[Narcolepsy]

Abstract

Narcolepsy is a rare sleep disorder. The classical presentation includes the four symptoms excessive daytime sleepiness, cataplexy, sleep paralysis and hypnagogic hallucinations. As a model disease with all the transitions from awake to sleeping conditions, non-rapid eye movement (NREM) and rapid eye movement (REM), it plays an important role in neurology and sleep medicine. Patients with narcolepsy possess a reduced number of hypocretin-producing neurons in the hypothalamus and accordingly the hypocretin level in the cerebrospinal fluid is low. The neuropeptide hypocretin (orexin) has functions, such as the regulation of the sleep-wake cycle, the autonomous nerve system, motor system and metabolic processes. The delay in diagnosing narcolepsy is difficult to comprehend in modern medicine. The frequent association with other sleep-wake disorders may be responsible for the delay. Genomewide association studies have subsequently been able to prove that autoimmune mechanisms are responsible for the manifestation of narcolepsy with the HLA association being the most important for susceptibility and protection. Imaging studies have revealed neurodegenerative changes, making a multifactorial etiopathogenesis probable. The frequent occurrence of metabolic disorders has not yet been clarified. Early diagnosis of narcolepsy has the possibility to offer affected persons an adequate medication to lead an almost normal life and the future possibility to cure narcolepsy through immunomodulation therapy.