|Year : 2007 | Volume
| Issue : 1 | Page : 58-60
A case of primary hypersomnia
Dinesh J John, Arun Manoharan, Roy Varghese
Department of Internal Medicine, Mary Breckinridge Hospital, Hyden, KY, USA
Infectious Diseases and Internal Medicine, Mary Breckinridge Hospital, Hyden, KY
| Abstract|| |
Primary hypersomnia (PH) is a disorder of presumed central nervous system etiology that is associated with a normal or prolonged major sleep episode and excessive sleepiness consisting of prolonged (one or two hour) episodes of non-rapid eye movement sleep. It has a similar presentation to narcolepsy, but is not generally associated with cataplexy or sleep-onset rapid eye movement. Although PH is a chronic disorder, fluctuations and spontaneous remissions are known to occur. Treatment with stimulants is beneficial in most patients. We present the case of a 32-year-old Caucasian woman with the classical features of PH. Her condition has progressed over the years and she sleeps for days on end or until aroused. She has been treated with multiple stimulants, with limited success. This case highlights the clinical presentation, diagnostic criteria and treatment modalities of this rare condition.
Keywords: HLA-Cw 2, hypersomnia, hypocretin-1, narcolepsy
|How to cite this article:|
John DJ, Manoharan A, Varghese R. A case of primary hypersomnia. Ann Indian Acad Neurol 2007;10:58-60
| Introduction|| |
Primary hypersomnia (PH) is a disorder of presumed central nervous system etiology that is associated with a normal or prolonged major sleep episode and excessive sleepiness consisting of prolonged (one or two hour) episodes of non-rapid eye movement sleep. It is a profoundly disabling disorder, often disrupting the patient's work, family life and interpersonal ties. Current views are derived largely from the work of Bedrich Roth, who described this syndrome as being distinct from narcolepsy. Both these conditions are idiopathic and usually present as excessive daytime sleepiness, but cataplexy or periods of sleep-onset rapid eye movement are not usually seen in PH. Polysomnography is the diagnostic test of choice [Table - 1]. Treatment with stimulants and less commonly with antidepressants, is beneficial in three quarters of the patients. A new compound, modafinil, has been shown to produce good results in these patients. We present the case of a 32-year-old Caucasian woman with the unusual ability to sleep for days on end or until aroused and diagnosed with PH.
| Case Report|| |
A 32-year-old Caucasian woman came to us with complaints of excessive daytime sleepiness (EDS). She had no problems with her sleep or general health until two years before, when she began to experience excessive daytime fatigue. Her condition progressed and at the time of presentation she was able to sleep for extended periods of time (up to two to three days at a stretch) and still be hypersomnolent in the day. On questioning, she denied cataplexy, hypnagogic hallucinations or sleep paralysis. There was no prior history of closed head injury, meningitis or any focal cerebrovascular symptoms. During her initial diagnostic work-up for fatigue, she was found to have a mildly elevated TSH level. She was started on thyroxine, but her symptoms persisted (in spite of TSH value subsequently returning to normal). She had been working in an office setting, but quit her job a month before on account of her EDS and difficulty in concentrating. She stopped driving because she had found herself in the wrong lane on occasion and not sure how she got there. She is married with two children and there is no family history of excessive daytime sleepiness. Her periods have been regular throughout the duration of her condition. There was no change in her appetite. However, she stated she would drink about 12 cans of caffeinated soft drinks per day. She smokes half a pack of cigarettes a day, but does not take alcohol or any recreational drugs. Her medications included diphenhydramine for allergic rhinitis.
Physical examination was unremarkable, except that the patient appeared sleepy and yawned several times during the interview. She was of average height and weight and lean in build. Body temperature was 37.1º C. Visual field-testing by confrontation revealed no abnormality. There was no clinical evidence of any focal neurological deficit. Laboratory tests revealed the following: TSH level of 15.1 mIU/L (normal: 0.3-5.0 mIU/L), free thyroxine level of 1.0 ng/dl (within normal reference range). Her ACTH stimulation test, Epstein-Barr virus and cytomegalovirus serologies were all normal. MRI did not reveal any structural abnormalities in the brain. The patient underwent a nocturnal polysomnography, followed by a Multiple Sleep Latency Test (MSLT). All stimulant medications were stopped one week prior to this study. The results were as follows:
- Total recording time of 7.5 hours, with a total sleep time of 6.8 hours (sleep efficiency of 90.2%).
