Tonya Russell
Obstructive Sleep Apnea
GENERAL PRINCIPLES
Definition
· Obstructive sleep apnea (OSA) is a condition in which there is cessation or decreased airflow during sleep due to upper airway narrowing or obstruction despite ongoing respiratory effort.
· Apneas are complete cessation of airflow.
· Hypopneas are diminished airflow (<70% of baseline) associated with a 4% oxygen desaturation.
· Respiratory effort–related arousals (RERAs) are a change in airflow that does not meet criteria for apnea or hypopnea, but are associated with an arousal.
· All respiratory events (e.g., apneas and hypopneas) must last at least 10 seconds.
· The apnea-hypopnea index (AHI) represents the number of apneas and hypopneas per hour of sleep.
· The respiratory disturbance index (RDI) represents the number of apneas, hypopneas, and RERAs per hour of sleep.
Classification
· An AHI of <5 in adults is normal.
· An AHI of 5 to 14 in adults is mild sleep apnea.
· An AHI of 15 to 29 in adults is moderate sleep apnea.
· An AHI of >30 in adults is severe sleep apnea.
Epidemiology
· The prevalence of OSA, as defined by an AHI >5 events per hour, is estimated to be 24% of men and 9% of women.
· The prevalence of obstructive sleep apnea-hypopnea syndrome (OSAHS), as defined by an AHI >5 in association with daytime sleepiness, is 4% of men and 2% of women.1
Pathophysiology
· Obstructive apneas and hypopneas result from excessive soft tissue or structural abnormalities of the upper airway resulting in cessation of breathing (apneas) or decreased airflow (hypopneas) during sleep.
· Obstructive events can be associated with snoring, arousals from sleep, and oxygen desaturations.
Risk Factors
· Risk factors for OSA include obesity, enlarged tonsils, macroglossia, and craniofacial abnormalities.
· Use of sedatives, narcotics, or alcohol can also increase the risk for OSA.
· Medical conditions that can contribute to decreased muscle tone, weight gain, or craniofacial abnormalities such as hypothyroidism or acromegaly can also increase the risk of OSA.
Prevention
· Weight loss may help to prevent OSA.
· Avoidance of sedatives, narcotics, and alcohol can be of benefit.
· Treatment of underlying medical conditions that may be contributing to OSA is of benefit.
Associated Conditions
· Patients with OSA are more likely to be hypersomnolent.
· Patients with OSA have an increased risk of motor vehicle collisions.2,3
· OSAHS increases the risk for hypertension, with the risk increasing as the severity of OSA increases.4,5 Treatment of OSA can improve the control of hypertension, but it may take several weeks before the effects are seen.6–9
· Patients with severe untreated OSA (AHI >30) have a higher risk of fatal and nonfatal cardiovascular events when compared with healthy controls and patients with severe OSAHS treated with continuous positive airway pressure (CPAP).10 There was no difference in other cardiovascular risk factors between the untreated and the CPAP-treated severe OSAHS groups.
· There is increased risk of congestive heart failure in patients with OSA.11
· OSA is associated with an adjusted hazard ratio of 1.97 for risk of stroke or death from any cause.12
· Studies have demonstrated impaired glucose tolerance and increased insulin resistance in patients with OSA even when controlled for obesity.13,14 Treatment of OSA with CPAP has been shown to improve glycemic control.15
DIAGNOSIS
Clinical Presentation
History
· Common complaints for patients with OSA include daytime sleepiness (including falling asleep while driving), not feeling refreshed upon awakening, awakening snorting or gasping, and poor concentration. Patients may report headaches upon awakening.
· The patient’s bed partner may report witnessing apneic events. In addition, the bed partner may report disruption of his or her sleep due to the patient’s loud snoring.
Physical Examination
· The physical exam should note the patient’s weight and body mass index.
· Neck circumference should be measured. Neck circumference >17 inches in men and >16 inches in women is associated with increased risk of OSA.
· Inspection of the oropharynx should be performed to assess Mallampati class and for macroglossia and enlarged tonsils.
Diagnostic Criteria
Sleep apnea is diagnosed when the AHI is >5 on either an in-lab polysomnogram or at-home unattended (no technician) ambulatory study.
Differential Diagnosis
· Central sleep apnea is a different type of sleep-disordered breathing in which there is cessation of airflow and no respiratory effort.
