulating non-verbal information and in executive function.
Children
Although this so called "hypersomnolence" (excessive sleepiness) may also occur in children, it is not at all typical of young children with sleep apnea. Toddlers and young children with severe OSA instead ordinarily behave as if "over-tired" or "hyperactive." Adults and children with very severe OSA also differ in typical body habitus. Adults are generally heavy, with particularly short and heavy necks. Young children, on the other hand, are generally not only thin, but may have "failure to thriveFailure to thrive
Failure to thrive is a medical term which is used in both pediatric and adult human medicine, as well as veterinary medicine ....
", where growth is reduced. Poor growth occurs for two reasons: the work of breathing is intense enough that calories are burned at high rates even at rest, and the nose and throat are so obstructed that eating is both tasteless and physically uncomfortable. OSA in children, unlike adults, is often caused by obstructive tonsil
Tonsil
Palatine tonsils, occasionally called the faucial tonsils, are the tonsils that can be seen on the left and right sides at the back of the throat....
s and adenoid
Adenoid
Adenoids are a mass of lymphoid tissue situated posterior to the nasal cavity, in the roof of the nasopharynx, where the nose blends into the throat....
s and may sometimes be cured with tonsillectomy
Tonsillectomy
A tonsillectomy is a 3,000-year-old surgical procedure in which the tonsils are removed from either side of the throat. The procedure is performed in response to cases of repeated occurrence of acute tonsillitis or adenoiditis, obstructive sleep apnea, nasal airway obstruction, snoring, or...
and adenoidectomy
Adenoidectomy
Adenoidectomy is the surgical removal of the adenoids. They may be removed for several reasons, including impaired breathing through the nose and chronic infections or earaches. The surgery is less common for adults. It is most often done on an outpatient basis under general anesthesia....
.
This problem can also be caused by excessive weight in children. In this case, the symptoms are more like the symptoms adults feel: restlessness, exhaustion, etc.
Children with OSA may experience learning and memory deficits and OSA has also been linked to lowered childhood IQ scores.
Risk factors
Old age is often accompanied by muscular and neurological loss of muscle tone of the upper airway. Decreased muscle tone is also temporarily caused by chemical depressants; alcoholic drinks and sedative medications being the most common. Permanent premature muscular tonal loss in the upper airway may be precipitated by traumatic brain injuryTraumatic brain injury
Traumatic brain injury , also known as intracranial injury, occurs when an external force traumatically injures the brain. TBI can be classified based on severity, mechanism , or other features...
, neuromuscular disorders
Neuromuscular Disorders
Neuromuscular Disorders is a peer-reviewed medical journal that focuses on neuromuscular disease, including muscular dystrophy, spinal muscular atrophy, and myasthenia. It is the official journal of the World Muscle Society. It was established in 1991 and is published by Elsevier....
, or poor adherence to chemical and or speech-therapy treatments.
Individuals with decreased muscle tone, increased soft tissue around the airway, and structural features that give rise to a narrowed airway are at high risk for OSA. Men, in which the anatomy is typified by increased mass in the torso and neck, are at increased risk of developing sleep apnea, especially through middle age and later. Women suffer typically less frequently and to a lesser degree than do men, owing partially to physiology, but possibly also to differential levels of progesterone
Progesterone
Progesterone also known as P4 is a C-21 steroid hormone involved in the female menstrual cycle, pregnancy and embryogenesis of humans and other species...
. Prevalence in post-menopausal
Menopause
Menopause is a term used to describe the permanent cessation of the primary functions of the human ovaries: the ripening and release of ova and the release of hormones that cause both the creation of the uterine lining and the subsequent shedding of the uterine lining...
women approaches that of men in the same age range. Women are at greater risk for developing OSA during pregnancy
Pregnancy
Pregnancy refers to the fertilization and development of one or more offspring, known as a fetus or embryo, in a woman's uterus. In a pregnancy, there can be multiple gestations, as in the case of twins or triplets...
.
OSA also appears to have a genetic component; those with a family history of it are more likely to develop it themselves. Lifestyle factors such as smoking may also increase the chances of developing OSA as the chemical irritants in smoke tend to inflame the soft tissue of the upper airway and promote fluid retention, both of which can result in narrowing of the upper airway. An individual may also experience or exacerbate OSA with the consumption of alcohol, sedatives, or any other medication that increases sleepiness as most of these drugs are also muscle relaxants.
Epidemiology
OSA is more frequent than central sleep apneaCentral sleep apnea
Central sleep apnea or central sleep apnea syndrome is a sleep-related disorder in which the effort to breathe is diminished or absent, typically for 10 to 30 seconds, either intermittently or in cycles and is usually associated with a reduction in blood oxygen saturation...
and is the most common category of sleep-disordered breathing. It is a common condition in many parts of the world.
If studied carefully in a sleep lab by polysomnography (formal "sleep study"), it is believed by some authorities that approximately 1 in 5 American adults would have at least mild OSA. The precise prevalence of OSA among the adult population in western Europe and North America, however, has not been confidently established. In the mid-1990s it was estimated to be 3-4% of women and 6-7% of men.
Common causes
Most cases of OSA are believed to be caused by:- old age (natural or premature),
- brain injury (temporary or permanent),
- decreased muscle tone,
- increased soft tissue around the airway (sometimes due to obesity), and
- structural features that give rise to a narrowed airway.
