Narcolepsy

Introduction
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By Antonio Culebras MD

Narcolepsy is also known as or subsumes Hypersomnia with REM sleep abnormalities. -ed.

In this clinical article, the author reviews the current information on narcolepsy, a disease that has progressed in only 50 years from a quasi-psychiatric condition to a true neurologic disorder. New knowledge of the etiology and mechanism of the disease relative to the hypocretins has opened a major pathway to understanding excessive sleepiness not only in narcolepsy but also in other sleep disorders. Most cases of narcolepsy with cataplexy are associated with the loss of approximately 50,000 to 100,000 hypothalamic neurons containing hypocretin. Pharmacologic treatment remains symptomatic but increasingly effective.

Key Points

  • Narcolepsy is characterized by excessive daytime sleepiness.
  • The classic form of narcolepsy (narcolepsy type 1) features cataplexy, sleep paralysis, and hypnagogic hallucinations.
  • Some patients with otherwise typical features of narcolepsy do not have cataplexy; this is a condition referred to as monosymptomatic narcolepsy or narcolepsy without cataplexy (narcolepsy type 2).
  • The observation that narcolepsy was associated with human leukocyte antigens (HLA)-DR2 was the first indication of a biologically based source.
  • The discovery of a significant decrease of the neurotransmitter hypocretin-1 levels in cerebrospinal fluid in patients with narcolepsy-cataplexy provided a new test to diagnose the condition.
  • Administration of gamma hydroxybutyrate (GHB) has been confirmed as an efficacious treatment of narcoleptic symptoms.

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