- Email: [email protected]
Diagnosis and management of sleep apnea syndrome
clinical CORNERSTONE
9 SLEEP DISORDERS
- Vol. 2 No. 5
Diagnosis and Management of Sleep Apnea Syndrome Meir
H. Kryger,
MD,
FRCPC
Professor of Medicine University of Manitoba Winnipeg, Manitoba Canada
Sleep apnea is the cessation of breathing during sleep. These episodes result in hypoxemia and sleep disruption;.. thus the consequences are both cardiorespiratory and neural. Sleep apnea syndrome is defined by a constellation of signs and symptoms, with the main presenting symptom being excessive daytime sleepiness. A diagnosis requires documentation of episodes of abnormal breathing during sleep. This disorder, once thought to be very rare, is so common that it is unlikely that any busy clinician has not encountered a case. Facilities for the evaluation of sleep breathing disorders are now available in most communities. With the introduction of continuous positive airway pressure and other treatments, most patients have complete resolution of their disabling symptoms.
PATHOPHYSIOLOGY
may have a respiratory control system that is overly sensitive, which overshoots and undershoots, and thus excessive breathing (hyperpnea) alternates with episodes of hypoventilation or cessation of
Repetitive episodes of cessation of breathing can be caused by a reduction of neural impulses from the central nervous system to the muscles of respiration or by upper airway obstruction that manifests during sleep. The former results in central sleep apnea, whereas the latter results in obstructive sleep apneakypopnea syndrome, and it is encountered much more frequently in clinical practice.
Central Sleep Apnea Decreased neural impulses from the central nervous system to the muscles of respiration generally reflect either structural or physiologic abnormalities in the respiratory control system. Structural lesions in the brain stem, the site of the respiratory pacemakers, are an example of disorders that result in blunted control of breathing, causing repetitive episodes of central apnea. For many types of central apnea-for example, congenital hypoventilation syndromes-the cause of the blunting of the drive to breathe is unknown. Paradoxically, patients who have an increased drive to breathe
breathing (hypopnea or apnea). This type of abnormality has been documented in patients with Cheyne-Stokes breathing caused by heart failure and those living at high altitudes. Such patients are much more likely to present with insomnia than are patients with obstructive apnea, who usually complain about excessive daytime sleepiness.
Obstructive Sleep Apnea Obstructive sleep apnea, the more common type of apnea, is caused by obstruction in the upper airway.
39
clinical CORNERSTONE
.
SLEEP DISORDERS
.
Vol.2 No. 5
Daytime
Nighttime
Sleepiness
Snoring
Impaired concentration
Observed apnea
Irritability
Choking
Depression symptoms
Sweating
Decreased libido
Nocturia
In the vast majority
of patients,
the obstruction
EPIDEMIOLOGY Obstructive sleep apnea was once thought to be extremely rare. We now know that it is a quite common condition affecting approximately 4% of adult men and 2% of adult women. Obstructive sleep apnea runs in families, and it affects all agegroups. In adults this disorder commonly occurs in males, the morbidly obese, and persons with cardiovascular disease, for example, arterial hypertension. In children, enlarged tonsils or adenoids can cause obstructive sleep apnea. Central sleep apnea is much less common. For the remainder of this review I will focus on obstructive sleep apnea.
is
related to obesity, which decreases the size of the pharyngeal airway, or..by anatomical lesions in the upper airway, for example, retrognathia or enlarged tonsils. CONSEQUENCES Apnea, whether central or obstructive, results in hypoventilation (which leads to hypoxemia), changes in autonomic nervous system tone (which can lead to bradycardia and other arrhythmias during sleep), and systemic hypertension. To start breathing again, most patients awaken briefly,
CLINICAL PRESENTATION Including a family member or bed partner in the interview with the patient can be extremely valuable. Indeed, very often the evaluation of the patient may have started because such a person witnessed the patient’s distressing symptoms, including breathing interruptions. The snoring of the patient may even interfere with the bed partner’s ability to sleep. Obstructive sleep apnea can affect so many different systems that patients may present with problems that, at first glance, do not appear to be related to obstructive sleep apnea. Table I outlines the symptoms that may indicate obstructive sleep apnea. Unless the clinician incorporates a sleep history into the routine clinical evaluation, the disorder will be missed in many patients.
