Workup and indications for polysomnography in patients with sleep

Workup and indications for polysomnography in patients with sleep-related complaints KENNETH S. KNOX, MD BRIAN H. FORESMAN, DO A significant proportion of the population has chronic sleep problems necessitating an increasing involvement by the primary care physician. Also, the general patient population is becoming more familiar with these disorders and is seeking assistance. Because sleep studies are expensive and time consuming, adhering to the recognized indications for testing reduces the number of inappropriate studies. Under most circumstances, individuals with excessive daytime sleepiness and symptoms suggestive of obstructive sleep apnea are candidates for polysomnography. Other individuals with parasomnias or difficult-to-treat insomnia are also candidates for testing. In some circumstances, procedures designed to assess sleepiness may also need to be used to ascertain the impact of the disorder on daytime functioning and may be part of evaluations involving the transportation industry. Only after taking a thorough history and doing a physical examination can the physician make an accurate determination of the appropriate study type. (Key words: polysomnography, sleep disorders, daytime fatigue, sleepiness, insomnia) first recognize that sleepiness and poor sleep are symptoms and not diseases. Although not a disease, sleepiness can have serious ramifications. Excessive sleepiness and the disorders of sleep result in poor performance, impaired functioning, and a subsequent increase in accidents. The seriousness of this problem is best described in recent studies depicting the hazard of driving sleepy to both society and individual health.1,2 Moreover, sleep-disordered breathing directly affects cardiovascular health3 and likely is an independent risk factor for mortality.4 Therefore, by questioning patients about sleepiness and identifying the problem, an appropriate evaluation and treatment regimen can be implemented that has an impact on patient health. How can we as physicians identify the pathologically sleepy patient? This article will focus on how to recognize these patients and when polysomnography is indicated. The problem...the history The prevalence of excessive daytime sleepiness is often quoted as less than 5%, but a more recent study in a population of drivers and other data suggest that it may be much higher.5 One problem with measuring the prevalence is that defining and quantifying sleepiness are difficult. Differentiating sleepiness, fatigue, weakness, and depression is somewhat difficult but may be accomplished using the history and physical examination findings coupled with some selected testing. Several assessments of sleepiness have been developed to address different aspects of the symptom and to help with our understanding of the physiology behind the symptom. The most widely used test is the Multiple Sleep Latency Test (MSLT), which is the current “gold standard” for determining the physiologic level of sleepiness. The MSLT is a timeconsuming study that is performed across the course of a day and should not be used as a screening tool. As such, a good sleep history is essential and is aimed at uncovering common sleep disorders. To objectively measure daytime sleepiness as part of the history and physical I t seems there are never enough hours in the day—or is it night? Today’s pace has individuals spending less time sleeping and more time working and playing. This translates into a common chief complaint in the outpatient setting of daytime fatigue, tiredness, or sleepi- Dr Knox is a visiting assistant professor, Department of Medicine, Division of Pulmonary, Allergy, Critical Care and Occupational Medicine, Indiana University School of Medicine, Indianapolis, Ind. Dr Foresman is a clinical assistant professor, Medical Director, Indiana University Center for Sleep Disorders, Department of Medicine, Division of Pulmonary, Allergy, Critical Care and Occupational Medicine, Indiana University School of Medicine. This project was supported, in part, by the American Osteopathic Association’s Clinical Investigator Development Award. Correspondence to Brian H. Foresman, DO, Indiana University Medical Center, Division of Pulmonary, Critical Care and Occupational Medicine, 550 University Blvd, University Hospital #5450, Indianapolis, IN 76202-5250. E-mail: bforesma@iupui.edu ness. With the growing number of people using the Internet to locate diseasespecific information, it is common that the chief complaint is replaced by a request for testing or empiric therapy. It is easy for physicians in general to sidestep the complaint of fatigue or sleepiness by ordering routine blood tests, prescribing a short course of a sleeping pill, or by blaming the work schedule. After all, isn’t everyone tired these days? Distinguishing “normal sleepiness,” that due to inadequate sleep from sleepiness due to medical