Decreased muscle tone can be caused by drugs or alcohol, or it can be caused by neurological problems or other disorders. Some people have more than one of these issues. There is also a theory that long-term snoring might induce local nerve lesions in the pharynx in the same way as long-term exposure to vibration might cause nerve lesions in other parts of the body. Snoring is a vibration of the soft tissues of the upper airways, and studies have shown electrophysiological findings in the nerves and muscles of the pharynx indicating local nerve lesions.
Craniofacial syndromes
There are patterns of unusual facial features that occur in recognizable syndromes. Some of these craniofacial syndromes are genetic, others are from unknown causes. In many craniofacial syndromes, the features that are unusual involve the nose, mouth and jaw, or resting muscle tone, and put the individual at risk for OSA syndrome.Down Syndrome
Down syndrome
Down syndrome, or Down's syndrome, trisomy 21, is a chromosomal condition caused by the presence of all or part of an extra 21st chromosome. It is named after John Langdon Down, the British physician who described the syndrome in 1866. The condition was clinically described earlier in the 19th...
is one such syndrome. In this chromosomal
Chromosome
A chromosome is an organized structure of DNA and protein found in cells. It is a single piece of coiled DNA containing many genes, regulatory elements and other nucleotide sequences. Chromosomes also contain DNA-bound proteins, which serve to package the DNA and control its functions.Chromosomes...
abnormality, several features combine to make the presence of obstructive sleep apnea more likely. The specific features in Down Syndrome that predispose to obstructive sleep apnea include: relatively low muscle tone, narrow nasopharynx
Nasopharynx
The nasopharynx is the uppermost part of the pharynx. It extends from the base of the skull to the upper surface of the soft palate; it differs from the oral and laryngeal parts of the pharynx in that its cavity always remains patent .-Lateral:On its lateral wall is the pharyngeal ostium of the...
, and large tongue. Obesity and enlarged tonsils and adenoids, conditions that occur commonly in the western population, are much more likely to be obstructive in a person with these features than without them. Obstructive sleep apnea does occur even more frequently in people with Down Syndrome than in the general population. A little over 50% of all people with Down Syndrome suffer from obstructive sleep apnea (de Miguel-Díez, et al. 2003), and some physicians advocate routine testing of this group (Shott, et al. 2006).
In other craniofacial syndromes, the abnormal feature may actually improve the airway, but its correction may put the person at risk for obstructive sleep apnea after surgery, when it is modified. Cleft palate syndromes are such an example. During the newborn period, all humans are obligate nasal breathers
Obligate nasal breathing
Obligate nasal breathing is a term used to describe either a physiological or psychological predisposition or obligation to breathe through the nose as opposed to the mouth. The term may be misleading, as it implies that the animal has no choice but to breathe through its nose; however, it is...
. The palate is both the roof of the mouth and the floor of the nose. Having an open palate may make feeding difficult, but generally does not interfere with breathing, in fact - if the nose is very obstructed an open palate may relieve breathing. There are a number of clefting syndromes in which the open palate is not the only abnormal feature, additionally there is a narrow nasal passage - which may not be obvious. In such individuals, closure of the cleft palate- whether by surgery or by a temporary oral appliance, can cause the onset of obstruction.
Skeletal advancement in an effort to physically increase the pharyngeal
Pharynx
The human pharynx is the part of the throat situated immediately posterior to the mouth and nasal cavity, and anterior to the esophagus and larynx. The human pharynx is conventionally divided into three sections: the nasopharynx , the oropharynx , and the laryngopharynx...
airspace is often an option for craniofacial patients with upper airway obstruction and small lower jaws (mandibles). These syndromes include Treacher Collins Syndrome
Treacher Collins syndrome
Treacher Collins syndrome , also known as Treacher Collins–Franceschetti syndrome, or mandibulofacial dysostosis is a rare autosomal dominant congenital disorder characterized by craniofacial deformities, such as absent cheekbones. Treacher Collins syndrome is found in about 1 in 10,000 births, ....
and Pierre Robin Sequence. Mandibular advancement surgery is often just one of the modifications needed to improve the airway, others may include reduction of the tongue, tonsillectomy
Tonsillectomy
A tonsillectomy is a 3,000-year-old surgical procedure in which the tonsils are removed from either side of the throat. The procedure is performed in response to cases of repeated occurrence of acute tonsillitis or adenoiditis, obstructive sleep apnea, nasal airway obstruction, snoring, or...
or modified uvulopalatoplasty
Uvulopalatoplasty
Uvulopalatoplasty is a surgical procedure performed with the aim of reducing or eliminating snoring. It is an out-patient procedure, in which a laser is used to remove parts or all of the uvula at the rear of the mouth. The surgery usually requires three to five visits, with each lasting less than...
.
Post-operative complication
OSA is a also serious post-operative complication that seems to be most frequently associated with pharyngeal flap surgeryPharyngeal flap surgery
Pharyngeal flap surgery is a procedure to correct the airflow during speech. The procedure is common amongpeople with cleft palate and some types of dysarthria.-Pharyngeal flap procedures:...
, compared to other procedures for treatment of velopharyngeal inadequacy
Velopharyngeal inadequacy
Velopharyngeal inadequacy is a malfunction of a velopharyngeal mechanism.The velopharyngeal mechanism is responsible for directing the transmission of sound energy and air pressure in both the oral cavity and the nasal cavity. When this mechanism is impaired in some way, the valve does not fully...
(VPI). In OSA, recurrent interruptions of respiration
Respiration (physiology)
'In physiology, respiration is defined as the transport of oxygen from the outside air to the cells within tissues, and the transport of carbon dioxide in the opposite direction...
during sleep are associated with temporary airway obstruction
Airway obstruction
Airway obstruction is a respiratory problem caused by increased resistance in the bronchioles that reduces the amount of air inhaled in each breath and the oxygen that reaches the pulmonary arteries...