which reestablishes ventilation. These patients have hundreds of arousals each night, resulting in repetitive cardiorespiratory changes during sleep or unstable fragmented sleep. These 2 consequences result in the clinical features at presentation, such as neural symptoms like daytime sleepiness. The cardiorespiratory changes result in an increased risk of arterial hypertension, coronary artery disease, and stroke. The most severely affected patients may develop respiratory failure (both asleep and awake) and car pulmonale (heart failure caused by respiratory failure). The most severely affected patients are said to have pickwickian syndrome, also called obesity hypoventilation syndrome.
Daytime Symptoms By far the most common presentation of patients with sleep apnea is excessive daytime sleepiness.
40
clinicnl CORNERSTONE
l
Enlarged tonsils and adenoids
o Increased neck collar size (243 cm or 17 in)
l
Nasal obstruction
0 Retrognathia
0 Peripheral edema
l
Obesity
l
Macroglossia
l
Sleep apnea
0 Insufficient l
and overjet
sleep
Unwanted effects of drugs
These patients fall asleep at the wrong time and the wrong place. They fall asleep at the movies, in front of the television, and sometimes even at work or behind the wheel of a motor vehicle. They often will have poor memory or difficulty concentrating, and they may demonstrate poor performance at work or school. The patient or family member may relate that the problem has caused moodiness
l
Hypothyroidism
l
Narcolepsy/cataplexy
l
Movement
= SLEEP DISORDERS
a Vol. 2 No. 5
disorders
with quieter or silent periods when the patient is obviously not breathing. Waking up with headache, choking, nocturia, and diaphoresis are other, less common, symptoms.
PHYSICAL
EXAMINATION
The vast majority of patients with obstructive sleep apnea are obese or have an upper airway compromised by an abnormality of the jaw (micrognathia or retrognathia). Younger patients may have enlarged tonsils. In some patients an overjet can be confirmed on examination, whereas for others the reason for airway obstrnction is not entirely clear on physical examination. These patients must have the entire upper airway, including the nose, examined. Some patients may require evaluation by an ear, nose, and throat specialist. In the most severely affected patients there will be evidence of right heart failure. Findings on physical examination are summarized in Table II.
and irritability, and they may indicate that the abnormal mood and sleepiness of the patient have resulted in family strife. Patients are often diagnosed with depression. Decreased libido is also a common symptom. The most severely affected individuals may develop respiratory failure or right heart failure and may present with peripheral edema and polycythemia.
DIFFERENTIAL
DIAGNOSIS
Several other conditions can result in excessive daytime sleepiness (Table III). Hypothyroidism has some symptoms that overlap with those of sleep apnea and may actually cause sleep apnea. Approximately 2% to 3% of apnea patients will be found to have hypothyroidism. Cataplexy, the sudden loss of muscle tone with emotion, is found in narcolepsy but not in obstructive sleep apnea. Hypnagogic hallucinations, dream-like visual or
Nighttime Symptoms Some patients present because a bed partner or family member has observed them snoring loudly and ceasing to breathe during sleep. The snoring has a distressing quality, with loud snoring alternating
41
clinical CORNERSTONE
1 SLEEP DISORDERS
1 Vol. 2 No. 5
INTEGRATING LABORATORY
auditory hallucinations occurring at sleep onset, which are common in narcolepsy, can also occur in some persons with obstructive sleep apnea. Many patients with narcolepsy feel refreshed after a short nap, whereas those with obstructive sleep apnea usually do not. Movement disorders, such as periodic movements in sleep, can lead to insomnia and excessive daytime sleepiness. Movement disorders are discussed elsewhere in this issue in the article by Dr. Mahowald.
DIAGNOSTIC
CLINICALAND DATA
Sleep apnea syndrome is present when clinical features combine with more than 5 abnormal breathing events per hour of sleep. The severity of apnea is determined by grading the severity of the key symptom (daytime sleepiness) and the severity of the RDI (see previous text).
