Narcolepsy

Narcolepsy is often diagnosed in adolescence and young adulthood, when falling asleep suddenly in school brings the problem to attention. However, for many people with narcolepsy, the disorder is not diagnosed for up to 10-15 years after symptoms first begin. The disorder may be misdiagnosed as various other conditions or psychological problems. While it is most easily recognized if all the major symptoms are reported, making the diagnosis based solely on symptoms is difficult. People often seek medical help for single symptoms that could be associated with other disorders, particularly epilepsy. In come cases, symptoms are not dramatically apparent for years.

Sleep studies are an essential part of the evaluation of people with possible narcolepsy. The combination of an overnight polysomnogram (PSG) followed by a multiple sleep latency test (MSLT) can provide strongly suggestive evidence of narcolepsy, while excluding other sleep disorders. Measurement of hypocretin levels in the cerebrospinal fluid (CSF) may further help to establish the diagnosis. People with narcolepsy often have extremely low levels of hypocretin in their CSF. In some cases, human leukocyte antigen (HLA) typing may be helpful.

In most people with narcolepsy, symptoms first begin between the ages of 7 and 25. In rare cases, symptoms may begin at a younger age or in older adults. The disorder has been reported in children as young as 2 years of age.

The onset of symptoms initially occurs one at a time. The appearance of new symptoms can be separated by years. Sleepiness generally begins before cataplexy. Sometimes symptoms do not change for months, while at other times symptoms may change very quickly.

Seizures are not a symptom of narcolepsy. However, cataplexy may first be misdiagnosed as a seizure disorder. In about 10% of cases of narcolepsy, cataplexy is the first symptom to appear, which may lead to a misdiagnosis of epilepsy. Cataplexy is a sudden loss of muscle tone and control while a person is awake. Cataplectic attacks vary in length of time and severity. They may be barely perceptible (such as a momentary sense of slight weakness), or severe, resulting in a complete loss of tone in all voluntary muscles. This can lead to collapse, during which an affected person is unable to move, speak, or keep the eyes open. However, even during the most severe episodes, people remain fully conscious - this characteristic is what distinguishes cataplexy from seizure disorders. Additionally, some people with narcolepsy have so- called microsleep episodes, in which they behave automatically without conscious awareness. During these episodes, a person's behavior may resemble some forms of epileptic seizures. Narcolepsy can easily be mistaken for epilepsy, so ruling out epilepsy is an important part of making a diagnosis of narcolepsy.

Seizures may be a very serious side effect of the drug sodium oxybate, one of the main drug treatments for narcolepsy. This drug is used to treat cataplexy. Seizures, coma and death have been reported in people who abused this drug; however, trials have not reported these effects with the doses used in treatment for cataplexy.

There is currently no cure for narcolepsy, but some of the symptoms can be managed with medications and lifestyle changes.

Most affected people improve if they maintain a regular sleep schedule, usually 7.5 to 8 hours of sleep per night. Scheduled naps during the day also may help. Other measures that may help include participating in an exercise program; receiving emotional support and career or vocational counseling; and avoiding high-risk behaviors such as alcohol and drug use, which may make symptoms worse. Common-sense measures should be taken to enhance sleep quality (such as avoiding heavy meals before bed time).

Treatment with medications involves the use of central nervous system (CNS) stimulants. These medications help reduce daytime sleepiness and improve this symptom in 65-85% of affected people. Two types of antidepressant drugs (tricyclics, and selective serotonin and noradrenergic reuptake inhibitors) are effective in controlling cataplexy in many people. Sodium oxybate (a strong sedative taken during the night) may also be used to treat narcolepsy.

You can view detailed information about the treatment of narcolepsy on Medscape's Web site.