· Other causes of daytime sleepiness such as restless legs syndrome (RLS), periodic limb movements, sleep deprivation, narcolepsy, or idiopathic hypersomnia should be considered.
Diagnostic Testing
· The gold standard for diagnosing OSA is with an in-lab overnight polysomnogram.
o Typically, the monitoring includes electroencephalogram, electrooculogram, and electromyogram leads for sleep staging.
o In addition, respiratory effort is monitored by thoracic and abdominal belts, as well as airflow via thermistor and pressure transducer.
o Electrocardiogram and oxygen saturations are recorded, and in situations in which hypoventilation is a concern, transcutaneous carbon dioxide levels may be monitored.
o In-lab polysomnogram studies are often performed as split studies. Per the American Academy of Sleep Medicine recommendations, if a patient has an AHI >40 events per hour during the first 2 hours of sleep, a CPAP titration can be started during the same study.16
· Portable polysomnographic monitoring devices can be used to diagnose OSA.
o Portable devices typically monitor airflow, respiratory effort, pulse oximetry, and snoring. However, data regarding body position and sleep state are often not obtained.
o If a portable study is negative and there is still a clinical suspicion for OSA, an in-lab polysomnogram should be pursued.
o Portable devices should not be used in patients in whom there is concern for other sleep-related conditions such as obesity hypoventilation syndrome, central sleep apnea, narcolepsy, or periodic limb movements. In addition, they should not be used in patients with severe cardiac or pulmonary disease.
TREATMENT
Medications
· Modafinil is a stimulant medication approved for use in patients with continued daytime sleepiness despite adequate therapy of OSAHS with CPAP and no other obvious cause for sleepiness.17
· Weight reduction should be encouraged in obese patients.
· Treatment of underlying endocrine disorders, such as hypothyroidism and acromegaly, should be pursued.
Other Nonpharmacologic Therapies
· CPAP is the standard therapy for OSA. It is typically initiated for home use after a CPAP titration has been performed in a sleep center. During titrations, CPAP is increased to relieve snoring as well as obstructive apneas and hypopneas.
· Autotitrating positive airway pressure (APAP) devices are available. These machines titrate through a range of pressures on the basis of algorithms within the device to determine snoring and changes in airflow. Several studies have shown that APAP is as effective as CPAP in treating OSA.
o In patients who require a wide range of pressures to resolve their OSA and have trouble tolerating higher pressures during the entire night (e.g., a patient who requires lower pressures in the lateral position or during non–rapid eye movement sleep and higher pressures in the supine position or during rapid eye movement sleep), APAP may be a more tolerable option.
o APAP is not a good option for patients with significant comorbid conditions.18
· Patients who have difficulty tolerating CPAP may prefer bilevel positive airway pressure devices.
· Potential side effects and barriers to use of CPAP, as well as potential remedies, are outlined in Table 18-1.
· Oral appliances can be used to treat OSA. Overall, the success rate is approximately 50%, although patients with more severe OSA are less likely to respond.
o Complications from oral appliances include temporomandibular joint pain, tooth and gum irritation, and occlusal changes, although most complications are temporary.
o Oral appliances should be fitted by practitioners specializing in dental sleep medicine.
o Patients being considered for oral appliances for snoring or OSA should undergo evaluation with overnight polysomnogram before starting therapy. If OSA is present on the baseline study, a repeat polysomnogram should be performed with the appliance in place to document resolution of the OSA.19
· Nasal expiratory positive airway pressure devices are small resistance valves that insert into the nostrils. The resistance generated by exhaling through the valve creates a positive pressure in the upper airway. These devices are best used in patients with milder OSA or those who cannot tolerate CPAP. A polysomnogram should be performed with the devices in place to ensure the adequacy of therapy.
TABLE 18-1 Complications Related to CPAP and Potential Remedies
APAP, autotitrating positive airway pressure; CPAP, continuous positive airway pressure.
Surgical Management
· Patients who want to consider surgery for OSA should be evaluated by an otolaryngologist to determine whether the area of upper airway obstruction is amenable to surgery.
· Tracheotomy can be curative for OSA, as the area of upper airway obstruction is bypassed.