disease or underlying sleep disorder can be difficult because sleepiness is the common final symptom that results from disrupted sleep, regardless of cause. The problem arises because treatment modalities may be significantly different, depending on the etiology. The differentiation lies in recognizing dysfunctional patterns of behavior as opposed to symptoms suggestive of underlying disease. In so doing, we must S22 • JAOA • Vol 100 • No 8 • Supplement to August 2000 Knox and Foresman • Indications for polysomnography Activity Sitting and reading Watching television Sitting inactive in a public place (such as a theater or a meeting) As a passenger in a car for an hour without a break Lying down to rest in the afternoon when circumstances permit Sitting and talking to someone Sitting quietly after a lunch without alcohol In a car, while stopped for a few minutes in the traffic Scale 0 1 2 3 would never doze slight chance of dozing moderate chance of dozing high chance of dozing __________ __________ __________ __________ __________ __________ __________ __________ Figure 1. Adaptation of the Epworth Sleepiness Scale.6 examination, several questionnaires have been introduced. Our practice is to use the Epworth Sleepiness Scale (ESS)6 (Figure 1) at the time of initial assessment in addition to determining the amount of sleep and the sleep pattern. The ESS is a simple, eight-question survey that has been shown to correlate roughly with the MSLT.7 The utility of the ESS is that it provides a semi-quantitative tool for the clinician to identify patients who are pathologically sleepy. Pathologic sleepiness is defined as an inability to control sleep onset or falling asleep at inappropriate times such as while driving a car, during meetings, or while having a conversation. Typically, this level of sleepiness interferes with the daily activities of the patient. Although it has not been fully validated, an ESS score of 8 to 12 is believed by many to be abnormal and deserves further investigation. We define a score of 8 as mild sleepiness, and a score of greater than 12 as moderatesevere sleepiness. A score of 12 correlates with a pathologically short sleep latency ( 5 min) on the MSLT. Beyond the ESS, important information includes details regarding sleep hygiene, sleep-wake schedules, alcohol or medication use, and the propensity for sleep. These aspects of the sleep history help to develop an assessment of factors that may be affecting circadian rhythms, altering sleep architecture, and address complaints related to sleep but not specifically covered by excessive sleepiness (Figure 2). Another helpful tool is to question spouses or roommates about snoring or acting out during sleep. An example of an effective strategy for determining the cause of sleepiness is to ask specific questions regarding a typical night of sleep. An average person requires approximately 6 to 9 hours of sleep a night but can compensate effectively in the short term if sleep time is limited. The less the limitation, the longer the person can maintain daytime performance without significant decrements. If an individual is keeping an intern-type schedule, surfing the Internet until 2 AM, or working several jobs, it will be an expected consequence to have daytime sleepiness. This source of sleepiness would be considered insufficient sleep syndrome or inadequate sleep hygiene and requires behavioral modification. Other situations may arise that require behavioral therapy before initi- ating a referral for sleep study. If a patient complains of insomnia, yet is eating in bed, habitually watching the clock at night, or taking naps during the day, this individual has poor sleep hygiene and needs to be educated regarding an appropriate schedule and habits surrounding bedtime. Often, sleep logs are required to determine the amount of sleep, the sleep pattern, and actual activities ongoing during the night. In some instances, the alteration of the patient’s schedule may only occur under specific circumstance or at certain times of the month. One example is the individual who has excessive sleepiness or insomnia in the perimenstrual period. Such problems have both hormonal and behavioral components that need to be addressed. Disturbances of normal circadian rhythm also can cause sleepiness. Typically, people who travel frequently or those who work different shifts as part of their employment complain of sleepiness and need education in addition to behavior modification. Occasionally, the employers of these patients need to be part of the solution. Fatigue, sleep disorders, and psychiatric illness are at times difficult to differentiate and may coexist.8 Thus, it is important to tailor questions to the individual patient by doing a mini-mental status examination or a screening psychosocial history to rule out underlying anxiety, depression, or other psychiatric disease. A thorough review of symptoms may reveal difficulty concentrating, nocturia, morning