. Following pharyngeal flap surgery, depending on size and position, the flap itself may have an "obturator
Obturator
Obturator may refer to:In medicine:* Obturator artery* Obturator nerve* Obturator vein* Obturator externus muscle* Obturator internus muscle* Obturator membrane* Obturator canal* Obturator foramen...
" or obstructive effect within the pharynx
Pharynx
The human pharynx is the part of the throat situated immediately posterior to the mouth and nasal cavity, and anterior to the esophagus and larynx. The human pharynx is conventionally divided into three sections: the nasopharynx , the oropharynx , and the laryngopharynx...
during sleep, blocking ports of airflow and hindering effective respiration
Respiration (physiology)
'In physiology, respiration is defined as the transport of oxygen from the outside air to the cells within tissues, and the transport of carbon dioxide in the opposite direction...
. There have been documented instances of severe airway obstruction, and reports of post-operative OSA continue to increase as healthcare professionals (i.e. physicians, speech language pathologists
Speech and language pathology
Speech-Language Pathology specializes in communication disorders.The main components of speech production include: phonation, the process of sound production; resonance, opening and closing of the vocal folds; intonation, the variation of pitch; and voice, including aeromechanical components of...
) become more educated about this possible dangerous condition. Subsequently, in clinical practice, concerns of OSA have matched or exceeded interest in speech outcomes following pharyngeal flap surgery.
The surgical treatment for velopalatal insufficiency may cause obstructive sleep apnea syndrome. When velopalatal insufficiency is present, air leaks into the nasopharynx even when the soft palate should close off the nose. A simple test for this condition can be made by placing a tiny mirror at the nose, and asking the subject to say "P". This p sound, a plosive, is normally produced with the nasal airway closed off - all air comes out of the pursed lips, none from the nose. If it is impossible to say the sound without fogging a nasal mirror, there is an air leak - reasonable evidence of poor palatal closure. Speech is often unclear due to inability to pronounce certain sounds. One of the surgical treatments for velopalatal insufficiency involves tailoring the tissue from the back of the throat and using it to purposefully cause partial obstruction of the opening of the nasopharynx
Nasopharynx
The nasopharynx is the uppermost part of the pharynx. It extends from the base of the skull to the upper surface of the soft palate; it differs from the oral and laryngeal parts of the pharynx in that its cavity always remains patent .-Lateral:On its lateral wall is the pharyngeal ostium of the...
. This may actually cause OSA syndrome in susceptible individuals, particularly in the days following surgery, when swelling occurs (see below: Special Situation: Anesthesia and Surgery).
Pathophysiology
The normal sleep/wake cycle in adults is divided into REM (rapid eye movement) sleep, non-REM (NREM) sleep, and consciousness. NREM sleep is further divided into Stages 1, 2 and 3 NREM sleep. The deepest stage (stage 3 of NREM) is required for the physically restorative effects of sleep, and in pre-adolescents this is the period of release of human growth hormone. NREM stage 2 and REM, which combined are 70% of an average person's total sleep time, are more associated with mental recovery and maintenance. During REM sleep in particular, muscle tone of the throat and neck, as well as the vast majority of all skeletal muscles, is almost completely attenuated, allowing the tongue and soft palate/oropharynx to relax, and in the case of sleep apnea, to impede the flow of air to a degree ranging from light snoringSnoring
Snoring is the vibration of respiratory structures and the resulting sound, due to obstructed air movement during breathing while sleeping. In some cases the sound may be soft, but in other cases, it can be loud and unpleasant...
to complete collapse. In the cases where airflow is reduced to a degree where blood oxygen levels fall, or the physical exertion to breathe is too great, neurological mechanisms trigger a sudden interruption of sleep, called a neurological arousal. These arousals rarely result in complete awakening, but can have a significant negative effect on the restorative quality of sleep. In significant cases of OSA, one consequence is sleep deprivation
Sleep deprivation
Sleep deprivation is the condition of not having enough sleep; it can be either chronic or acute. A chronic sleep-restricted state can cause fatigue, daytime sleepiness, clumsiness and weight loss or weight gain. It adversely affects the brain and cognitive function. Few studies have compared the...
due to the repetitive disruption and recovery of sleep activity. This sleep interruption in stage 3 (also called slow-wave sleep
Slow-wave sleep
Slow-wave sleep , often referred to as deep sleep, consists of stages 3 and 4 of non-rapid eye movement sleep, according to the Rechtschaffen & Kales standard of 1968. As of 2008, the American Academy of Sleep Medicine has discontinued the use of stage 4, such that the previous stages 3 and 4 now...
), and in REM sleep, can interfere with normal growth patterns, healing
Healing
Physiological healing is the restoration of damaged living tissue, organs and biological system to normal function. It is the process by which the cells in the body regenerate and repair to reduce the size of a damaged or necrotic area....
, and immune response, especially in children and young adults.
Diagnosis
Diagnosis of OSA is often based on a combination of patient history and tests (lab- or home-based).These tests range, in decreasing order of cost, complexity and tethering of the patient (number and type of channels of data recorded), from lab-attended full polysomnography ("sleep study") down to single-channel home recording. In the USA, these categories are associated with insurance classification from Type I down to Type IV. Reimbursement rules vary among European countries.