TESTS
If a patient is suspected of having obstructive sleep apnea, then documentation of the disorder is required. In general, this means that the patient will have to undergo an overnight sleep study that monitors cardiorespiratory and electroencephalographic variables, and documents periodic movements in sleep, such as activity of the legs. The technology for gathering these data is changing rapidly, and computerized systems are being used more and more often. An overnight sleep study can answer the following questions: How often does the patient have obstructed breathing events per hour of sleep? These abnormal breathing events could be apneas, hypopneas, or increased efforts to breathe (for example, snorts). The results of the testing are expressed as the respiratory disturbance index (RDI), and it includes apneas, hypopneas, and arousals related to respiratory effort per hour of sleep. What is the patient’s sleep structure? The number of arousals per hour of sleep and the sleep architecture (distribution of sleep stages) are also usually determined in an overnight sleep study. Patients with sleep apnea have fragmented sleep with many arousals. They usually show a reduction in the amount of slow-wave sleep and frequently show a reduction in rapid-eye-movement sleep. What is the nature of the patient’s movements during sleep? The movement index is derived from the number of contractions per hour of the anterior tibialis muscle. Many patients with obstructive sleep apnea also have periodic movements in sleep, an extremely common condition. This topic is discussed more thoroughly elsewhere in this issue in the article by Dr. Roth.
Severity of Sleepiness Sleepiness may be considered mild when it is present during activities requiring little attention (eg, watching television), moderate during activities requiring some attention (eg, business meetings), or severe during activities requiring active attention (eg, operating a motor vehicle).
Severity of the Sleep Breathing Disorder Sleep obstructive events are considered mild when the RDI falls between 5 and 15, moderate is between 15 and 30, and severe is in excess of 30 per hour. The overall severity of the syndrome is the more severe of the 2 (sleepiness or RDI). Some patients have a mild variant of sleep apnea in which they do not become overtly apneic, but they snore, snort, and have many arousals, resulting in excessive daytime sleepiness. This condition has been called the upper airway resistance syndrome.
TREATMENT Indications All patients with an RDI >30 should undergo treatment. Patients with an RDI of 5 to 30 should be treated if the patient has symptomatic daytime sleepiness, neuropsychiatric symptoms, or cardiovascular diseases, such as hypertension, ischemic heart disease, or stroke.
42
clinical CORNERSTONE
l
Weight loss
0 Oral appliance
l
Alcohol
0 Surgery
l
Continuous
avoidance positive airway pressure
@ Monitoring
1 SLEEP DISORDERS
- Vol. 2 No. 5
of blood pressure
roidism is the sole cause of the apnea, then the apnea may resolve. The primary care physician should be familiar with the local laws pertaining to driving and sleep disorders. Regulations vary, but in some states, patients with sleep apnea are reportable to
General Measures The treatments available for obstructive sleep apnea are summarized in Table IV. Because the vast majority of patients are overweight, an aggressive weight-loss program is indicated. The patient’s weight does not have to decrease to the normal range for an improvement in apnea to occur. Although weight loss can lead to cure, unfortunately, it is seldom permanent in these patients. Alcohol has been shown to worsen sleep apnea, and therefore patients should avoid it. When patients use alcohol during the day, they may become much sleepier at night than normal; this phenomenon reduces the tone of the upper airway muscles and makes apneic episodes more severe. Many patients with sleep apnea have arterial hypertension. When the apnea is untreated the hypertension may be difficult to control. Once the apnea is under control, then the requirements for antihypertensive medications may change. In some
licensing authorities. Patients should be cautioned against operating a motor vehicle until they receive treatment, and this advice should be documented in their charts.
Treatment of Specific Anatomical Abnormalities If the patient has an upper airway lesion (eg, nasal obstruction or enlarged tonsils and adenoids), specific surgical therapy may be indicated and patients should be evaluated by an ear, nose, and throat surgeon. In selected sleep apnea patients, such as those who have retrognathia, and mild to moderate apnea, and are not morbidly obese, treatment with an oral appliance alone may be helpful.
patients antihypertensives may not be required at all, whereas others may require modification of their medicine. Thus, blood pressure should be monitored at least weekly during the first month of treatment for apnea, and modifications should be made to blood pressure treatment if required. If hypothyroidism is confirmed in a patient with sleep apnea, the hypothyroid state must be treated, and the patient should also receive treatment with continuous positive airway pressure (CPAP) for at least a few weeks. If the hypothy-
Continuous Positive Airway Pressure The treatment of choice for most patients is CPAP, a device that increases the pressure in the upper airway, stenting it open. The optimal pressure is determined by titration during sleep evaluation. The patient is connected to the CPAP device by a hose connected to a mask that covers the nose or, more rarely, the entire face. Patients should use the CPAP device every time they sleep. Many patients
43
clinical
CORNERSTONE
-
SLEEP
DISORDERS
n
Vol.