· Uvulopalatopharyngoplasty is a common surgery performed for OSA. Response to surgery varies from 40% to 60% depending upon how surgical success is defined. Patients with higher AHIs are less likely to respond. Complications can include voice changes, foreign body sensation, and nasal reflux.20
· Laser-assisted uvulopalatoplasty differs from uvulopalatopharyngoplasty in that the tonsils and pharyngeal pillars are not excised. Currently, the recommendations for use of laser-assisted uvulopalatoplasty are only in primary snoring, not OSA.21
· Patients being considered for surgical treatment for snoring or OSA should undergo evaluation with overnight polysomnogram prior to surgery. If OSA is present on the baseline study, a postsurgical polysomnogram should be performed to document resolution of the OSA.22
· OSA may improve with weight loss following bariatric surgery.
Lifestyle/Risk Modification
· Weight loss should be encouraged.
· Patients should limit alcohol, sedatives, and narcotics.
· Driving precautions should be discussed with patients.
Insomnia
GENERAL PRINCIPLES
· Insomnia is the inability to initiate or maintain sleep.
· While approximately one-third of the general population has experienced insomnia at some point, of those patients with severe insomnia, approximately 80% have reported symptoms for more than a year.23
· See Table 18-2 for causes of insomnia and associated characteristics.
· Risk factors for insomnia depend upon the underlying cause, but can include depression, anxiety, acute life stressors, stimulant use, withdrawal from sedating drugs, or poor sleep hygiene.
· Following good sleep hygiene techniques can prevent insomnia. Good sleep hygiene consists of activities such as maintaining a regular sleep schedule, avoiding stimulants (caffeine and nicotine) close to bedtime, and avoiding reading or watching TV in bed. Treatment of conditions such as depression and anxiety may also help to prevent insomnia.
· Insomnia may be triggered by depression and anxiety. However, insomnia may also worsen depression and anxiety.
· Patients with insomnia may exhibit increased irritability, difficulty concentrating, and complaints of somatic pain.
TABLE 18-2 Causes of Insomnia and Associated Characteristics
DIAGNOSIS
Clinical Presentation
· Patients report difficulty with initiating and/or maintaining sleep.
· Patients may report racing thoughts that prevent them from sleeping.
· Often, patients are fatigued, but not overtly sleepy during the day.
· Elicit any history of use of medications or drugs that can contribute to insomnia or confounding medical conditions such as chronic pain, RLS, depression, or anxiety.
· In addition, the history should be directed to evaluate the patient’s sleep schedule and to assess for poor sleep hygiene.
· There are no specific physical exam findings for insomnia.
Diagnostic Criteria
· In general, a patient should complain of difficulty initiating and/or maintaining sleep that is associated with perceived limitation in daytime functioning such as fatigue, poor concentration, or irritability. There should be adequate opportunity for sleep.
· More specific criteria depend upon the cause of the insomnia.
Differential Diagnosis
Patients with paradoxical insomnia or sleep state misperception feel they suffer from insomnia. However, objective testing such as polysomnogram or actigraphy demonstrates normal sleep time and pattern. Often, their daytime impairment is less severe than patients with insomnia.
Diagnostic Testing
· If there is clinical concern, a polysomnogram can be performed to rule out other causes of poor sleep maintenance, such as periodic limb movements or sleep-disordered breathing.
· Actigraphy can be used to confirm reported sleep patterns and sleep times.
· Urine drug screen can be used to screen for use of illicit drugs that may trigger insomnia.
TREATMENT
Medications
· Over-the-counter medications are frequently used by patients to treat insomnia. Table 18-3 lists common over-the-counter medications and their potential side effects. There are no strong data to support the efficacy of these agents.24
· The prescription medications that are approved for treatment of insomnia are the benzodiazepine receptor agonists and the melatonin receptor agonists. Of these, eszopiclone (nonbenzodiazepine hypnotic) and ramelteon (melatonin agonist) are the only ones FDA approved for long-term use. The benzodiazepine receptor agonists are considered controlled substances, whereas the melatonin receptor agonists are not.24
· Frequently, sedating antidepressants are also prescribed for insomnia in off-label use, although data supporting their use are lacking. Table 18-4 outlines the prescription medications for insomnia as well as some of the potential side effects.24
· Treatment of underlying medical or psychiatric conditions potentially contributing to insomnia should be instituted.
