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.

Prevalence of the HLA-DQB1*0602 allele in narcolepsy and idiopathic hypersomnia patients seen at a sleep disorders outpatient unit in São Paulo / Prevalência do alelo HLA-DQB1*0602 em pacientes com narcolepsia e hipersonolência idiopática atendidos em ambulatório de sonolência em São Paulo

OBJECTIVE: Narcolepsy (with and without cataplexy) and idiopathic hypersomnia, are disorders with common features but with different HLA-DQB1*0602 allele prevalence. The present study describes the prevalence of HLA-DQB1*0602 allele in narcoleptics with and without cataplexy and in patients with idiopathic hypersomnia. METHOD: Subjects comprised 68 patients who were diagnosed for narcolepsy or idiopathic hypersomnia and 23 healthy controls according to the International Classification of Sleep Disorders-2. Subjects comprised 43 patients with narcolepsy and cataplexy, 11 patients with narcolepsy but without cataplexy, 14 patients with idiopathic hypersomnia and 23 healthy controls. Genotyping of HLA-DQB1*0602 allele was performed for all subjects. RESULTS: The prevalence of the HLA-DQB1*0602 allele was increased in idiopathic hypersomnia and in narcoleptic patients with and without cataplexy when compared to healthy subjects (p = 0.04; p = 0.03 and p < 0.0001, respectively). CONCLUSIONS: This finding is in accordance with those of previous studies. The gold standard exam of narcolepsy with cataplexy is Hypocretin-1 dosage, but in patients without cataplexy and idiopathic hypersomnia, there are no specific diagnostic lab findings. The presence of the HLA-DQB1* 0602 allele may be important for the differential diagnosis of situations that resemble those sleep disorders such as secondary changes in sleep structure due to drugs' consumption.

OBJETIVO: Narcolepsia (com e sem cataplexia) e hipersonolência idiopática são transtornos com características clínicas comuns, mas com prevalências do alelo HLA-DQB1*0602 diferentes. Este estudo descreve a prevalência do alelo HLA-DQB1*0602 em pacientes narcolépticos com e sem cataplexia e em pacientes com hipersonolência idiopática. MÉTODO: A amostra consistiu de 68 pacientes com diagnóstico de narcolepsia ou hipersonolência idiopática e 23 controles saudáveis segundo o International Classification of Sleep Disorders-2. A amostra foi composta de 43 pacientes com narcolepsia e cataplexia, 11 pacientes com narcolepsia e sem cataplexia, 14 pacientes com hipersonolência idiopática e 23 controles saudáveis. A análise da presença do alelo HLA-DQ*0602 foi realizada em todos os sujeitos. RESULTADOS: A prevalência do alelo HLA-DQB1*0602 foi maior nos grupos de pacientes com hipersonolência idiopática e em pacientes narcolépticos com e sem cataplexia quando comparada com a dos sujeitos saudáveis (p = 0,04; p = 0,03 e p < 0,0001, respectivamente). CONCLUSÕES: Os resultados são compatíveis com o de estudos anteriores. O exame padrão-ouro para a confirmação da narcolepsia em pacientes com cataplexia é a dosagem de hipocretina, mas em pacientes sem cataplexia e hipersonolência idiopática não há testes laboratoriais específicos para o diagnóstico. A presença do alelo HLA-DQB1*0602 pode ser importante no diagnóstico diferencial de situações semelhantes a esses distúrbios do sono, como alterações secundárias na estrutura do sono causadas por consumo de drogas.

The Sleepy Child / 수면정신생리

Excessive daytime sleepiness in childhood might be abnormal phenomenon and often related to the sleep disorders or insufficient sleep duration. The most common cause of excessive daytime sleepiness would be insufficient sleep. However, narcolepsy, idiopathic hypersomnia, circadian rhythm sleep disorders, medication, medical illness and other sleep disorders that could cause insomnia and poor quality of sleep also result in excessive daytime sleepiness. The misdiagnosed and untreated excessive daytime sleepiness in childhood can lead to serious developmental and educational problem.