2
No. 5
note an improvement in their daytime sleepiness after only 1 night of nasal CPAP, whereas others require up to 2 weeks to note an optimal effect.
Uvulopharyngopalatoplasty, using traditional or laser techniques, has been employed in patients with obstructive sleep apnea. It is difficult to predict which patients will benefit from this type of surgery, and thus I do not recommend it as firstline treatment. Specific surgical procedures (eg, mandibular maxillary surgery) should be attempted only after an expert in this type of surgery has evaluated the patient and recommended its use.
Sleep apnea runs in families, and the clinician should try to determine whether the patient’s children are snoring, are sleepy, or have abnormalities of the jaw like retrognathia. These children can sometimes be treated with orthodontics, which may spare them significant sleep apnea later in life. If patients are still sleepy after appropriate treatment of sleep apnea, they may require further assessment by a sleep disorder specialist. These patients may have a movement disorder and/or narcolepsy. The vast majority of patients with sleep apnea, however, respond well to treatment, but the disorder is chronic and requires long-term or lifelong treatment for best outcome.
OUTCOME
SUGGESTED
Surgery
:
Most patients with sleep apnea will improve after treatment. If the major causative factor is obesity and the patient does not lose weight, then treatment with nasal CPAP may be lifelong. Several aspects of the ongoing care of patients with sleep apnea will require the attention of the primary care clinician. The most common unwanted effects of nasal CPAP are nasal congestion and stuffiness, discomfort related to the nasal mask and the associated head gear, and intolerance of the pressure. In some patients, the nasal obstruction may be associated with nasal discharge. Many patients with these nasal symptoms can be helped with the use of a humidification system added to the CPAP system. If the cause of the obstruction is increased exposure to allergen, then the allergic rhinitis might be treated with topical intranasal steroids. Nasal streaming may improve with the use of ipratropium nasal spray. It is my experience that patients with mild obstructive sleep apnea are much more likely to have difficulty tolerating the nasal CPAP. If a patient has a large weight gain, then the pressure of the CPAP device may have to be modified upward. Likewise, if the patient has a large weight loss, the pressure of the CPAP device may have to be decreased. If a patient’s weight falls into the normal range, CPAP may no longer be required.
READING
American Academy of Sleep Medicine Task Force. Sleep-related breathing disorders in adults: recommendations for syndrome definition and measurement techniques in clinical research. The Report of an American Academy of Sleep Medicine Task Force. Sleep. 1999; 22:667-689. American Sleep Disorders Association. Practice parameters for the indications for polysomnography and related procedures. Polysomnography Task Force, American Sleep Disorders Association Standards of Practice Committee. Sleep. 1997;20:406&422. Bahammam A, Kryger M. Decision making in obstructive sleep-disordered breathing. Putting it all together. Clin Chest Med. 1998;19:87-97. Exar EN, Collop NA. The upper airway resistance syndrome. Chest. 1999;115:1127-1139. Kryger MH. Management of obstructive sleep apneahypopnea syndrome: an overview. In: Kryger MH, Roth T, Dement WC, eds. Principles and Practice of Sleep Medicine. Philadelphia, Pa: WB Saunders Co. 2000. Loube DI, Gay PC, Strohl KP, et al. Indications for positive airway-pressure treatment of adult obstructive sleep apnea patients: a consensus statement. Chest. 1999;115: 863-866. Loube DI. Technologic advances in the treatment of obstructive sleep apnea syndrome. Chest. 1999; 116: 1426-1433. Skomro RP, Kryger MH. Clinical presentations of obstructive sleep apnea syndrome. Prog Cardiovasc Dis. 1999;41:331-340. Stroll0 PJ Jr, Rogers RM. Obstructive sleep apnea. N Engl J Med. 1996;334:99-104.