Polysomnography
| AHI Apnea-hypopnea index The apnea-hypopnea index is an index of sleep apnea severity that combines apneas and hypopneas. The apneas must last for at least 10 seconds and are associated with a decrease in blood oxygenation... |
Rating |
|---|---|
| <5 | Normal |
| 5-15 | Mild |
| 15-30 | Moderate |
| >30 | Severe |
Polysomnography
Polysomnography
Polysomnography , also known as a sleep study, is a multi-parametric test used in the study of sleep and as a diagnostic tool in sleep medicine. The test result is called a polysomnogram, also abbreviated PSG...
in diagnosing OSA characterizes the pauses in breathing. As in central apnea, pauses are followed by a relative decrease in blood oxygen and an increase in the blood carbon dioxide. Whereas in central sleep apnea the body's motions of breathing stop, in OSA the chest not only continues to make the movements of inhalation, butt the movements typically become even more pronounced. Monitors for airflow at the nose and mouth demosntrate that efforts to breathe are not only present, but that they are often exaggerated. The chest muscles and diaphragm
Thoracic diaphragm
In the anatomy of mammals, the thoracic diaphragm, or simply the diaphragm , is a sheet of internal skeletal muscle that extends across the bottom of the rib cage. The diaphragm separates the thoracic cavity from the abdominal cavity and performs an important function in respiration...
contract and the entire body may thrash and struggle.
An "event" can be either an apnea, characterised by complete cessation of airflow for at least 10 seconds, or a hypopnea in which airflow decreases by 50 percent for 10 seconds or decreases by 30 percent if there is an associated decrease in the oxygen saturation or an arousal from sleep . To grade the severity of sleep apnea, the number of events per hour is reported as the apnea-hypopnea index
Apnea-hypopnea index
The apnea-hypopnea index is an index of sleep apnea severity that combines apneas and hypopneas. The apneas must last for at least 10 seconds and are associated with a decrease in blood oxygenation...
(AHI). An AHI of less than 5 is considered normal. An AHI of 5-15 is mild; 15-30 is moderate and more than 30 events per hour characterizes severe sleep apnea.
Home oximetry
In patients who are at high likelihood of having OSA, a randomized controlled trialRandomized controlled trial
A randomized controlled trial is a type of scientific experiment - a form of clinical trial - most commonly used in testing the safety and efficacy or effectiveness of healthcare services or health technologies A randomized controlled trial (RCT) is a type of scientific experiment - a form of...
found that home oximetry (a non-invasive method of monitoring blood oxygenation) may be adequate and easier to obtain than formal polysomnography. High probability patients were identified by an Epworth Sleepiness Scale
Epworth Sleepiness Scale
The Epworth Sleepiness Scale is a scale intended to measure daytime sleepiness that is measured by use of a very short questionnaire. This can be helpful in diagnosing sleep disorders...
(ESS) score of 10 or greater and a Sleep Apnea Clinical Score (SACS) of 15 or greater. Home oximetry, however, does not measure apneic events or respiratory event-related arousals and thus does not produce an AHI value.
Treatment
There are a variety of treatments for OSA; use is determined by an individual patient's medical history, the severity of the disorder and, most importantly, the specific cause of the obstruction.In acute infectious mononucleosis
Infectious mononucleosis
Infectious mononucleosis is an infectious, widespread viral...
, for example, although the airway may be severely obstructed in the first 2 weeks of the illness, the presence of lymphoid tissue (suddenly enlarged tonsils and adenoids) blocking the throat is usually only temporary. A course of anti-inflammatory steroids such as prednisone
Prednisone
Prednisone is a synthetic corticosteroid drug that is particularly effective as an immunosuppressant drug. It is used to treat certain inflammatory diseases and some types of cancer, but has significant adverse effects...
(or another kind of glucocorticoid drug) is often given to reduce this lymphoid tissue. Although the effects of the steroids are short term, in most affected individuals, the tonsillar and adenoidal enlargement are also short term, and will be reduced on its own by the time a brief course of steroids is completed. In unusual cases where the enlarged lymphoid tissue persists after resolution of the acute stage of the Epstein-Barr infection, or in which medical treatment with anti-inflammatory steroids does not adequately relieve breathing, tonsillectomy and adenoidectomy
Adenoidectomy
Adenoidectomy is the surgical removal of the adenoids. They may be removed for several reasons, including impaired breathing through the nose and chronic infections or earaches. The surgery is less common for adults. It is most often done on an outpatient basis under general anesthesia....
may be urgently required.
OSA in children is sometimes due to chronically enlarged tonsils and adenoids. Tonsillectomy and adenoidectomy is curative. The operation may be far from trivial, especially in the worst apnea cases, in which growth is retarded and abnormalities of the right heart may have developed. Even in these extreme cases, the surgery tends to cure not only the apnea and upper airway obstruction, but allows normal subsequent growth and development. Once the high end-expiratory pressures are relieved, the cardiovascular complications reverse themselves. The postoperative period in these children requires special precautions (see "Surgery and obstructive sleep apnea syndrome" below).
The treatment of OSA in adults with poor oropharyngeal
Oropharynx
The Oropharynx reaches from the Uvula to the level of the hyoid bone.It opens anteriorly, through the isthmus faucium, into the mouth, while in its lateral wall, between the two palatine arches, is the palatine tonsil....
airways secondary to heavy upper body type is varied. Unfortunately, in this most common type of OSA, unlike some of the cases discussed above, reliable cures are not the rule.
