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Definition  

Narcolepsy is a disorder of the nervous system. It results in frequent, involuntary, episodes of sleep during the day. Sleep attacks can occur while you drive, talk, or work.

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Causes  

The cause is unknown. It is thought to have a genetic link. There is increasing evidence that it may be an autoimmune disorder. In this type of disorder the body’s own immune system attacks a part of the brain.

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Risk Factors  

A risk factor is having family members with narcolepsy.

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Brainstem—Area of Brain Related to Alertness  
GM00010_97870_brainstem.jpg

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Symptoms  

Symptoms usually start during the teenage years. Onset may range from 5-50 years old. Symptoms may worsen with aging. They may improve in women after menopause .

Symptoms include:

  • Excessive daytime sleepiness
  • Daytime involuntary sleep attacks
  • Unrefreshing sleep
  • Sudden loss of muscle tone without loss of consciousness (cataplexy)
  • Temporary paralysis while awakening
  • Frightening mental images that appear as one falls asleep
  • Memory problems
  • Symptoms may be triggered by:
    • A monotonous environment
    • A warm environment
    • Eating a large meal
    • Strong emotions
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Diagnosis  

The doctor will ask about your symptoms and medical history. A physical exam will be done. If narcolepsy is suspected, you may be referred to a specialist in sleep disorders.

Tests may include:

  • Multiple sleep latency test (MSLT)—measures the onset of rapid eye movement sleep, which occurs earlier than normal in narcolepsy
  • General sleep lab study—often done the night before an MSLT; helps to rule out other causes of daytime sleepiness by monitoring:
    • Brain waves
    • Eye movements
    • Muscle activity
    • Respiration
    • Heart beat
    • Blood oxygen levels
    • Total nighttime sleep
    • Amount of nighttime REM sleep
    • Time of onset of REM sleep
    • Degree of daytime sleepiness
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Treatment  

Treatment may include:

  • Stimulant medicines that increase levels of daytime alertness, such as:
    • Methylphenidate
    • Dextroamphetamine
    • Methamphetamine
    • Modafinil
    • Armodafinil
    • Gamma-hydroxybutyrate (GHB)—for excessive daytime sleepiness and cataplexy, such as sodium oxybate
  • Antidepressants—to help treat many symptoms of narcolepsy (eg, cataplexy, hallucinations, sleep paralysis)

Other treatment options include:

  • Planned