Journal Article w/ Summary
Arianne Diaz (she) on Article
Idiopathic Hypersomnia and Hypersomnolence Disorder: A Systematic Review of the Literature.
Sowa NA.Psychosomatics. 2016 Mar-Apr;57(2):152-64. doi: 10.1016/j.psym.2015.12.006. Epub 2015 Dec 17.PMID: 26895727 Review.
Abstract
Background: Hypersomnia is a common complaint in medical offices. Often patients are given psychiatric diagnoses, but a primary sleep disorder may be present. The new diagnosis of “hypersomnolence disorder” (HD) in the Diagnostic and Statistical Manual of Mental Disorders, fifth edition is a primary sleep disorder most similar to the diagnosis “idiopathic hypersomnia” (IH) in sleep literature and can be missed in psychiatric settings.
Methods: A systematic review of the computerized databases PubMed, EMBASE, Web of Science, and Psychinfo using the search criteria “idiopathic AND (hypersomnolence OR hypersomnia),” as well as “hypersomnolence disorder was conducted.” Articles were included if they were in English and included information regarding the epidemiology, diagnosis, pathophysiology, or treatment of IH or HD. Where relevant, weighted means and 95% CI were calculated based on the number of subjects in each study.
Results: A total of 143 articles discussed IH, whereas no articles were found regarding HD. Most articles were review articles, prospective studies, or studies of pathophysiology. IH is found in approximately 0.02%–0.010% of the general population, has a mean age of onset of 21.8 years, and is associated with several somatic symptoms. Alterations in histaminergic or dopaminergic signaling may be involved in IH. Treatment with modafinil or other stimulants appears moderately effective. IH can be differentiated from psychiatric hypersomnolence by formal polysomnography.
Conclusions: IH and HD are relatively uncommon disorders, and little is known about them. However, they are distinct from psychiatric disorders and respond well to treatment once properly identified.
Type of Study: Systematic Review
Why I Selected This Article
I chose this article because one of my patients is a 24 y/o F that presented to clinic complaining of feeling tired for three months. During my talk with her, she admitted to persistent fatigue unalleviated by rest. This articles goes into depth on one of the differentials I selected for her case, idiopathic hypersomnia. I selected this as one of my differentials for her because my preceptor brought it up as a potential diagnosis. I was not familiar with this condition and wanted to learn more about it.
Summary
Idiopathic hypersomnia is a rare sleep disorder characterized by difficulty staying awake. Patients fall asleep unintentionally or at inappropriate times and may have trouble getting up in the morning. These symptoms are not relieved by adequate sleep and are usually accompanied by a family history of other sleep disorders such as narcolepsy. Hypersomnolence disorder and idiopathic hypersomnia are often used interchangeably but doing so is incorrect. Hypersomnolence disorder is a sleep-wake disorder in which there is “excessive subjective sleepiness despite extended periods of sleep”. The sleep is non-restorative, and the patient has recurrent periods of sleep lapses in the day. There is also a phenomenon known as “sleep drunkenness” that is common amongst these patients. To meet criteria for hypersomnolence disorder, patients must experience symptoms for more than 3 months and have associated functional impairment because of it. Hypersomnolence disorder and idiopathic hypersomnia differ in mean sleep latency and number of sleep-onset REM periods during sleep. For diagnosis of idiopathic hypersomnia there must be a “mean sleep latency of ≤ 8 minutes and < 2 sleep-onset REM periods” during sleep. Authors conducted a systematic search using various databases and only included articles published in English containing information regarding the epidemiology, diagnosis, pathophysiology, treatment, or prognosis or idiopathic hypersomnia or hypersomnolence disorder. 145 articles met the inclusion criteria, and the findings were summarized in a table. According to this study, the mean age of onset for idiopathic hypersomnia is 21.8 years, and the mean sleep latency time was 5.86 minutes. About 30% of patients had a family history of some form of sleep disorder, and 16% experienced associated sleep paralysis. Approximately 80% of these patients experienced memory impairment, and 55% experienced difficulties with attention. Several studies suggest that neurotransmitter abnormalities may contribute to idiopathic hypersomnolence. Orexin is one of the neurotransmitters implicated in this condition as it is associated with wakefulness, arousal, and appetite. This neurotransmitter is found to be decreased in those with narcolepsy with cataplexy. There are other studies which suggest that decreased histamine and serotonin metabolites may be the cause of idiopathic hypersomnolence. It was found that patients had partial/complete improvement in symptoms when managed with modafinil and/or other stimulants such as caffeine, methylphenidate, or dextroamphetamine.
Additional Sources: https://rarediseases.info.nih.gov/diseases/8737/idiopathic-hypersomnia