Some treatments involve lifestyle changes, such as avoiding alcohol and medications that relax the central nervous system (for example, sedatives and muscle relaxants), losing weight, and quitting smoking. Some people are helped by special pillows or devices that keep them from sleeping on their backs, or oral appliances to keep the airway open during sleep. For those cases where these conservative methods are inadequate, doctors can recommend continuous positive airway pressure
Continuous positive airway pressure
Positive airway pressure is a mode of respiratory ventilation used primarily in the treatment of sleep apnea, for which it was first developed. PAP ventilation is also commonly used for those who are critically ill in hospital with respiratory failure, and in newborn infants...
(CPAP), in which a face mask is attached to a tube and a machine that blows pressurized air into the mask and through the airway to keep it open. There are also surgical procedures intended to remove and tighten tissue and widen the airway, but none has been reproducibly successful. Some individuals may need a combination of therapies to successfully treat their condition.
Physical intervention
The most widely used current therapeutic intervention is positive airway pressure whereby a breathing machine pumps a controlled stream of air through a mask worn over the nose, mouth, or both. The additional pressure splints or holds open the relaxed muscles, just as air in a balloonBalloon
A balloon is an inflatable flexible bag filled with a gas, such as helium, hydrogen, nitrous oxide, oxygen, or air. Modern balloons can be made from materials such as rubber, latex, polychloroprene, or a nylon fabric, while some early balloons were made of dried animal bladders, such as the pig...
inflates it. There are several variants:
- (CPAPContinuous positive airway pressurePositive airway pressure is a mode of respiratory ventilation used primarily in the treatment of sleep apnea, for which it was first developed. PAP ventilation is also commonly used for those who are critically ill in hospital with respiratory failure, and in newborn infants...
), or continuous positive airway pressure, in which a computer controlled air flow generator, generates an airstream at a constant pressure. This pressure is prescribed by the patient's physician, based on an overnight test or titrationTitration (disambiguation)Titration is a common laboratory method of quantitative chemical analysis that is used to determine the unknown concentration of a known reactant.Titration may also refer to:* Acid-base titration, based on the neutralization reaction...
. Newer CPAP models are available which slightly reduce pressure upon exhalation to increase patient comfort and compliance. CPAP is the most common treatment for obstructive sleep apnea. - (VPAP), or variable positive airway pressure, also known as bilevel or BiPAP, uses an electronic circuit to monitor the patient's breathing, and provides two different pressures, a higher one during inhalationInhalationInhalation is the movement of air from the external environment, through the air ways, and into the alveoli....
and a lower pressure during exhalationExhalationExhalation is the movement of air out of the bronchial tubes, through the airways, to the external environment during breathing....
. This system is more expensive, and is sometimes used with patients who have other coexisting respiratory problems and/or who find breathing out against an increased pressure to be uncomfortable or disruptive to their sleep. - (APAP), or automatic positive airway pressure, is the newest form of such treatment. An APAP machine incorporates pressure sensors and a computer which continuously monitors the patient's breathing performance. Review in: ACP J Club. 2005 Jul-Aug;143(1):21 It adjusts pressure continuously, increasing it when the user is attempting to breathe but cannot, and decreasing it when the pressure is higher than necessary. Although FDA approved, these devices are still considered experimental by many, and are not covered by most insurance plans under a APAP specific code. Auto CPAP machines can be covered at rate of a CPAP machine.
A second type of physical intervention, a Mandibular advancement splint
Mandibular advancement splint
A mandibular splint or mandibular advancement splint is a device worn in the mouth that is used to treat obstructive sleep apnea and snoring...
(MAS), is sometimes prescribed for mild or moderate sleep apnea sufferers. The device is a mouthguard similar to those used in sports to protect the teeth. For apnea patients, it is designed to hold the lower jaw slightly down and forward relative to the natural, relaxed position. This position holds the tongue farther away from the back of the airway, and may be enough to relieve apnea or improve breathing for some patients.
The FDA accepts only 16 oral appliances for the treatment of sleep apnea. A listing is available at its website.
Oral appliance therapy is less effective than CPAP, but is more 'user friendly'. Side-effects are common, but rarely is the patient aware of them.
Pharmaceuticals
There are no effective drug-based treatments for obstructive sleep apnea that have FDA approval. However, a clinical trial of mirtazapineMirtazapine
Mirtazapine is a tetracyclic antidepressant used primarily in the treatment of depression. It is also sometimes used as a hypnotic, antiemetic, and appetite stimulant, and for the treatment of anxiety, among other indications...
, has shown early promise at the University of Illinois at Chicago
University of Illinois at Chicago
The University of Illinois at Chicago, or UIC, is a state-funded public research university located in Chicago, Illinois, United States. Its campus is in the Near West Side community area, near the Chicago Loop...
. This small, early study found a 50% decrease in occurrence of apnea episodes and 28% decrease in sleep disruptions in 100% of patients (twelve patients) taking them. Nonetheless, due to the risk of weight gain and sedation (two risk factors and consequences of sleep apnea) it is not recommended. An effort to improve the effects of mirtazapine by combining it with another existing medication was cancelled during Phase IIa trials in 2006. Dr. David Carley and Dr. Miodrag Radulovacki, the sleep researchers who were behind the initial clinical trial of mirtazapine are now working on a new treatment that consists of two other existing medications taken off-label together for treatment of sleep apnea.
Other serotonin effecting agents that have been explored unsuccessfully as a treatment for apnea include fluoxetine
Fluoxetine
Fluoxetine is an antidepressant of the selective serotonin reuptake inhibitor class. It is manufactured and marketed by Eli Lilly and Company...
