Chapter 028. Sleep Disorders (Part 8) pot

Sleep Disorders Part 8 Insomnia Associated with Neurologic Disorders A variety of neurologic diseases result in sleep disruption through both indirect, nonspecific mechanisms e.g., pai

Chapter 028 Sleep Disorders

(Part 8)

Insomnia Associated with Neurologic Disorders

A 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 The differential diagnosis includes REM sleep behavior disorder, sleep apnea syndrome, and periodic movements of sleep (see above) Diagnosis requires

nocturnal polysomnography with a full EEG montage Other neurologic diseases

associated with abnormal movements, such as Parkinson's disease, hemiballismus,

Huntington's chorea, and Tourette syndrome (Chap 366), are also associated with

disrupted sleep, presumably through secondary mechanisms However, the abnormal movements themselves are greatly reduced during sleep Headache

syndromes (migraine or cluster headache) may show sleep-associated

exacerbations (Chap 15) by unknown mechanisms

Fatal familial insomnia is a rare hereditary disorder caused by degeneration

of anterior and dorsomedial nuclei of the thalamus Insomnia is a prominent early symptom Patients develop progressive autonomic dysfunction, followed by dysarthria, myoclonus, coma, and death The pathogenesis is a mutation in the prion 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 pain from rheumatologic disorders Attention to this association is important in that sleep-associated symptoms are often the presenting or most bothersome complaint

Treatment of the underlying medical problem is the most useful approach Sleep disruption can also result from the use of medications such as glucocorticoids (see below)

One prominent association is between sleep disruption and asthma In

many asthmatics there is a prominent daily variation in airway resistance that results in marked increases in asthmatic symptoms at night, especially during sleep In addition, treatment of asthma with theophylline-based compounds, adrenergic agonists, or glucocorticoids can independently disrupt sleep When sleep 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 The

ischemia itself may result from increases in sympathetic tone as a result of sleep apnea Patients may present with complaints of nightmares or vivid, disturbing dreams, with or without awareness of the more classic symptoms of angina or of the sleep disordered breathing Treatment of the sleep apnea may substantially

improve the angina and the nocturnal sleep quality Paroxysmal nocturnal dyspnea

can also occur as a consequence of sleep-associated cardiac ischemia that causes pulmonary congestion exacerbated by the recumbent posture

Chronic obstructive pulmonary disease is also associated with sleep

disruption, as is cystic fibrosis, menopause, hyperthyroidism, gastroesophageal

reflux, 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 It produces 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 small amounts of coffee can significantly disturb sleep in some patients; therefore, a 1-

to 2-month trial without caffeine should be attempted in patients with these symptoms Similarly, alcohol and nicotine can interfere with sleep, despite the fact that many patients use them to relax and promote sleep Although alcohol can increase drowsiness and shorten sleep latency, even moderate amounts of alcohol increase awakenings in the second half of the night In addition, alcohol ingestion prior to sleep is contraindicated in patients with sleep apnea because of the inhibitory effects of alcohol on upper airway muscle tone Acutely, amphetamines and cocaine suppress both REM sleep and total sleep time, which return to normal with chronic use Withdrawal leads to a REM sleep rebound A number of prescribed medications can produce insomnia Antidepressants, sympathomimetics, and glucocorticoids are common causes In addition, severe rebound insomnia can result from the acute withdrawal of hypnotics, especially

following the use of high doses of benzodiazepines with a short half-life For this reason, hypnotic doses should be low to moderate and prolonged drug tapering is encouraged