Diagnostic Algorithm for Hypersomnias

Abstract

Sleep disorders are common in the general population, and a complaint of excessive daytime sleepiness (EDS) is one of the primary symptoms of these disorders. EDS is a common symptom in the general population, but still it is often insufficiently recognized. In our modern society, the consequences of EDS may be important as they may lead to an alteration in the quality of life, impairment in work performance, and also an increase in the risk of accidents at work or while driving. Chronic hypersomnia is defined by a constant complaint of EDS, which occurs every day for at least 3 months. Hypersomnia syndromes affect 5–15% of individuals, with a higher prevalence among men in relation to sleep apnea syndromes. Although poor nocturnal sleep could be suspected as an etiology of hypersomnia, EDS is frequently the cardinal symptom of many sleep disorders as reported in the revised International Classification of Sleep Disorders (ICSD-2) such as narcolepsy, idiopathic hypersomnia, recurrent hypersomnia, medication- and toxic-dependent sleepiness, and hypersomnia associated with psychiatric disorders. Considerable progress has been made in the identification of different types of hypersomnia in the last few years; however, a tendency to over diagnose sleep-related breathing disorders in patients with EDS still persists. Physicians dispose several methods (interview, questionnaires, sleep diary, polysomnography, multiple sleep latency test, maintenance of wakefulness test, continuous polysomnography, cerebrospinal fluid hypocretin-1 levels, and human leukocyte antigen typing) to affirm the existence of daytime somnolence and to differentiate between the different causes of hypersomnia, but most of them are insufficiently recognized. The steps for the evaluation of patients with hypersomnia disorders are reviewed in this article, and symptoms and other features that may point to a particular diagnosis are emphasized.