, tryptophan
Tryptophan
Tryptophan is one of the 20 standard amino acids, as well as an essential amino acid in the human diet. It is encoded in the standard genetic code as the codon UGG...
and protriptyline
Protriptyline
Protriptyline is a tricyclic antidepressant , specifically a secondary amine, indicated for the treatment of depression and ADHD...
.
Oral administration of the methylxanthine theophylline
Theophylline
Theophylline, also known as dimethylxanthine, is a methylxanthine drug used in therapy for respiratory diseases such as COPD and asthma under a variety of brand names. Because of its numerous side-effects, the drug is now rarely administered for clinical use. As a member of the xanthine family, it...
(chemically similar to caffeine
Caffeine
Caffeine is a bitter, white crystalline xanthine alkaloid that acts as a stimulant drug. Caffeine is found in varying quantities in the seeds, leaves, and fruit of some plants, where it acts as a natural pesticide that paralyzes and kills certain insects feeding on the plants...
) can reduce the number of episodes of apnea, but can also produce side effects such as heart palpitations and insomnia
Insomnia
Insomnia is most often defined by an individual's report of sleeping difficulties. While the term is sometimes used in sleep literature to describe a disorder demonstrated by polysomnographic evidence of disturbed sleep, insomnia is often defined as a positive response to either of two questions:...
. Theophylline is generally ineffective in adults with OSA, but is sometimes used to treat central sleep apnea (see below), and infant
Infant
A newborn or baby is the very young offspring of a human or other mammal. A newborn is an infant who is within hours, days, or up to a few weeks from birth. In medical contexts, newborn or neonate refers to an infant in the first 28 days after birth...
s and children with apnea.
When other treatments do not completely treat the OSA, drugs are sometimes prescribed to treat a patient's daytime sleepiness or somnolence
Somnolence
Somnolence is a state of near-sleep, a strong desire for sleep, or sleeping for unusually long periods . It has two distinct meanings, referring both to the usual state preceding falling asleep, and the chronic condition referring to being in that state independent of a circadian rhythm...
. These range from stimulants such as amphetamine
Amphetamine
Amphetamine or amfetamine is a psychostimulant drug of the phenethylamine class which produces increased wakefulness and focus in association with decreased fatigue and appetite.Brand names of medications that contain, or metabolize into, amphetamine include Adderall, Dexedrine, Dextrostat,...
s to modern anti-narcoleptic
Narcolepsy
Narcolepsy is a chronic sleep disorder, or dyssomnia, characterized by excessive sleepiness and sleep attacks at inappropriate times, such as while at work. People with narcolepsy often experience disturbed nocturnal sleep and an abnormal daytime sleep pattern, which often is confused with insomnia...
medicines. The anti-narcoleptic
Narcolepsy
Narcolepsy is a chronic sleep disorder, or dyssomnia, characterized by excessive sleepiness and sleep attacks at inappropriate times, such as while at work. People with narcolepsy often experience disturbed nocturnal sleep and an abnormal daytime sleep pattern, which often is confused with insomnia...
medicine modafinil
Modafinil
Modafinil is an analeptic drug manufactured by Cephalon, and is approved by the U.S. Food and Drug Administration for the treatment of narcolepsy, shift work sleep disorder, and excessive daytime sleepiness associated with obstructive sleep apnea...
is seeing increased use in this role .
In most cases, weight loss will reduce the number and severity of apnea episodes. In the morbidly obese, a major loss of weight (such as what occurs after bariatric surgery
Bariatric surgery
Bariatric surgery includes a variety of procedures performed on people who are obese. Weight loss is achieved by reducing the size of the stomach with an implanted medical device or through removal of a portion of the stomach or by resecting and re-routing the small intestines...
) can sometimes cure the condition.
Neurostimulation
Some researchers believe that OSA is at root a neurological condition, in which nerves that control the tongue and soft palate fail to sufficiently stimulate those muscles, leading to over-relaxation and airway blockage. A few experiments and trial studies have explored the use of pacemakers and similar devices, programmed to detect breathing effort and deliver gentle electrical stimulation to the muscles of the tongue.This is not a common mode of treatment for OSA patients as of 2004, but it is an active field of research.
Surgical intervention
A number of different surgeries are available to improve the size or tone of a patient's airway. For decades, tracheostomy was the only effective treatment for sleep apnea. It is used today only in rare, intractable cases that have withstood other attempts at treatment. Modern operations employ one or more of several options, tailored to each patient's needs. Success rates are directly proportional to the accuracy in the initial diagnosis of the site of obstruction.- Nasal surgery, including turbinectomyTurbinectomyTurbinectomy is removal of some or all of the turbinate bones of the nose attached to mucous membranes. It has been used to relieve nasal obstruction, but side-effects include removal of nerves that would report the passage of air....
(removal or reduction of a nasal turbinateTurbinateIn anatomy, a nasal concha is a long, narrow and curled bone shelf that protrudes into the breathing passage of the nose...
), or straightening of the nasal septumNasal septumThe nasal septum separates the left and right airways in the nose, dividing the two nostrils.It is depressed by the Depressor septi nasi muscle.-Composition:The fleshy external end of the nasal septum is sometimes also called columella....
