MEDizzy - A 42-year-old man is evaluated for excessive sleepiness that

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Cardinal Manifestations and Presentation of Diseases 2

A 42-year-old man is evaluated for excessive sleepiness that is interfering with his ability to work. He works at a glass factory that requires him to work rotating shifts. He typically cycles across day (7 AM–3 PM), evening (3 PM–11 PM), and night (11 PM–7 AM) shifts over the course of 4 weeks. He notes the problem to be most severe when he is on the night shift. Twice he has fallen asleep on the job. While no accidents have occurred, he has been threatened with loss of his job if he falls asleep again. His preferred sleep schedule is 10 PM until 6 AM, but even when he is working day shifts, he typically only sleeps from about 10:30 PM until 5:30 AM. However, he feels fully functional at work on day and evening shifts. Following his night shifts, he states that he fnds it difcult to sleep when he frst gets home, frequently not falling asleep until 10 AM or later. He is up by about 3 PM when his children arrive home from school. He drinks about 2 cups of cofee daily, but tries to avoid drinking more than this. He does not snore and has a body mass index of 21.3 kg/m2. All of the following are reasonable approaches to treatment in this gentleman EXCEPT:

ExplanationShift work sleep disorder is a disorder of the circadian rhythm that is common in any individual who has to commonly work at night. At present, an estimated 7 million individuals in the United States work permanently at night or on rotating shifts. Increasing research devoted to sleep disorders in night shift workers has demonstrated that the circadian rhythm never fully shifts to allow one to perform at full alertness at night. The reason for this is likely multifactorial and includes the fact that most individuals who work at night try to abruptly shift their sleep schedules to a more normal pattern on days when they are not working. Consequently, night shift workers often have chronic sleep deprivation, increased length of time awake prior to starting work, and misalignment of their circadian phase with the intrinsic circadian phase, which result in decreased alertness and increased errors during night shifts. In an estimated 5%–10% of individuals working night shifts, the excessive sleepiness during the night and insomnia during the day are deemed to be clinically signifcant. Strategies for treating shift work sleep disorder utilize a combination of behavioral and pharmacologic strategies. Cafeine does promote wakefulness, but the efects are not long-lasting and tolerance develops over time. Brief periods of exercise frequently boost alertness and can be used prior to starting a night shift or during the shift at times of increased sleepiness. Many sleep experts support strategic napping during shifts for no more than 20 minutes at times of circadian nadirs. Naps longer than 20 minutes can lead to sleep inertia during which an individual may feel very disoriented, groggy, and experience a decline in motor skills upon abrupt awakening from sleep. Bright lights prior to and during night shift work may improve alertness, but one must be careful to avoid bright lights in the morning following a night shift as light entrainment is a powerful stimulus of the internal circadian clock. If an individual is exposed to bright light in the morning, it will interfere with the ability to fall asleep during the day. Night shift workers should be encouraged to wear dark sunglasses in the morning on the way home. Sleep during the day is frequently disrupted in night shift workers. Creating a quiet, dark, and comfortable environment is important, and sleep should be a priority for the individual during the day. The only pharmacologic therapy approved by the FDA for treatment of shift work sleep disorder is modafnil 200 mg taken 20–30 minutes prior to the start of a night shift. Modafnil has been demonstrated to increase sleep latency and decrease attentional failures during night shifts, but it does not alleviate the feelings of excessive sleepiness. Melatonin is not one of the recommended therapies for shift work sleep disorder. If used, it should be taken 2–3 hours prior to bedtime, rather than right before bedtime, to simulate the normal peaks and troughs of melatonin secretion.