Narcolepsy is a neurological disorder that affects the sleep-wake cycle. It belongs to the hypersomnia with a central cause.
There are various forms of narcolepsy: narcolepsy with cataplexy ("classic narcolepsy"), narcolepsy without cataplexy (monosymptomatic narcolepsy) and secondary narcolepsy (symptomatic, for example, in structural lesions of the hypothalamus or upper brainstem as a result of ischemia or tumor).
Characteristic of all forms is more than 6 months existing daytime sleepiness associated with uncontrollable sleep. Most patients are additionally affected by cataplectic seizures, which lead to a sudden loss of muscle tone. Typical triggers are laughter, joy, anger, fear or other strong emotions.
Symptoms begin at the age of 10 to 30 years, after which narcolepsy with variable intensity of symptoms persists throughout life. Cataractic narcolepsy is due to a loss or dysfunction of the lateral hypothalamic orexin / hypocretin neurons resulting in decreased levels of cerebrospinal fluid in the cerebrospinal fluid.
In narcolepsy without cataplexy this finding can rarely be raised. The cause is unclear, infectious triggers and autoimmune processes are discussed. Furthermore, there is a strong association with certain HLA-II phenotypes. The educational and occupational benefits of patients can be severely affected by the disease.
In the course of the disease, narcolepsy often remains stable. While daytime sleepiness and cataplexy often improve, the quality of nighttime sleep decreases with age.