Chapter 028. Sleep Disorders (Part 8)

Insomnia Associated with Neurologic DisordersA variety of neurologic diseases result in sleep disruption through both indirect, nonspecific mechanisms (e.g., pain in cervical spondylosis or low back pain) or by impairment of central neural structures involved in the generation and control of sleep itself. For example, dementia from any cause has long been associated with disturbances in the timing of the sleep-wake cycle, often characterized by nocturnal wandering and an exacerbation of symptomatology at night (so-called sundowning).Epilepsy may rarely present as a sleep complaint (Chap. 363). Often the history is of abnormal behavior, at times with convulsive movements during sleep....
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Chapter 028. Sleep Disorders (Part 8) Chapter 028. Sleep Disorders (Part 8) Insomnia Associated with Neurologic Disorders A variety of neurologic diseases result in sleep disruption through bothindirect, nonspecific mechanisms (e.g., pain in cervical spondylosis or low backpain) or by impairment of central neural structures involved in the generation andcontrol of sleep itself. For example, dementia from any cause has long beenassociated with disturbances in the timing of the sleep-wake cycle, oftencharacterized by nocturnal wandering and an exacerbation of symptomatology atnight (so-called sundowning). Epilepsy may rarely present as a sleep complaint (Chap. 363). Often thehistory is of abnormal behavior, at times with convulsive movements during sleep.The differential diagnosis includes REM sleep behavior disorder, sleep apneasyndrome, and periodic movements of sleep (see above). Diagnosis requiresnocturnal polysomnography with a full EEG montage. Other neurologic diseasesassociated with abnormal movements, such as Parkinsons disease, hemiballismus,Huntingtons chorea, and Tourette syndrome (Chap. 366), are also associated withdisrupted sleep, presumably through secondary mechanisms. However, theabnormal movements themselves are greatly reduced during sleep. Headachesyndromes (migraine or cluster headache) may show sleep-associatedexacerbations (Chap. 15) by unknown mechanisms. Fatal familial insomnia is a rare hereditary disorder caused by degenerationof anterior and dorsomedial nuclei of the thalamus. Insomnia is a prominent earlysymptom. Patients develop progressive autonomic dysfunction, followed bydysarthria, myoclonus, coma, and death. The pathogenesis is a mutation in theprion gene (Chap. 378). Insomnia Associated with Other Medical Disorders A number of medical conditions are associated with disruptions of sleep.The association is frequently nonspecific, e.g., sleep disruption due to chronic painfrom rheumatologic disorders. Attention to this association is important in thatsleep-associated symptoms are often the presenting or most bothersome complaint.Treatment of the underlying medical problem is the most useful approach. Sleepdisruption can also result from the use of medications such as glucocorticoids (seebelow). One prominent association is between sleep disruption and asthma. Inmany asthmatics there is a prominent daily variation in airway resistance thatresults in marked increases in asthmatic symptoms at night, especially duringsleep. In addition, treatment of asthma with theophylline-based compounds,adrenergic agonists, or glucocorticoids can independently disrupt sleep. Whensleep disruption is a side effect of asthma treatment, inhaled glucocorticoids (e.g.,beclomethasone) that do not disrupt sleep may provide a useful alternative. Cardiac ischemia may also be associated with sleep disruption. Theischemia itself may result from increases in sympathetic tone as a result of sleepapnea. Patients may present with complaints of nightmares or vivid, disturbingdreams, with or without awareness of the more classic symptoms of angina or ofthe sleep disordered breathing. Treatment of the sleep apnea may substantiallyimprove the angina and the nocturnal sleep quality. Paroxysmal nocturnal dyspneacan also occur as a consequence of sleep-associated cardiac ischemia that causespulmonary congestion exacerbated by the recumbent posture. Chronic obstructive pulmonary disease is also associated with sleepdisruption, as is cystic fibrosis, menopause, hyperthyroidism, gastroesophagealreflux, chronic renal failure, and liver failure.[newpage] Medication-, Drug-, or Alcohol-Dependent Insomnia Disturbed sleep can result from ingestion of a wide variety of agents.Caffeine is perhaps the most common pharmacologic cause of insomnia. Itproduces increased latency to sleep onset, more frequent arousals during sleep,and a reduction in total sleep time for up to 8–14 h after ingestion. Even smallamounts of coffee can significantly disturb sleep in some patients; therefore, a 1-to 2-month trial without caffeine should be attempted in patients with thesesymptoms. Similarly, alcohol and nicotine can interfere with sleep, despite the factthat many patients use them to relax and promote sleep. Although alcohol canincrease drowsiness and shorten sleep latency, even moderate amounts of alcoholincrease awakenings in the second half of the night. In addition, alcohol ingestionprior to sleep is contraindicated in patients with sleep apnea because of theinhibitory effects of alcohol on upper airway muscle tone. Acutely, amphetaminesand cocaine suppress both REM sleep and total sleep time, which return to normalwith chronic use. Withdra ...