, in patients with nasal obstruction or congestion which reduces airway pressure and complicates OSA. - TonsillectomyTonsillectomyA tonsillectomy is a 3,000-year-old surgical procedure in which the tonsils are removed from either side of the throat. The procedure is performed in response to cases of repeated occurrence of acute tonsillitis or adenoiditis, obstructive sleep apnea, nasal airway obstruction, snoring, or...
and/or adenoidectomyAdenoidectomyAdenoidectomy is the surgical removal of the adenoids. They may be removed for several reasons, including impaired breathing through the nose and chronic infections or earaches. The surgery is less common for adults. It is most often done on an outpatient basis under general anesthesia....
in an attempt to increase the size of the airway. - Removal or reduction of parts of the soft palateSoft palateThe soft palate is the soft tissue constituting the back of the roof of the mouth. The soft palate is distinguished from the hard palate at the front of the mouth in that it does not contain bone....
and some or all of the uvulaUvulaThe palatine uvula, usually referred to as simply the uvula , is the conic projection from the posterior edge of the middle of the soft palate, composed of connective tissue containing a number of racemose glands, and some muscular fibers .-Function in language:The uvula plays a role in the...
, such as uvulopalatopharyngoplastyUvulopalatopharyngoplastyUvulopalatopharyngoplasty is a surgical procedure used to remove tissue in the throat...
(UPPP) or laser-assisted uvulopalatoplasty (LAUP). Modern variants of this procedure sometimes use radiofrequency waves to heat and remove tissue. - Reduction of the tongue base, either with laser excision or radiofrequency ablationRadiofrequency ablationRadio frequency ablation is a medical procedure where part of the electrical conduction system of the heart, tumor or other dysfunctional tissue is ablated using the heat generated from the high frequency alternating current to treat a medical disorder...
. - Genioglossus AdvancementGenioglossus AdvancementGenioglossus Advancement , is a surgical procedure where the base of the tongue is pulled forward, usually to increase airway size due to deformity or a sleep breathing disorder - See Sleep Apnea....
, in which a small portion of the lower jaw that attaches to the tongue is moved forward, to pull the tongue away from the back of the airway. - Hyoid Suspension, in which the hyoid boneHyoid boneThe hyoid bone is a horseshoe-shaped bone situated in the anterior midline of the neck between the chin and the thyroid cartilage. At rest, it lies at the level of the base of the mandible in the front and the third cervical vertebra behind.Unlike other bones, the hyoid is only distantly...
in the neck, another attachment point for tongue muscles, is pulled forward in front of the larynxLarynxThe larynx , commonly called the voice box, is an organ in the neck of amphibians, reptiles and mammals involved in breathing, sound production, and protecting the trachea against food aspiration. It manipulates pitch and volume...
. - Maxillomandibular advancementMaxillomandibular advancementMaxillomandibular Advancement or orthognathic surgery, also sometimes called Bimaxillary Advancement , or Maxillomandibular Osteotomy , is a surgical procedure which moves the jaw top and bottom forward....
(MMA). MMA is the most effective sleep apnea surgical procedure currently available, with reduction of the AHI to less than 15 in over 90% of patients, and reduction of AHI to <5 in ~45% of patients. MMA was once thought to be fairly invasive, but has shown to be less painful, in general, than a UPPP soft palate procedure. The associated surgical risks are low, including bleeding, infection, malocclusion, and permanent numbness of the chin and lip. In general, patient perceptions of surgical outcome have been very favorable.
The role of surgery in the treatment of sleep apnea has been questioned repeatedly as the long term success rate of the procedures has come into question. Patient selection in the past was oftentimes quite poor, resulting in poor overall results. Potential surgical candidates should now be extensively examined to assure the site of obstruction is clearly evident prior to any surgical intervention.The patient's age, weight and other factors may make them a bad candidate for surgery. When a patient can tolerate it, positive air pressure treatment is the gold standard. However, surgical intervention is a viable option for those patients who cannot, or refuse, to utilize CPAP.
Compression stockings
A small randomized controlled trialRandomized controlled trial
A randomized controlled trial is a type of scientific experiment - a form of clinical trial - most commonly used in testing the safety and efficacy or effectiveness of healthcare services or health technologies A randomized controlled trial (RCT) is a type of scientific experiment - a form of...
reported that compression stockings
Compression stockings
Compression stockings and socks are specialised hosiery items designed to increase blood circulation. Their main theraputic purpose is to provide graduated pressure on the lower leg and foot and, in some cases, the thigh, to alleviate circulatory problems such as edema, phlebitis and...
reduced the number of apneas and hypopnea, perhaps by "prevention of fluid accumulation in the legs during the day, and its nocturnal displacement into the neck at night."
Oropharyngeal muscle exercises
One study showed that playing the didgeridooDidgeridoo
The didgeridoo is a wind instrument developed by Indigenous Australians of northern Australia around 1,500 years ago and still in widespread usage today both in Australia and around the world. It is sometimes described as a natural wooden trumpet or "drone pipe"...
may reduce snoring and daytime sleepiness due to OSA. Since OSA is sometimes caused by hypotonicity (low tone) in the muscles of the throat, playing the didgeridoo may improve symptoms of sleep apnea by exercising muscles of the throat and increasing tone.
A study published in 2009 tested the effect of a set of oropharyngeal exercises developed from exercises used by speech-language pathologists to improve swallowing function. Participants with moderate OSA who performed the exercises every day showed a significant decrease in snoring frequency, snoring intensity, daytime sleepiness, sleep quality score, neck circumference, and AHI score when compared with a control group who performed sham exercises. The improvement in OSA shown by this group was comparable to the improvement shown in patients who use oral appliances to treat this condition.