headaches, or sexual dysfunction. These symptoms are frequently related to sleep disorders. Physical examination and laboratory testing Physical examination, focusing on the oropharynx, nasopharynx, and related structures, provides useful information that may guide the astute clinician in recognizing coexistent disease that may contribute to the patient’s symptoms. An erythematous posterior aspect of the oropharynx and swollen turbinates may be signs of rhinitis, sinus disease, or postnasal drip that can interfere with sleep or Knox and Foresman • Indications for polysomnography JAOA • Vol 100 • No 8 • Supplement to August 2000 • S23 breathing. In this case, a trial of nasal steroids or antihistamines may be indicated before polysomnography. Micrognathia, increased neck circumference, and other cephalometric abnormalities have been associated with obstructive sleep apnea9 and may help guide the choice of therapeutic interventions. (See article on obstructive sleep apnea (OSA), beginning on page S1.10) In some instances, the evaluation may help to identify other medical disorders or complicating issues such as obesity. Despite the difficulties associated with treating obesity, a multidisciplinary approach to weight loss with formal dietary consultation and exercise routine is likely to benefit this population. Routine blood tests including a complete blood cell count, liver panel, electrolytes, and renal function are warranted in the sleepy patient. It is our practice, despite controversy,11,12 to obtain thyroid function studies early in the evaluation of sleepiness as hypothyroidism is easily treatable. This evaluation may need to be expanded on an individual basis to include a urinalysis, electrocardiography, chest radiography, erythrocyte sedimentation rate, or HIV testing, especially when considering chronic fatigue in the differential diagnosis.8 ✔ Checklist Habits affecting sleep Do you smoke or drink alcohol or caffeinated beverages at night? Do you read, eat, or watch TV in bed? When you awaken at night, what do you do to get back to sleep? Do you watch the clock if you are unable to sleep? Do you sleep in on weekends or regularly take naps? Miscellaneous Do you work at night or on a variable shift? Does pain keep you awake at night? Do you ever awaken with chest pain? Do you have difficult-to-control high blood pressure or heart disease? Do you act out dreams, kick, strike out, or have leg jerks at night? Do you lose control of your muscles when you laugh, startle, or get angry? Do you talk or walk in your sleep, or have you injured anyone during sleep? Sleepiness or fatigue complaints Does excessive sleepiness interfere with daily activities? Do you experience drowsiness while driving? Do you take naps or fall asleep during the day? Do you snore? If so, how frequently? Difficulty going to sleep Do you have difficulty getting to sleep, staying asleep, or returning to sleep after awakening? Do you use over-the-counter or prescription medication to help you sleep? Do you frequently wake up during the night? Do you sleep better on weekends, days off, or when away from home? Do you have difficulty sleeping because of anxiety or worrying? Polysomnography In 1997, the American Sleep Disorder Association published a comprehensive article detailing the indications for polysomnography and related testing.13 These guidelines emphasize the importance of accurately diagnosing sleep disorders to the patient and society. They also caution against indiscriminate use of sleep testing procedures from an economic standpoint. In general, polysomnography is most appropriately and commonly used to assess the abnormally sleepy patient. The most common disorder associated with pathologic sleepiness (Figures 3 and 4) is OSA. In OSA, the upper airway collapses and obstructs airflow, resulting in a recurrent pattern of arousal from sleep often associated with oxygen desaturations. This pattern leaves individuals unrefreshed even after prolonged peri- Figure 2. Questions routinely used while taking a sleep history. ods of sleep and results in the typical complaint of daytime sleepiness. As such, screening appropriate individuals for this disorder is paramount. A history of excessive daytime sleepiness, habitual snoring, a body mass index greater than 35, and witnessed apneas is a clear indication for formal overnight polysomnography as patients with such a history have a greater than 70% probability of having sleep apnea.13 Narcolepsy is a fairly common genetic disorder with the following features: excessive daytime sleepiness (beginning at a young age); cataplexy (sudden loss of muscle tone, but not consciousness); hypnagogic hallucinations (during sleep), and sleep paralysis.14 In contrast to OSA, an MSLT is routinely performed the day after nocturnal polysomnography when attempting to diagnose this disorder.15 Observing sleep-onset rapid-eye-movement (REM) periods during polysomnography or