44
9 SLEEP DISORDERS
- Vol. 2 No. 5
Diagnosis and Management of Sleep Apnea Syndrome Meir
H. Kryger,
MD,
FRCPC
Professor of Medicine University of Manitoba Winnipeg, Manitoba Canada
Sleep apnea is the cessation of breathing during sleep. These episodes result in hypoxemia and sleep disruption;.. thus the consequences are both cardiorespiratory and neural. Sleep apnea syndrome is defined by a constellation of signs and symptoms, with the main presenting symptom being excessive daytime sleepiness. A diagnosis requires documentation of episodes of abnormal breathing during sleep. This disorder, once thought to be very rare, is so common that it is unlikely that any busy clinician has not encountered a case. Facilities for the evaluation of sleep breathing disorders are now available in most communities. With the introduction of continuous positive airway pressure and other treatments, most patients have complete resolution of their disabling symptoms.
PATHOPHYSIOLOGY
may have a respiratory control system that is overly sensitive, which overshoots and undershoots, and thus excessive breathing (hyperpnea) alternates with episodes of hypoventilation or cessation of
Repetitive episodes of cessation of breathing can be caused by a reduction of neural impulses from the central nervous system to the muscles of respiration or by upper airway obstruction that manifests during sleep. The former results in central sleep apnea, whereas the latter results in obstructive sleep apneakypopnea syndrome, and it is encountered much more frequently in clinical practice.
Central Sleep Apnea Decreased neural impulses from the central nervous system to the muscles of respiration generally reflect either structural or physiologic abnormalities in the respiratory control system. Structural lesions in the brain stem, the site of the respiratory pacemakers, are an example of disorders that result in blunted control of breathing, causing repetitive episodes of central apnea. For many types of central apnea-for example, congenital hypoventilation syndromes-the cause of the blunting of the drive to breathe is unknown. Paradoxically, patients who have an increased drive to breathe
breathing (hypopnea or apnea). This type of abnormality has been documented in patients with Cheyne-Stokes breathing caused by heart failure and those living at high altitudes. Such patients are much more likely to present with insomnia than are patients with obstructive apnea, who usually complain about excessive daytime sleepiness.
Obstructive Sleep Apnea Obstructive sleep apnea, the more common type of apnea, is caused by obstruction in the upper airway.
39
clinical CORNERSTONE
.
SLEEP DISORDERS
.
Vol.2 No. 5
Daytime
Nighttime
Sleepiness
Snoring
Impaired concentration
Observed apnea
Irritability
Choking
Depression symptoms
Sweating
Decreased libido
Nocturia
In the vast majority
of patients,
the obstruction
EPIDEMIOLOGY Obstructive sleep apnea was once thought to be extremely rare. We now know that it is a quite common condition affecting approximately 4% of adult men and 2% of adult women. Obstructive sleep apnea runs in families, and it affects all agegroups. In adults this disorder commonly occurs in males, the morbidly obese, and persons with cardiovascular disease, for example, arterial hypertension. In children, enlarged tonsils or adenoids can cause obstructive sleep apnea. Central sleep apnea is much less common. For the remainder of this review I will focus on obstructive sleep apnea.
is
related to obesity, which decreases the size of the pharyngeal airway, or..by anatomical lesions in the upper airway, for example, retrognathia or enlarged tonsils. CONSEQUENCES Apnea, whether central or obstructive, results in hypoventilation (which leads to hypoxemia), changes in autonomic nervous system tone (which can lead to bradycardia and other arrhythmias during sleep), and systemic hypertension. To start breathing again, most patients awaken briefly,
CLINICAL PRESENTATION Including a family member or bed partner in the interview with the patient can be extremely valuable. Indeed, very often the evaluation of the patient may have started because such a person witnessed the patient’s distressing symptoms, including breathing interruptions. The snoring of the patient may even interfere with the bed partner’s ability to sleep. Obstructive sleep apnea can affect so many different systems that patients may present with problems that, at first glance, do not appear to be related to obstructive sleep apnea. Table I outlines the symptoms that may indicate obstructive sleep apnea. Unless the clinician incorporates a sleep history into the routine clinical evaluation, the disorder will be missed in many patients.
which reestablishes ventilation. These patients have hundreds of arousals each night, resulting in repetitive cardiorespiratory changes during sleep or unstable fragmented sleep. These 2 consequences result in the clinical features at presentation, such as neural symptoms like daytime sleepiness. The cardiorespiratory changes result in an increased risk of arterial hypertension, coronary artery disease, and stroke. The most severely affected patients may develop respiratory failure (both asleep and awake) and car pulmonale (heart failure caused by respiratory failure). The most severely affected patients are said to have pickwickian syndrome, also called obesity hypoventilation syndrome.
