Narcolepsy Sleep Disorder

What is Narcolepsy?

Narcolepsy is a sleep disorder with involuntary sleep episodes during usual waking hours. It is characterized by excessive daytime sleepiness, disturbed nighttime (nocturnal) sleep, and cataplexy (sudden weakness or loss of muscle tone without loss of consciousness). A chronic condition, narcolepsy can be mildly inconvenient or severely disabling. It often interferes with work and daily life. Hazardous activities, such as driving a car, become dangerous to self and others. Some individuals with narcolepsy also experience sleep paralysis, a sensation of being unable to move, and vivid, terrifying hallucinations (hypnagogic hallucinations). Both the paralysis and hallucinations occur at the onset of the sleep and upon awakening. The frequency of the cataplectic attacks varies greatly, from daily episodes to attacks occurring years apart. The attacks may last from a few seconds to more than an hour.

Narcolepsy affects over 100,000 people in the US. It is believed to have a genetic basis and can be exhibited in close relatives such as siblings. Men and women are affected equally. An extremely interesting finding is that in Caucasians and the Japanese, narcolepsy is 100% associated with the HLA-DR2 antigen detected in tissue typing. Though the symptoms can begin at any age, as a rule, narcolepsy has a gradual onset between the ages of 15 and 35 years and is fully established by age 25.

How is it diagnosed?

Signs and symptoms include excessive daytime drowsiness, recurring episodes of uncontrolled sleep during usual waking hours, vivid hallucinatory dreams at sleep onset, and sleep paralysis. Seventy-five to eighty percent of the individuals report cataplectic attacks. The family history is important as the first-degree relatives (parent and child, siblings) of known narcoleptics have at least a hundred-fold higher incidence of narcolepsy than the general population.

Physical exam: There are no physical findings associated with this disorder, aside from observing the individual during an actual episode of narcolepsy.

Tests: Testing at a sleep disorder clinic is the most accurate way to confirm a diagnosis of narcolepsy. The polysomnogram records the electroencephalogram (EEG - analyzes the electrical activity of the brain), the electroculogram (EOG - records the eye movements during sleep) and the electromyogram (EMG - records muscle activity). Rapid eye movement sleep (REM) is recorded by the EOG, and the multiple sleep latency test (MSLT) can distinguish the rapid onset of REM sleep seen in narcolepsy. REM sleep (sleep associated with dreaming) has a quicker onset in individuals with narcolepsy.

How is Narcolepsy treated?

Treatment is symptomatic. It usually involves stimulant drugs to control the drowsiness and sleep attacks. Treatment of cataplexy, hypnagogic hallucinations, and sleep paralysis requires tricyclic antidepressant drugs that are known to suppress REM activity. Structured daytime napping can be part of behavior modification used with drug therapy.

Medications for the treatment of narcolepsy

Information	Brand	Generic	Label	Rating
	Paxil	Paroxetine
	Effexor	Venlafaxine
	Zoloft	Sertraline

Prozac (Fluoxetine), Celexa (Citalopram), Tofranil (Imipramine), Ambien (Zolpidem)

Activity

• Don't engage in any activity that carries the risk of injury from a sudden sleep attack. These include activities such as driving long distances, climbing ladders or working around dangerous machinery.
• Exercise can sometimes decrease the number of sleep attacks. Seek to achieve optimal physical fitness.

What might complicate it?

Narcolepsy has physical and social ramifications that can be debilitating or life threatening.

Predicted outcome

Treatment is directed at controlling or lessening the sleep attacks and associated symptoms. Narcolepsy is a life-long condition that can be controlled in an individual who follows the treatment plans.

Alternatives

Atonic seizures are very similar to the cataplectic attacks of narcolepsy. They usually are associated with other seizures and the individual loses consciousness, unlike narcolepsy.

Appropriate specialists

Sleep disorder clinic and neurologist.

Last updated 20 December 2011