MSLT is highly suggestive of narcolepsy. Polysomnography is also indicated for the diagnosis of periodic limb movement disorder (PLMD). Periodic limb S24 • JAOA • Vol 100 • No 8 • Supplement to August 2000 Knox and Foresman • Indications for polysomnography movements are involuntary, repetitive limb movements that cause arousals and fragmented sleep16 Often, an association with restless legs syndrome exists. Restless legs syndrome (RLS) is a neurologic disorder characterized by unpleasant sensations in the legs that occur at rest and are relieved by movement. Polysomnography is not indicated in the diagnosis or treatment of RLS.13 Parasomnias are phenomena that occur during sleep stages or arise out of transitions from one stage to another. Some of the more common parasomnias include sleep walking and sleep talking; however, some of these disorders can result in injury to the patient or the bed partner (or both). Therefore, they cannot be ignored. Simple parasomnias do not require polysomnography; they include bruxism, enuresis, night terrors, and nightmares. Complicated or violent behaviors need to be investigated with polysomnography and possibly with 24-hour electroencephalographic monitoring. These disorders include seizures, REM-sleep behavior disorder, confusional arousals, and other movement disorders; they often have different etiologies and different modes of therapy. The therapeutic indications for polysomnography, as opposed to the diagnostic ones, include continuous positive airway pressure (CPAP) titration and evaluation of treatment interventions. Patients with neuromuscular disorders and respiratory insufficiency are a special population that should be studied. In addition, sleepiness in truckers or airline pilots warrants testing and follow-up to verify efficacy of treatment. Another common sleep problem is insomnia. Insomnia is defined as difficulty initiating or maintaining sleep. Polysomnography has a limited role in this diagnosis unless sleep-disordered breathing is thought to be the cause of insomnia.17 Many other disorders, however, can present symptomatically as primary insomnia. If other characteristics that warrant polysomnography (PLMD, precipitous arousals, violent behavior, sleep-disordered breathing) coexist with insomnia, then polysomnography may ✔ Checklist Obstructive sleep apnea Narcolepsy Insufficient sleep syndrome ✔ Checklist Sleep-related breathing disorders Obstructive sleep apnea Central sleep apnea syndrome Obesity-hypoventilation syndrome Upper airway resistance syndrome Neurologic and movement disorders Periodic limb movement disorder Seizure disorders Periodic limb movement disorder Restless legs syndrome Shift work sleep disorder Irregular sleep-wake pattern Time zone change syndrome (jet lag) Central sleep apnea syndrome Hypnotic-dependent sleep disorder Figure 3. Common disorders of excessive daytime sleepiness. Parasomnias such as — sleepwalking — nocturnal movements Narcolepsy or hypersomnolence REM-behavior disorder be warranted, especially if symptoms persist despite several attempts at improving sleep hygiene,18 pharmacotherapy, or behavior modification. Therapeutic indications Continuous positive airway pressure titration Assessment of adequacy of sleep-related interventions Respiratory insufficiency (that is, amyotrophic lateral sclerosis) and the titration of noninvasive ventilatory support Alternate testing methods Because of the economic burden associated with standard overnight polysomnography, many have suggested alternative strategies specifically aimed at diagnosing sleep-disordered breathing. Limited diagnostic strategies and portable monitoring are discouraged because of a lack of standardization and the potential for missed diagnosis or improper therapy.19 Currently, only those patients with severe disease that is clinically attributable to OSA, who are unable to be studied expeditiously in a sleep laboratory, should forego standard polysomnography. Alternatively, those patients with known OSA may be able to undergo unattended portable recording for the sole purpose of evaluating response to therapy. Figure 4. Indications for polysomnography. Comment When evaluating the complaint of excessive daytime sleepiness, it is important to determine if the patient is merely tired or falls asleep at inappropriate times. The key element is a detailed sleep history that includes an objective measurement of sleepiness (that is the ESS). We have an algorithm at the Indiana University Center for Sleep Disorders (Figure 5) that is helpful in determining those patients who should undergo polysomnography. If the clinical history is highly suggestive of OSA (excessive daytime sleepiness, snoring, witnessed apneas, obesity), or periodic limb movements (leg jerks Knox and Foresman • Indications for polysomnography JAOA • Vol 100 • No 8 • Supplement to August 2000 • S25 Patient complains of excessive daytime sleepiness (EDS) Take a detailed sleep