Daytime Symptoms By far the most common presentation of patients with sleep apnea is excessive daytime sleepiness.
40
clinicnl CORNERSTONE
l
Enlarged tonsils and adenoids
o Increased neck collar size (243 cm or 17 in)
l
Nasal obstruction
0 Retrognathia
0 Peripheral edema
l
Obesity
l
Macroglossia
l
Sleep apnea
0 Insufficient l
and overjet
sleep
Unwanted effects of drugs
These patients fall asleep at the wrong time and the wrong place. They fall asleep at the movies, in front of the television, and sometimes even at work or behind the wheel of a motor vehicle. They often will have poor memory or difficulty concentrating, and they may demonstrate poor performance at work or school. The patient or family member may relate that the problem has caused moodiness
l
Hypothyroidism
l
Narcolepsy/cataplexy
l
Movement
= SLEEP DISORDERS
a Vol. 2 No. 5
disorders
with quieter or silent periods when the patient is obviously not breathing. Waking up with headache, choking, nocturia, and diaphoresis are other, less common, symptoms.
PHYSICAL
EXAMINATION
The vast majority of patients with obstructive sleep apnea are obese or have an upper airway compromised by an abnormality of the jaw (micrognathia or retrognathia). Younger patients may have enlarged tonsils. In some patients an overjet can be confirmed on examination, whereas for others the reason for airway obstrnction is not entirely clear on physical examination. These patients must have the entire upper airway, including the nose, examined. Some patients may require evaluation by an ear, nose, and throat specialist. In the most severely affected patients there will be evidence of right heart failure. Findings on physical examination are summarized in Table II.
and irritability, and they may indicate that the abnormal mood and sleepiness of the patient have resulted in family strife. Patients are often diagnosed with depression. Decreased libido is also a common symptom. The most severely affected individuals may develop respiratory failure or right heart failure and may present with peripheral edema and polycythemia.
DIFFERENTIAL
DIAGNOSIS
Several other conditions can result in excessive daytime sleepiness (Table III). Hypothyroidism has some symptoms that overlap with those of sleep apnea and may actually cause sleep apnea. Approximately 2% to 3% of apnea patients will be found to have hypothyroidism. Cataplexy, the sudden loss of muscle tone with emotion, is found in narcolepsy but not in obstructive sleep apnea. Hypnagogic hallucinations, dream-like visual or
Nighttime Symptoms Some patients present because a bed partner or family member has observed them snoring loudly and ceasing to breathe during sleep. The snoring has a distressing quality, with loud snoring alternating
41
clinical CORNERSTONE
1 SLEEP DISORDERS
1 Vol. 2 No. 5
INTEGRATING LABORATORY
auditory hallucinations occurring at sleep onset, which are common in narcolepsy, can also occur in some persons with obstructive sleep apnea. Many patients with narcolepsy feel refreshed after a short nap, whereas those with obstructive sleep apnea usually do not. Movement disorders, such as periodic movements in sleep, can lead to insomnia and excessive daytime sleepiness. Movement disorders are discussed elsewhere in this issue in the article by Dr. Mahowald.
DIAGNOSTIC
CLINICALAND DATA
Sleep apnea syndrome is present when clinical features combine with more than 5 abnormal breathing events per hour of sleep. The severity of apnea is determined by grading the severity of the key symptom (daytime sleepiness) and the severity of the RDI (see previous text).