- Latency to sleep onset of 28 minutes; latency to rapid eye movement (REM) sleep of 175.5 minutes.
- Wakefulness 9.8%, NREM sleep 77%, REM sleep 13.4%.
- No respiratory abnormalities.
- EKG rate of 63 bpm, with no arrhythmia.
- 128 periodic leg movements with a myoclonus index of 18.9. Accompanying arousal index of 2.2.
- Mean Sleep Latency of 4.6 minutes.
Based on the clinical picture as well as the above polysomnographic findings, a diagnosis of PH was made. Treatment was initiated with methylphenidate 10 mg b.i.d and pemoline 18.5 mg t.i.d. At the prescribed doses, she was not able to stay alert and would take up to 150 mg of each of these. She subsequently developed edema of the hands and feet, for which she discontinued methylphenidate. Due to the safety concerns regarding pemoline, she stopped taking this drug. At the moment, the patient is doing relatively well on modafinil 100 mg b.i.d and methamphetamine 10 mg t.i.d and can manage some household work in the daytime. She has switched to cetirizine for her seasonal allergy.
| Discussion|| |
Primary hypersomnia (PH) is a disorder that is associated with a normal or prolonged major sleep episode and excessive daytime sleepiness consisting of prolonged episodes of non-rapid eye movement sleep. Familial cases are known to occur, with an HLA-Cw2 association. PH has been found to be associated with low cerebrospinal fluid levels of Hypocretin-1, a neuropeptide thought to be synthesized in the lateral hypothalamus. It is important to note that PH is essentially a diagnosis of exclusion. Conditions having a similar presentation are narcolepsy [Table - 2], insufficient sleep syndrome, medication- and toxin-dependent sleepiness, hypersomnia associated with psychiatric disorders, hypersomnia associated with neurological disorders, posttraumatic hypersomnia, infection hypersomnia associated with metabolic or endocrine diseases, breathing-related sleep disorders and sleep apnea syndromes and periodic limb movements in sleep.
The patient under reference satisfied the diagnostic criteria of PH [Table - 1]. Other conditions were excluded with the help of a detailed history and physical examination, as well as appropriate laboratory investigations. The patient did not have any of the cataplexy, hypnagogic hallucinations or sleep paralysis associated with narcolepsy; nor was there any clinical or radiological evidence of a structural lesion of the hypothalamus. She did take diphenhydramine occasionally, but EDS persisted when she switched to cetirizine. She was treated for hypothyroidism, which did not cause any improvement of her symptoms. Polysomnography revealed findings consistent with PH: normal sleep time, good sleep efficiency and reduced Mean Sleep Latency. REM sleep duration was reduced, probably due to the effect of the patient's stimulant medications. Neither the sleep latency nor REM latency were decreased, as is the case in patients with narcolepsy. The myoclonus index was increased without any accompanying increase in the arousal index, excluding a diagnosis of restless leg syndrome. No respiratory abnormalities were found to suggest sleep apnea syndrome.
The management of PH often requires a multi-pronged approach involving pharmacologic as well as non-pharmacologic measures. Good sleep hygiene is of utmost importance. This involves the following: using the bed for sleep and sex only, avoiding stimulants such as tobacco and caffeine close to bedtime, limiting fluid intake after 8pm and napping (only if needed) about eight hours after awakening for a maximum of 25 minutes. The patient's work situation can be improved if the employer is aware of this condition. Regular breaks or planned short naps are helpful if the tasks at hand involve immobility or prolonged concentration. The most suitable work would involve exercise and a stimulating environment e.g., shop assistant, hairdresser or porter. As far as driving is concerned, the patient has a duty to notify the authorities and his/her insurance company. A license is usually issued for one to three years, pending a medical report on fitness to drive. A good strategy would be to nap before driving and to take time stimulant medication (if needed) for optimal alertness when driving. The patient must pull over and stop driving immediately if he/she feels drowsy. Pharmacotherapy should only be initiated if the non-pharmacological measures fail. The first line stimulant is caffeine. If increasing the patient's caffeine intake does not cause any improvement, other drugs such as methylphenidate, d-amphetamine and modafinil can be tried. Suggested regimens include the use of modafinil on a daily basis, with d-amphetamine taken before activities requiring alertness. About three-quarters of patients benefit from these stimulant medications.
To summarize, a diagnosis of PH should only be made after carefully ruling out other causes of EDS. With the appropriate non-pharmacologic and pharmacologic treatment, the quality of life in these patients can be improved to a great extent.
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[Table - 1], [Table - 2]