Idiopathic hypersomnia

Introduction
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By Marcel Hungs MD PhD

Idiopathic hypersomnia is also known as or subsumes Essential narcolepsy and Non-rapid eye movement narcolepsy. -ed.

Excessive sleepiness (hypersomnolence) of unknown etiology, which cannot be explained by another disorder, would be considered idiopathic hypersomnia. This should be clearly distinguished from other disorders that could present with complaints of excessive daytime sleepiness, such as narcolepsy, inadequate total sleep time, circadian rhythm disturbance, obstructive sleep apnea, or from hypersomnolence secondary to medical condition or medication. These patients frequently present in adolescence and may have symptoms of autonomic nervous system dysregulation but are most often affected because of inability to attend to daytime obligations such as school or work. Because the pathophysiology is unknown, management is limited to symptomatic treatment and education.

Key Points

  • The main symptom of idiopathic hypersomnia is an irresistible urge to sleep with periods of sleep during the daytime for at least 3 months.
  • For idiopathic hypersomnia duration of sleep (with and without long sleep time) is no longer criteria for subtype distinction.
  • Idiopathic hypersomnia can be associated with symptoms of autonomic nervous system dysregulation (orthostatic hypotension, syncope, headache, and Raynaud-type phenomena) and with significant sleep inertia (aka sleep drunkenness).
  • The diagnosis of idiopathic hypersomnia is based on clinical features along with testing to rule out other causes of excessive daytime sleepiness (Multiple Sleep Latency Test, polysomography, and sometimes actigraphy).
  • The differential diagnosis includes other conditions of excessive daytime sleepiness such as narcolepsy, obstructive sleep apnea, inadequate total sleep time, circadian rhythm disturbance, or hypersomnolence secondary to medical condition or medication.
  • Treatment of idiopathic hypersomnia is primarily symptomatic involving education (sleep hygiene and lifestyle modifications) and wake-promoting agents such as stimulants.

In This Article

Introduction
Historical note and nomenclature
Clinical manifestations
Clinical vignette
Etiology
Pathogenesis and pathophysiology
Epidemiology
Prevention
Differential diagnosis
Diagnostic workup
Prognosis and complications
Management
Pregnancy
Anesthesia
References cited
Contributors