Sleep Med Psychophysiol.  2011 Jun;18(1):40-44.

Excessive Daytime Sleepiness Case Confounding with Thyrotoxicosis

• Chung JK
• Kim EJ

Abstract

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.

Keyword

Excessive daytime sleepiness; Thyrotoxicosis; Polysomnography; Multiple sleep latency test (MSLT); Actigraph

MeSH Terms

Adolescent
Benzhydryl Compounds
Blood Pressure
Body Mass Index
Cataplexy
Clonazepam
Cyclohexanols
Extremities
Hallucinations
Heart Rate
HLA-DQ beta-Chains
Humans
Hypersomnolence, Idiopathic
Intracellular Signaling Peptides and Proteins
Male
Methimazole
Narcolepsy
Nervous System Diseases
Neuropeptides
Polysomnography
Propranolol
Reference Values
Sleep Deprivation
Sleep Paralysis
Sleep, REM
Thyroid Gland
Thyrotoxicosis
Vital Signs
Orexins
Venlafaxine Hydrochloride
Benzhydryl Compounds
Clonazepam
Cyclohexanols
HLA-DQ beta-Chains
Intracellular Signaling Peptides and Proteins
Methimazole
Neuropeptides
Propranolol