TESTS
If a patient is suspected of having obstructive sleep apnea, then documentation of the disorder is required. In general, this means that the patient will have to undergo an overnight sleep study that monitors cardiorespiratory and electroencephalographic variables, and documents periodic movements in sleep, such as activity of the legs. The technology for gathering these data is changing rapidly, and computerized systems are being used more and more often. An overnight sleep study can answer the following questions: How often does the patient have obstructed breathing events per hour of sleep? These abnormal breathing events could be apneas, hypopneas, or increased efforts to breathe (for example, snorts). The results of the testing are expressed as the respiratory disturbance index (RDI), and it includes apneas, hypopneas, and arousals related to respiratory effort per hour of sleep. What is the patient’s sleep structure? The number of arousals per hour of sleep and the sleep architecture (distribution of sleep stages) are also usually determined in an overnight sleep study. Patients with sleep apnea have fragmented sleep with many arousals. They usually show a reduction in the amount of slow-wave sleep and frequently show a reduction in rapid-eye-movement sleep. What is the nature of the patient’s movements during sleep? The movement index is derived from the number of contractions per hour of the anterior tibialis muscle. Many patients with obstructive sleep apnea also have periodic movements in sleep, an extremely common condition. This topic is discussed more thoroughly elsewhere in this issue in the article by Dr. Roth.
Severity of Sleepiness Sleepiness may be considered mild when it is present during activities requiring little attention (eg, watching television), moderate during activities requiring some attention (eg, business meetings), or severe during activities requiring active attention (eg, operating a motor vehicle).
Severity of the Sleep Breathing Disorder Sleep obstructive events are considered mild when the RDI falls between 5 and 15, moderate is between 15 and 30, and severe is in excess of 30 per hour. The overall severity of the syndrome is the more severe of the 2 (sleepiness or RDI). Some patients have a mild variant of sleep apnea in which they do not become overtly apneic, but they snore, snort, and have many arousals, resulting in excessive daytime sleepiness. This condition has been called the upper airway resistance syndrome.
TREATMENT Indications All patients with an RDI >30 should undergo treatment. Patients with an RDI of 5 to 30 should be treated if the patient has symptomatic daytime sleepiness, neuropsychiatric symptoms, or cardiovascular diseases, such as hypertension, ischemic heart disease, or stroke.
42
clinical CORNERSTONE
l
Weight loss
0 Oral appliance
l
Alcohol
0 Surgery
l
Continuous
avoidance positive airway pressure
@ Monitoring
1 SLEEP DISORDERS
- Vol. 2 No. 5
of blood pressure
roidism is the sole cause of the apnea, then the apnea may resolve. The primary care physician should be familiar with the local laws pertaining to driving and sleep disorders. Regulations vary, but in some states, patients with sleep apnea are reportable to
General Measures The treatments available for obstructive sleep apnea are summarized in Table IV. Because the vast majority of patients are overweight, an aggressive weight-loss program is indicated. The patient’s weight does not have to decrease to the normal range for an improvement in apnea to occur. Although weight loss can lead to cure, unfortunately, it is seldom permanent in these patients. Alcohol has been shown to worsen sleep apnea, and therefore patients should avoid it. When patients use alcohol during the day, they may become much sleepier at night than normal; this phenomenon reduces the tone of the upper airway muscles and makes apneic episodes more severe. Many patients with sleep apnea have arterial hypertension. When the apnea is untreated the hypertension may be difficult to control. Once the apnea is under control, then the requirements for antihypertensive medications may change. In some
licensing authorities. Patients should be cautioned against operating a motor vehicle until they receive treatment, and this advice should be documented in their charts.
Treatment of Specific Anatomical Abnormalities If the patient has an upper airway lesion (eg, nasal obstruction or enlarged tonsils and adenoids), specific surgical therapy may be indicated and patients should be evaluated by an ear, nose, and throat surgeon. In selected sleep apnea patients, such as those who have retrognathia, and mild to moderate apnea, and are not morbidly obese, treatment with an oral appliance alone may be helpful.
patients antihypertensives may not be required at all, whereas others may require modification of their medicine. Thus, blood pressure should be monitored at least weekly during the first month of treatment for apnea, and modifications should be made to blood pressure treatment if required. If hypothyroidism is confirmed in a patient with sleep apnea, the hypothyroid state must be treated, and the patient should also receive treatment with continuous positive airway pressure (CPAP) for at least a few weeks. If the hypothy-
Continuous Positive Airway Pressure The treatment of choice for most patients is CPAP, a device that increases the pressure in the upper airway, stenting it open. The optimal pressure is determined by titration during sleep evaluation. The patient is connected to the CPAP device by a hose connected to a mask that covers the nose or, more rarely, the entire face. Patients should use the CPAP device every time they sleep. Many patients
43
clinical
CORNERSTONE
-
SLEEP
DISORDERS
n
Vol.
