Daytime sleep disorder
Key points
- Narcolepsy is a sleep disorder associated with uncontrollable sleepiness and frequent daytime sleeping.
- Studies using gene markers have indicated that the disorder may be genetic.
- Signs and tests Examination and testing are used to rule out disorders that may cause similar symptoms, including sleepiness that results from seizures, sleep apnea, insomnia, restless leg syndrome, or other sleep disorders.
- Lifestyle adjustments and learning to cope with the emotional and other effects of the disorder may improve functioning in work and social activities.
Alternative names
Narcolepsy
Definition
Narcolepsy is a sleep disorder associated with uncontrollable sleepiness and frequent daytime sleeping.
Causes, incidence, and risk factors
The exact cause of narcolepsy is unknown. Studies using gene markers have indicated that the disorder may be genetic. A small group of neurons in the brain has been implicated in producing transitions from sleep to wakefulness and vice-versa. People with narcolepsy may have fewer of these neurons or they may have been damaged.
The condition may be aggravated by conditions that cause insomnia, such as disruption of work schedules.
Narcolepsy is characterized by episodes of frequent, uncontrollable daytime sleeping, usually preceded by drowsiness. The episodes usually occur after meals, but sudden onset of sleep may occur while working or driving a vehicle, having a conversation, or being in any sedentary or nonstimulating situation.
There is a brief period of sleep, and the person awakens feeling refreshed. However, the person may again become uncontrollably sleepy a short time later.
Narcolepsy may also be associated with cataplexy, a brief episode of severe loss of tone of various muscles. Generalized weakness may occur for a few moments during the transition between sleep and wake (sleep paralysis). Many people with narcolepsy also have dreamlike hallucinations in the transition between sleep and wakefulness.
Symptoms
- Persistent drowsiness
- Difficulty for a young adult to stay awake during classes or work
- A sudden, uncontrollable need to sleep during the day (hypersomnia)
o May occur several times during a day
o Usually happens after eating, but may occur at any time
o Each sleep episode lasts about 15 minutes - Awake and refreshed feeling after each episode
- Hallucinations, visual (sight) or auditory (hearing) may precede sleep or occur during the sleep episode
- Sudden loss of muscle tone (cataplexy)
o May be associated with emotional reactions such as laughter or anger
o May be similar in appearance to seizures - Temporary inability to use muscles (sleep paralysis)
o Occurs immediately upon awakening
o Occurs at the onset of drowsiness
Signs and tests
Examination and testing are used to rule out disorders that may cause similar symptoms, including sleepiness that results from seizures, sleep apnea, insomnia, restless leg syndrome, or other sleep disorders.
Written and revised by
Gerald Hurowitz, M.D.
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