TABLE 18-3 Over-the-Counter Medications for Insomnia and Their Side Effects
TABLE 18-4 Prescription Medications Used for Insomnia
Other Nonpharmacologic Therapies
· Cognitive-behavioral therapy (CBT) encompasses a wide variety of techniques aimed at breaking the cycle of insomnia.25 Table 18-5 describes various components of CBT for insomnia.
· CBT has been shown to be beneficial in improving the nighttime and daytime symptoms associated with insomnia.26–28
TABLE 18-5 Components of Cognitive-Behavioral Therapy for Insomnia
Lifestyle/Risk Modification
· Patients should be encouraged to keep a regular sleep schedule with a consistent bedtime and waking time.
· Patients should avoid the use of stimulants such as caffeine and nicotine.
· Patients should modify their sleeping environment to minimize environmental disturbances.
· Patients should avoid activities such as watching TV or reading in bed.
Restless Legs Syndrome
GENERAL PRINCIPLES
· RLS consists of an uncomfortable sensation in the extremities (most commonly the legs), which is worse in the evening and nighttime, but can occur during the day in sedentary situations, and is temporarily relieved by movement.
· Prevalence of RLS is estimated to be between 2.5% and 15% of the population. In some patients with RLS, there is a hereditary link.29
· The severity of symptoms can be highly variable.
· The role of dopamine in RLS has been most strongly supported by the improvement of symptoms with dopamine agonists.30
· Iron is necessary for the rate-limiting step in dopamine synthesis. Therefore, low iron levels may decrease dopamine synthesis.31 Ferritin levels <50 μg/L have been associated with increased severity of RLS. Iron supplementation is recommended in the setting of RLS when ferritin is <50 μg/L.32
· RLS can be associated with other underlying conditions such as pregnancy, uremia, and anemia.
· Pharmacologic agents such as caffeine, nicotine, alcohol, dopamine antagonists, diphenhydramine, serotonin reuptake inhibitors, and tricyclic antidepressants may worsen RLS.33 Avoiding pharmacologic agents associated with RLS may help prevent symptoms.
DIAGNOSIS
Clinical Presentation
· Patients will report an uncomfortable sensation in the legs, which can sometimes involve the arms. Typically, the sensation is bilateral. If a patient reports mainly unilateral symptoms, consideration should be given to the possibility of a spinal cord lesion.
· The sensations should have a circadian rhythm to them in that they are worse in the late evening and earlier part of the night. However, some patients experience symptoms during the day when in prolonged sedentary situations.
· The sensations are typically temporarily relieved by movement, but return upon cessation of the movement.
· There are no specific physical exam findings for RLS.
Diagnostic Criteria
· RLS is a clinical diagnosis in which the four essential criteria, as outlined in Table 18-6, are met.34
· Periodic limb movements are frequently seen on the polysomnograms of patients with RLS, although a polysomnogram is not required to make the diagnosis of RLS.
· RLS is a clinical diagnosis. However, a polysomnogram can be performed if the presence of periodic limb movements would change therapy.
· A ferritin should be checked to evaluate if iron supplementation may be beneficial.
TABLE 18-6 Clinical Criteria for Restless Legs Syndrome
Data from Allen RP, Picchietti D, Hening WA, et al. Restless legs syndrome: diagnostic criteria, special considerations, and epidemiology. A report from the restless legs syndrome diagnosis and epidemiology workshop at the National Institutes of Health. Sleep Med 2003;4:101–119.
Differential Diagnosis
Musculoskeletal pain, neuropathy, leg cramps, and sleep starts are in the differential diagnosis for RLS.
TREATMENT
· An oral iron supplement can be prescribed if the ferritin is <50 ng/mL.
· Dopamine agonists (pramipexole and ropinirole) are the initial therapy in patients with RLS that require treatment and have a normal ferritin. These medications should be initiated at the lowest dose and titrated every 5 to 7 days until relief of symptoms or maximal dose is reached.33
· Gabapentin at a starting dose of 600 mg and titrated up to 2,400 mg as needed can also be used to treat RLS symptoms without significant side effects.35
· Benzodiazepines and opioids can also be effective in treating RLS symptoms.
· Caffeine should be limited as it can worsen RLS symptoms.
· Avoidance of medications that can trigger RLS (such as serotonin reuptake inhibitors) should be attempted.
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