Narcolepsy

Narcolepsy is a chronic neurological disorder that impairs the ability to regulate sleep–wake cycles, and specifically impacts REM (rapid eye movement) sleep. The symptoms of narcolepsy include excessive daytime sleepiness (EDS), sleep-related hallucinations, sleep paralysis, disturbed nocturnal sleep (DNS), and cataplexy. People with narcolepsy typically have poor quality of sleep. There are two recognized forms of narcolepsy: type 1 and type 2. Narcolepsy type 1 features EDS with either cataplexy or cerebrospinal fluid (CSF) orexin levels of less than 110 pg/ml, but most cases present with both. Cataplexy appears as transient episodes of aberrant muscle tone (typically loss of muscle tone) triggered by strong emotion. In pediatric-onset narcolepsy, cataplexy can present with transient hyperkinetic features. Cataplexy may be mistaken for syncope, tics, or seizures. Narcolepsy type 2 (NT2) does not feature cataplexy, and CSF orexin levels are normal. Sleep-related hallucinations, both hypnagogic (going to sleep) and hypnopompic (on awakening), can be auditory, visual, or tactile and may occur independently of or in combination with an inability to move (sleep paralysis). Narcolepsy is a clinical syndrome of hypothalamic disorder, but the exact cause of narcolepsy is unknown, with potentially several causes. A leading consideration for the cause of narcolepsy type 1 is that it is an autoimmune disorder. Proposed pathophysiology as an autoimmune disease suggest antigen presentation by DQ0602 to specific CD4+ T cells resulting in CD8+ T-cell activation and consequent injury to orexin producing neurons. Relative risk for narcolepsy in a first-degree relative is considered to be at least 10 times higher than the general population, Having multiple relatives with a primary sleep disorder significantly increases the relative risk but absolute risk still remains low due to the rarity of the condition. The autoimmune process is thought to be triggered in genetically susceptible individuals by an immune-provoking experience, such as...