Causes and Risks:

The exact cause of narcolepsy is unknown. Research studies have indicated that the disorder may be genetic, with studies showing gene markers that may indicate a tendency to develop narcolepsy. The cause is a problem with the sleep-wake mechanisms in the brain.

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 may occur while working or driving a vehicle, having a conversation, or in any sedentary or boring situation.

There is a brief period of sleep and the person awakens feeling refreshed. However, they may again become uncontrollably sleepy a short time later.

Narcolepsy may 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 persons with narcolepsy also have dream-like hallucinations in the transition between sleep and wakefulness.

Prevention: There is no known prevention for narcolepsy. Treatment may reduce the number of attacks. Avoid situations that aggravate the condition if prone to attacks of narcolepsy.

Symptoms:

• Drowsiness
• Difficult for a young adult to stay awake during classes or work
• A sudden, uncontrollable need to sleep during the day (hypersomnia)
  • May occur several times during a day
  • Usually after eating, but may occur at any time
  • 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)
  • May be associated with emotional reactions such as laughter, anger
  • May be similar in appearance to seizures
• Temporary inability to use muscles (sleep paralysis)
  • Usually occurs immediately upon awakening or 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.

The diagnosis is confirmed by sleep studies (polysomnogram).

Tests to rule out other disorders may include:

• Lab tests (variable, depending on the suspected cause)
• ECG, electrocardiography (heart monitor)
• Monitoring of breathing
• EEG, electroencephalography (brain wave monitoring)
• Recording of the amount of sleep,
• Recording of observed sleep cycle including episodes of REM sleep (rapid-eye-movement, the part of the cycle where dreaming occurs)

Treatment: There is no known cure for narcolepsy. Treatment is aimed at control of the symptoms.

Lifestyle adjustments and learning to cope with the emotional and other effects of the disorder may improve functioning in work and social activities. Planned naps and sleeping may help to regulate daytime sleep and reduce the number of unplanned, sudden sleep attacks.

Eat light or vegetarian meals during the day, avoid heavy meals prior to important activities because heavy meals often provoke an attack of narcolepsy. If possible, schedule a brief nap (10 to 15 minutes) after meals.

Prescription medications may be required for some persons, including stimulants (such as dextroamphetamine and methylphenidate). Modafinil has recently been found to be effective in maintaining wakefulness. Antidepressant medications such as imipramine may be helpful in reducing episodes of cataplexy, but they usually do not reduce the number of sleeping episodes.

Prognosis: Narcolepsy is a chronic, life-long condition. It is not a fatal illness, but it may be dangerous if episodes occur during driving, operating machinery, or similar activities. Narcolepsy is usually controllable with treatment.

Complications:

• Injuries, accidents if attacks occur during activities
• Impairment of functioning at work
• Impairment of social activities
• Side effects of medications used to treat the disorder (See the specific medication.)

Call for an appointment with your health care provider if symptoms of narcolepsy are present (to rule out other disorders).

Call for an appointment with your health care provider if narcolepsy does not respond to treatment, or if other symptoms develop.