history Perform thorough physical examination, including the Epworth Sleepiness Scale and a mini-mental status examination History suggests behavioral or untreated medical illness as etiology of EDS History includes: Snoring EDS Witnessed apneas Cardiovascular disease History suggests: Active or violent behaviors during sleep OR Other parasomnias Hypersomnia with no apparent cause or persisting after adequate therapy Correct behavior and/or Treat medical disorder Have patient undergo polysomnography Symptoms resolve Sypmtoms persist Hypersomnia without obstructive sleep apnea (OSA), professional transportation worker, or suspected narcolepsy Diagnosis of OSA or other disorder confirmed by testing Done Multiple Sleep Latency Test (MSLT) Institute treatment and reevaluate No abnormality Pathologic sleepiness without sleep-onset rapid-eyemovement periods (SOREMPs) Sleepiness and SOREMPs noted Assess sleep-wake and circadian patterns Address any medical illness Reevaluate in 6 months Evaluate causes and institute therapy Reevaluate in 1 to 6 months Identify and treat any medical or psychiatric disorders Reevaluate in 1 to 6 months S26 • JAOA • Vol 100 • No 8 • Supplement to August 2000 Knox and Foresman • Indications for polysomnography Figure 5. Algorithm for determining which patients should undergo polysomnography. 5. Benbadis SR, Perry MC, Sundstad LS, Wolgamuth BR. Prevalence of daytime sleepiness in a population of drivers. Neurology 1999;52:209-210. 6. Johns MW. A new method for measuring daytime sleepiness: the Epworth sleepiness scale. Sleep 1991;14:540-545. 7. Chervin RD, Aldrich MS, Pickett R, Guilleminault C. Comparison of the results of the Epworth Sleepiness Scale and the Multiple Sleep Latency Test. J Psychosomat Res 1997;42:145-155. 8. Ward MH, DeLisle H, Shores JH, Slocum PC, Foresman BH. Chronic fatigue complaints in primary care: incidence and diagnostic patterns.JAOA 1996;96:34-46, 41. 9. Sakakibara H, Tong M, Matsushita K, Hirata M, Konishi Y, Suetsugu S. Cephalometric abnormalities in non-obese and obese patients with obstructive sleep apnoea. Eur Respir J 1999;13:403-410. 10. Foresman BH. Sleep and breathing disorders: The genesis of obstructive sleep apnea. JAOA 100(8[Suppl Pt 1]):S1-S10. 11. Skjodt NM, Atkar R, Easton PA. Screening for hypothyroidism in sleep apnea. Am J Respir Crit Care Med 1999;160:732-735. 12. Kapur VK, Koepsell TD, deMaine J, Hert R, Sandblom RE, Psaty BM. Association of hypothyroidism and obstructive sleep apnea. Am J Respir Crit Care Med 1998;158(5 Pt 1):1379-1383. 13. 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. 14. Choo KL, Guilleminault C. Narcolepsy and idiopathic hypersomnolence. Clin Chest Med 1998;19:169181. 15. Aldrich MS, Chervin RD, Malow BA. Value of the multiple sleep latency test (MSLT) for the diagnosis of narcolepsy. Sleep 1997;20:620-629. 16. Chesson AL Jr, Wise M, Davila D, Johnson S, Littner M, Anderson WM, Hartse K, Rafecas J. Practice parameters for the treatment of restless legs syndrome and periodic limb movement disorder. An American Academy of Sleep Medicine Report. Standards of Practice Committee of the American Academy of Sleep Medicine. Sleep 1999;22(7):961-968. 17. Sateia MJ, Doghramji K, Hauri PJ, Morin CM. Evaluation of chronic insomnia. An American Academy of Sleep Medicine review. Sleep 2000;23:243-308. 18. Kupfer DJ, Reynolds CF 3rd. Management of insomnia. N Engl J Med 1997;336:341-346. 19. Practice parameters for the use of portable recording in the assessment of obstructive sleep apnea. Standards of Practice Committee of the American Sleep Disorders Association. Sleep 1994;17:372-377. during sleep) are suspected, a standard polysomnographic recording is likely indicated. After the diagnosis, we use polysomnography to monitor adequacy of surgical interventions for OSA or to determine optimal CPAPs. Moreover, if violent behavior suggests complicated parasomnias, seizures, or REM behavior disorders, a sleep study is indicated. If, however, patients have hallmark features of narcolepsy or objective evidence is needed to determine true excessive daytime sleepiness (especially in occupations such as airline pilots, truck or bus drivers, and air traffic controllers) an MSLT may be needed, as well. References 1. Mitler MM, Miller JC, Lipsitz JJ, Walsh JK, Wylie CD. The sleep of long-haul truck drivers. N Engl J Med 1997;337:755-761. 2. Teran-Santos J, Jimenez-Gomez A, Cordero-Guevara J. The association between sleep apnea and the risk of traffic accidents. Cooperative Group BurgosSantander. N Engl J Med 1999;340:847-851. 3. Peppard PE, Young T, Palta M, Skatrud J. Prospective study of the association between sleep-disordered breathing and hypertension. N Engl J Med 2000;342(19):1378-1384. 4. Lindberg E, Janson C, Svardsudd K, Gislason T, Hetta J, Boman G. Increased mortality among sleepy snorers: a prospective population based study. Thorax 1998;53:631-637. 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