Although this study was not designed to determine which specific exercises were beneficial, an editorial response to this study in the same journal argues that only 2 of the set of exercises were likely capable of effecting the improvements they reported. These 2 exercises included sucking the tongue upward against the palate for a total of 3 minutes throughout the day, and inflating a balloon by blowing forcefully and then breathing in deeply through the nose, repeated 5 times without removing the balloon from the mouth. The tongue exercise is intended to increase the strength of tongue protrusion, and the balloon exercise is intended to increase the strength of the pharyngeal wall. Although more research is needed to clarify the effects of oropharyngeal exercise on OSA, this recent study suggests a promising new approach to treating the condition.
Positional treatments
Many people benefit from sleeping at a 30 degree elevation of the upper body or higher, as if in a recliner. Doing so helps prevent the gravitational collapse of the airway. Lateral positions (sleeping on a side), as opposed to supine positionSupine position
The supine position is a position of the body: lying down with the face up, as opposed to the prone position, which is face down, sometimes with the hands behind the head or neck. When used in surgical procedures, it allows access to the peritoneal, thoracic and pericardial regions; as well as the...
s (sleeping on the back), are also recommended as a treatment for sleep apnea, largely because the gravitational component is smaller than in the lateral position. A 30 degree elevation of the upper body can be achieved by sleeping in a recliner, an adjustable bed, or a bed wedge placed under the mattress. This approach can easily be used in combination with other treatments and may be particularly effective in very obese people.
Prognosis
Many studies indicate that it is the effect of a "fight or flightFight or Flight
Fight or Flight may refer to:* Fight-or-flight response, the biological response of animals to acute stress* "Fight or Flight!" , a song off the album Aneurythm by the American hard rock band Living Syndication...
" response on the body that happens with each apneic event that increases health risks and consequences in OSA. The fight or flight response causes many hormonal changes in the body; those changes, coupled with the low oxygen saturation level of the blood, cause damage to the body over time.
Although it takes some trial and error, most patients find a combination of treatments which reduce apnea events and improve their overall health, energy, and well-being. Without treatment, the sleep deprivation
Sleep deprivation
Sleep deprivation is the condition of not having enough sleep; it can be either chronic or acute. A chronic sleep-restricted state can cause fatigue, daytime sleepiness, clumsiness and weight loss or weight gain. It adversely affects the brain and cognitive function. Few studies have compared the...
and lack of oxygen caused by sleep apnea increases health risks such as cardiovascular disease
Cardiovascular disease
Heart disease or cardiovascular disease are the class of diseases that involve the heart or blood vessels . While the term technically refers to any disease that affects the cardiovascular system , it is usually used to refer to those related to atherosclerosis...
, high blood pressure, stroke
Stroke
A stroke, previously known medically as a cerebrovascular accident , is the rapidly developing loss of brain function due to disturbance in the blood supply to the brain. This can be due to ischemia caused by blockage , or a hemorrhage...
, diabetes, clinical depression
Clinical depression
Major depressive disorder is a mental disorder characterized by an all-encompassing low mood accompanied by low self-esteem, and by loss of interest or pleasure in normally enjoyable activities...
, weight gain and obesity
Obesity
Obesity is a medical condition in which excess body fat has accumulated to the extent that it may have an adverse effect on health, leading to reduced life expectancy and/or increased health problems...
.
The most serious consequence of untreated OSA is to the heart. Sleep apnea sufferers have a 30% higher risk of heart attack or death than those unaffected. In severe and prolonged cases, there are increases in pulmonary pressures that are transmitted to the right side of the heart. This can result in a severe form of congestive heart failure known as cor pulmonale
Cor pulmonale
Cor pulmonale or pulmonary heart disease is enlargement of the right ventricle of the heart as a response to increased resistance or high blood pressure in the lungs ....
. One prospective study showed that patients with OSA, compared with healthy controls, initially had statistically significant increases in vascular endothelial growth factor (P=.003) and significantly lower levels of nitrite-nitrate (P=.008), which might be pathogenic factors in the cardiovascular complications of OSA. These factors reversed to normal levels after 12 weeks of treatment by CPAP, but further long-term trials are needed to assess the impact of this therapy.
Elevated arterial pressure (i.e., hypertension
Hypertension
Hypertension or high blood pressure is a cardiac chronic medical condition in which the systemic arterial blood pressure is elevated. What that means is that the heart is having to work harder than it should to pump the blood around the body. Blood pressure involves two measurements, systolic and...
) can be a consequence of OSA syndrome. When hypertension is caused by OSA, it is distinctive in that, unlike most cases (so-called essential hypertension
Essential hypertension
Essential hypertension is the form of hypertension that by definition, has no identifiable cause. It is the most common type of hypertension, affecting 95% of hypertensive patients, it tends to be familial and is likely to be the consequence of an interaction between environmental and genetic...
), the readings do not drop significantly when the individual is sleeping. Stroke
Stroke
A stroke, previously known medically as a cerebrovascular accident , is the rapidly developing loss of brain function due to disturbance in the blood supply to the brain. This can be due to ischemia caused by blockage , or a hemorrhage...
is also known to be associated with OSA.
See also
- Marfan syndromeMarfan syndromeMarfan syndrome is a genetic disorder of the connective tissue. People with Marfan's tend to be unusually tall, with long limbs and long, thin fingers....
- Respiratory disturbance indexRespiratory Disturbance IndexThe respiratory disturbance index — or respiratory distress Index — is an formula used in reporting polysomnography findings. Like the apnea-hypopnea index , it reports on respiratory events during sleep, but unlike the AHI, it also includes respiratory-effort related arousals...
(RDI) - Upper airway resistance syndrome, related condition whose existence is questioned
External links
American Sleep Apnea AssociationObstructive Sleep Apnea
Obstructive sleep apnea event