Narcolepsy

Abstract

Narcolepsy is a life-long neurological, rapid eye movement (REM) sleep disorder. Most frequent symptoms involve excessive daytime sleepiness, cataplexy, hypnagogic hallucinations, sleep paralysis, and disrupted night-time sleep. The estimated prevalence of narcolepsy is 0.05%. Initial symptoms usually start in childhood and young adults. Diagnosis of narcolepsy is often problematic, and it can take up to 20 years between the first observed excessive sleepiness and a fully developed disorder. Both genetic and environmental contribute to narcolepsy onset. A very strong association was observed in the case of human leukocyte DQ antigens, especially DQB1_0602. We distinguish narcolepsy type 1 and 2. Diagnosis of both types is based on the patient’s history, confirmed by multiple sleep latency test (MLST) with preceding polysomnography (PSG). Highly specific findings in these examinations are SOREMPs – occurrence of REM period within 15 minutes after falling asleep. In narcolepsy type 1 cataplexy is present, and CSF hypocretin-1 concentration is undetectable as opposed to narcolepsy type 2. Early diagnosis and implemented treatment can significantly improve the quality of life of patients with narcolepsy. Non-pharmacological treatment such as good sleep habits and daytime naps play an important role in better symptom control. Pharmacological treatment helps to overcome hypersomnia and cataplexy. This review includes the most important clinical features of narcolepsy.