2
No. 5
note an improvement in their daytime sleepiness after only 1 night of nasal CPAP, whereas others require up to 2 weeks to note an optimal effect.
Uvulopharyngopalatoplasty, using traditional or laser techniques, has been employed in patients with obstructive sleep apnea. It is difficult to predict which patients will benefit from this type of surgery, and thus I do not recommend it as firstline treatment. Specific surgical procedures (eg, mandibular maxillary surgery) should be attempted only after an expert in this type of surgery has evaluated the patient and recommended its use.
Sleep apnea runs in families, and the clinician should try to determine whether the patient’s children are snoring, are sleepy, or have abnormalities of the jaw like retrognathia. These children can sometimes be treated with orthodontics, which may spare them significant sleep apnea later in life. If patients are still sleepy after appropriate treatment of sleep apnea, they may require further assessment by a sleep disorder specialist. These patients may have a movement disorder and/or narcolepsy. The vast majority of patients with sleep apnea, however, respond well to treatment, but the disorder is chronic and requires long-term or lifelong treatment for best outcome.
OUTCOME
SUGGESTED
Surgery
:
Most patients with sleep apnea will improve after treatment. If the major causative factor is obesity and the patient does not lose weight, then treatment with nasal CPAP may be lifelong. Several aspects of the ongoing care of patients with sleep apnea will require the attention of the primary care clinician. The most common unwanted effects of nasal CPAP are nasal congestion and stuffiness, discomfort related to the nasal mask and the associated head gear, and intolerance of the pressure. In some patients, the nasal obstruction may be associated with nasal discharge. Many patients with these nasal symptoms can be helped with the use of a humidification system added to the CPAP system. If the cause of the obstruction is increased exposure to allergen, then the allergic rhinitis might be treated with topical intranasal steroids. Nasal streaming may improve with the use of ipratropium nasal spray. It is my experience that patients with mild obstructive sleep apnea are much more likely to have difficulty tolerating the nasal CPAP. If a patient has a large weight gain, then the pressure of the CPAP device may have to be modified upward. Likewise, if the patient has a large weight loss, the pressure of the CPAP device may have to be decreased. If a patient’s weight falls into the normal range, CPAP may no longer be required.
READING
American Academy of Sleep Medicine Task Force. Sleep-related breathing disorders in adults: recommendations for syndrome definition and measurement techniques in clinical research. The Report of an American Academy of Sleep Medicine Task Force. Sleep. 1999; 22:667-689. American Sleep Disorders Association. Practice parameters for the indications for polysomnography and related procedures. Polysomnography Task Force, American Sleep Disorders Association Standards of Practice Committee. Sleep. 1997;20:406&422. Bahammam A, Kryger M. Decision making in obstructive sleep-disordered breathing. Putting it all together. Clin Chest Med. 1998;19:87-97. Exar EN, Collop NA. The upper airway resistance syndrome. Chest. 1999;115:1127-1139. Kryger MH. Management of obstructive sleep apneahypopnea syndrome: an overview. In: Kryger MH, Roth T, Dement WC, eds. Principles and Practice of Sleep Medicine. Philadelphia, Pa: WB Saunders Co. 2000. Loube DI, Gay PC, Strohl KP, et al. Indications for positive airway-pressure treatment of adult obstructive sleep apnea patients: a consensus statement. Chest. 1999;115: 863-866. Loube DI. Technologic advances in the treatment of obstructive sleep apnea syndrome. Chest. 1999; 116: 1426-1433. Skomro RP, Kryger MH. Clinical presentations of obstructive sleep apnea syndrome. Prog Cardiovasc Dis. 1999;41:331-340. Stroll0 PJ Jr, Rogers RM. Obstructive sleep apnea. N Engl J Med. 1996;334:99-104.
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