Excessive Daytime Sleepiness Case Confounding with Thyrotoxicosis / 수면정신생리

Narcolepsy is a sleep disorder, which is characterized by excessive daytime sleepiness (EDS) that is typically associated with cataplexy, sleep fragmentation and other REM sleep-related phenomenon such as sleep paralysis and hypnagogic hallucination. Narcoleptic symptoms can be developed from various medical or neurological disorders. A 17-year-old male patient admitted for the evaluation of EDS which started three-month ago. He slept more than 18 hours a day with cataplexy and hypnagogic hallucination. He was obese with body mass index (BMI) of 30.4 kg/m2. After admission he was newly diagnosed to the thyrotoxicosis. T3 391.2 ng/dL (60-181), free T4 4.38 ng/dL (0.89-1.76), TSH <0.01 microIU/mL (0.35-5.5) were measured. His pulse rate ranged 70-90 beats per minute and blood pressure ranged 150/100-120/70 mmHg. Polysomnography revealed many fragmentations in sleep with many positional changes (81 times/h). Sleep onset latency was 33.5 min, sleep efficiency was 47.9%, and REM latency from sleep onset was delayed to 153.6 min. REM sleep percent was increased to 27.1%. Periodic limb movement index was 13.4/h. In the multiple sleep latency test (MSLT), average sleep latency was 0.4 min and there were noted 3 SOREMPs (Sleep Onset REM sleep period) on 5 trials. We couldn't discriminate the obvious sleep-wake pattern in the actigraph and his HLA DQB1 *0602 type was negative. His thyroid function improved following treatment with methimazole and propranolol. Vital sign maintained within normal range. Cataplexy was controlled with venlafaxine 75 mg. Subjective night sleep continuity and PLMS were improved with clonazepam 0.5 mg, but the EDS were partially improved with modafinil 200-400 mg. Thyrotoxicosis might give confounding role when we were evaluating the EDS, though sleep fragmentation was one of the major symptoms of narcolepsy, but enormous amount of it made us think of the influence of thyroid hormone. The loss of sleep-wake cycle, limited improvement of EDS to the stimulant treatment, and the cataplexy not supported by HLA DQB1 *0602 should be answered further. We still should rule out idiopathic hypersomnia and measuring CSF hypocretin level would be helpful.

Narcolepsy: Clinical features, co-morbidities & treatment.

Narcolepsy is a neurologic illness that typically begins in the second and third decades of life. It is chronic in nature and negatively impacts the quality of life of affected patients. The classic presentation is a tetrad of excessive daytime sleepiness, cataplexy, sleep paralysis, and hypnagogic hallucinations. The exact cause remains unknown, but there is significant evidence that hypocretin deficiency plays an integral role. Some primary conditions that result in secondary narcolepsy include traumatic brain injury, congenital disorders, tumours, and strokes. Some medical and psychiatric disorders share characteristics of narcolepsy, at times leading to diagnostic inaccuracy. Other sleep disorders are commonly co-morbid. Diagnosis relies on patient history and objective data gathered from polysomnography and multiple sleep latency testing. Treatment focuses on symptom relief through medication, education, and behavioural modification. Both classic pharmacological treatments as well as newer options have significant problems, especially because of side effects and abuse potential. Novel modalities are being examined to expand options for treatment.

Changes in Multiple Sleep Latency Test Results according to Different Criteria of Sleep Onset / 수면정신생리

OBJECTIVES: The multiple sleep latency test (MSLT) is commonly used as a valid objective measure of sleepiness. The procedure of MSLT is well standardized but the sleep onset criterion is somewhat variable. One epoch of stage 1 sleep is the most commonly used criterion, and the criterion of three epochs of stage 1 sleep is also used. The purpose of this study was to compare the two criteria used to determine sleep onset. METHODS: We retrospectively analyzed 60 consecutive MSLT that were performed according to a standaridized protocol. We scored each test using the two different criteria for sleep onset and then statistically analyed the results. RESULTS: Using the different criteria, 20 patients among 60 showed changes in mean sleep latency (33.3%). The extent of change ranged from 1.3% to 38.5% (mean 15.9%). Non-narcoleptic patients showed a significantly higher incidence of change than other sleep disorder patients. CONCLUSION: Changes in mean sleep latency occurred according to the different criteria of sleep onset. But the difference arising from different criteria was statistically not significant in patients with moderate to severe sleepiness. Considering that 1 epoch criterion for sleep onset is more sensitive in detecting clinically significant sleepiness, the authors suggest that the 1 epoch criterion is more reliable than the 3 epochs criterion.

A Case of Narcolepsy after Traumatic Brain Injury / 신경정신의학

The authors reported a case and its diagnostic process of post-traumatic narcolepsy which had developed after a head trauma. The 51-years-old patient showed frequent generalized paralytic attack, which was aggravated during stressful situation, diet time, and in front of hospital staffs. During the paralytic attack, consciousness was alert, and he never collapsed to hurt. All laboratory findings including serum potassium level were within normal limit, and also brain imaging studies and electroencephalography revealed no specific abnormal findings. Our clinical impression was a conversion disorder or a malingering at first, but after the detailed history taking and the careful observation, daytime sleep attack and some sleep problems were revealed. Thus nocturnal polysomnography and multiple sleep latency test(MSLT) were performed, and then the authors could diagnose as "narcolepsy". HLA-DR2 typing was negative. After imipramine trial, the frequency and the intensity of attack was dramatically reduced. The authors concluded that narcolepsy should be considered in the differential diagnosis of sleepiness or transient loss of muscle tone after traumatic brain injury.

Kleine-Levin Syndrome: Two Cases

Kleine-Levin syndrome (KLS) is characterized by recurring episodes of hypersomnia, megaphagia, and abnormal behavior. We report two cases of KLS. Two boys, aged 18 (case 1) and 17 (case 2), had recurrent episodes of hyper-somnolence with compulsive eating or drinking and hypersexuality for several years. HLA-DR typing was HLA-DR3 and 13 in case 1 and HLA-DR4 and 10 in case 2. Case 1 showed hypersomnia with early onset of REM sleep on MSLT and frequent frontal intermittent rhythmic delta activity on EEG. Both cases showed no abnormalities on brain MRI. HLA-DR typing facilitates differentiation between KLS and narcolepsy by the absence of HLA-DR2.