33. A 32-year-old woman presents with a complaint of difficulty maintaining sleep of 4 years’ duration. The problem began when she was on a vacation in Europe. She was unable to sleep throughout the 2-week vacation, and the insomnia did not improve following her return home. Once asleep, she reports having light sleep and decreased sleep quality. She will sleep better one or two nights per week. She reports significant fatigue during waking hours. She gives no history of snoring or limb move- ments during sleep. Her BMI is 24 kg/m2. She denies medical disorders, and she takes no medication. She did take zolpidem 10 mg, 2 years ago, with significant improvement. However, she did not want to be dependent on medication and discontin- ued this. There is no clinical evidence of increased anxiety or depression at the present time. Her sleep log for the prior 2 weeks is shown in Figure 33A. Based on the history and sleep log findings, the best diagnosis for this patient is: A. Insomnia due to mental disorder. B. Psychophysiologic insomnia. C. Idiopathic insomnia. D. Inadequate sleep hygiene. Figure 33A 33. B. Psychophysiologic insomnia. Psychophysiologic (or “conditioned”) insomnia often begins with a precipitating event that may no longer be relevant since the insomnia becomes conditioned over time. In this instance, the patient was sleeping poorly due to a presumed combination of jet lag and environmental factors. Those factors are no longer a concern, but her sleep log does illustrate a continued decrease in total sleep time, which is needed to diagnose insomnia (choice B is correct). The sleep log shows regular bedtimes and arising times, no napping, and no excessive caffeine use or other behavior as would be required to make a primary diagnosis of inadequate sleep hygiene. Therefore, there is no evidence that the primary diagnosis is inadequate sleep hygiene (choice D is incorrect). This diagnosis is much more often a secondary, rather than a primary, diagnosis. Idiopathic insomnia would be expected to have started when the patient was much younger (answer C is incorrect). The differential diagnosis between psychophysiologic insomnia and insomnia due to mental disorder can be a very difficult one. This is because in both instances the insomnia can begin very abruptly in conjunction with stressful life events. In particular, a patient with psychophysiologic insomnia may appear to be very anxious and excessively tense at night, as might be observed in a patient with a psychiatric disorder. In the case of a psychiatric disorder, it is expected that more pervasive symptoms will be observed than those associated with sleep. In the case of psychophysiologic insomnia, it is expected that the patient is doing well in other areas and may only experience anxiety in connection with their concerns about sleep. In the present case, a psychiatric disorder must still be ruled out but is not diagnosable based on this history and sleep log (answer A is incorrect). Edinger JD, Means MK. Overview of insomnia: definitions, epidemiology, differential diagnosis, and assessment. In: Kryger M, Roth T, Dement W, eds. Principles and practice of sleep medicine. 4th ed. Philadelphia, PA: Elsevier/Saunders, 2005; 702-713 American Academy of Sleep Medicine. ICSD-2–International classification of sleep disorders: diagnostic and coding manual. 2nd ed. Westchester, IL: American Academy of Sleep Medicine, 2005 39. A 26-year-old man with a medical history of asthma presents, complaining of daytime sleepiness. He is a second-year student in veterinary school and just started his clinical rotations. His girlfriend says he snores loudly. He also tosses and turns all night; sometimes he kicks her. He drinks four to six cups of coffee per day in order to stay awake, but he is concerned because his grades are slipping, and he caught himself falling asleep during a long surgical procedure. His Epworth Sleepiness Scale score is 21/24. He denies any discomfort in his legs during the daytime or that prevents him from falling asleep or staying asleep. He is on montelukast for his asthma and albuterol MDI as needed. He denies alcohol, tobacco, or recreational drug use. His body mass index is 28.3 kg/m2. His examination is unremarkable. A PSG is performed. The sleep study data are as follows: Polysomnographic data: AHI 2/h PLM index 32/h Snoring Loud The 30-s epoch shown in Figure 39A is noted 1 min after sleep onset. What should you do next? A. Prescribe clonazepam. B. Prescribe ropinirole. C. Bring the patient back into the sleep laboratory for a repeated PSG with an expanded seizure montage. D. Bring the patient back into the sleep laboratory for a repeated PSG, followed by a daytime multiple sleep latency test. Figure 39A 39. D. Bring the patient back into the sleep laboratory for a repeated PSG, followed by a daytime multiple sleep latency test. The epoch in Figure 39A depicts REM sleep. The presence of a low amplitude, mixed frequency EEG with low chin EMG tone, as well as REMs, meets criteria for REM sleep. Note the triangular waves at 2- to 6-Hz frequency at the beginning of the epoch. These are called sawtooth waves. Sawtooth waves are best seen in the central electrodes and frequently occur prior to a burst of REMs. In a relatively young individual with nearly normal sleep amounts who complains of excessive daytime sleepiness, a REM sleep onset latency of 1 min is suggestive of possible narcolepsy. Other shortened REM latencies may also be seen in individuals with untreated obstructive sleep apnea, depression, or prior REM deprivation. In the present clinical scenario, there is no evidence of sleep apnea or depression. He is likely sleep restricted from his baseline since starting his clinical rotations, which could account for his symptoms and this short REM latency. Narcolepsy is a distinct possibility and should be assessed with a sleep diary for at least 1 week prior to a repeated polysomnography with at least 6 h of sleep, followed by a multiple sleep latency test (choice D is correct). Clonazepam is a long-acting benzodiazepine that can be used as therapy for insomnia, somnambulism (ie, sleepwalking), and related diseases. However, sleepwalking does not appear to be an active issue presently, despite the patient’s relative sleep restriction, and there is nothing on the PSG report or 30-s epoch that would suggest treatment of a non-REM parasomnia with clonazepam (choice A is incorrect). Clonazepam can be used as a therapy for REM sleep behavior disorder (RBD), but there is nothing in the history or in the epoch of REM sleep to suggest RBD. There is nothing in his history to suggest restless legs syndrome, for which ropinirole would be appropriate treatment (choice B is incorrect). While nocturnal seizures are possible in an individual who is restless and kicking at night, in this particular patient, given the history of excessive sleepiness, the shortened REM latency, and the findings of periodic limb movements, narcolepsy should be considered next on the differential. The need for an expanded seizure montage and/or treatment for his periodic limb movement disorder could be reevaluated at a later time (choice C is incorrect). Iber C, Ancoli-Israel S, Chesson A, et al, for the American Academy of Sleep Medicine. The AASM manual for the scoring of sleep and associated events: rules, terminology and technical specifications. Westchester, IL: American Academy of Sleep Medicine, 2007; 42-43 Littner MR, Kushida C, Wise M, et al. Practice parameters for the clinical use of the multiple sleep latency test and the maintenance of wakefulness test. Sleep 2005; 28:113-121 Littner MR, Kushida C, Anderson WM, et al. Practice parameters for the dopaminergic treatment of restless legs syndrome and periodic limb movement disorder. Sleep 2004; 27:557-559 Nishino S. Clinical and neurobiological aspects of narcolepsy. Sleep Med Clin 2007; 8:373-399.