Narcolepsy

Medical quality assurance by Dr. Albrecht Nonnenmacher, MD at February 23, 2016
StartDiseasesNarcolepsy

Narcolepsy is a chronic neurological disorder that affects approximately 3% of the adult American population. Sufferers experience symptoms such as excessive daytime sleepiness, disrupted sleep patterns, and cataplexy on a daily basis. While there are plenty of effective treatment methods, there is currently no known cure.

Contents

Definition & Facts

German physicians Fisher and Westphal first described the symptoms of narcolepsy in their journals in 1870. Ten years later, it was officially recognized as a disorder by Gélineau, a French doctor. He coined the term from the Greek words narke and lepsis, meaning "numbness" and "attack" respectively.

Symptoms typically appear between the ages of 7 and 25 years old, though in rare cases may show up in young children and older adults. It lasts the entire duration of the sufferer's life. Narcolepsy is known to be under-diagnosed. This may be attributed to the common perception that sleepiness is not a disease.

Symptoms & Complaints

Patients that have narcolepsy experience its symptoms on a daily basis. In most cases, symptoms greatly impact the quality of life for sufferers. It is most akin to having constant and severe sleep deprivation. Common effects of narcolepsy are as follows:

Not all sufferers have all symptoms. Only about 10% to 15% of narcoleptics experience four or more of the above. Some of these symptoms could also be indicative of other disorders or diseases. In addition, disturbances caused by narcolepsy can lead to other medical conditions such as anxiety and depression.

Sufferers may begin to avoid social situations and common errands like shopping. Because of sleep attacks, driving or operating machinery become too dangerous a risk. Professional and personal relationships can suffer, leading to conflict and isolation.

Causes

Researchers have found that low levels of hypocretin may be the cause of narcoleptic symptoms. Hypocretin is a protein responsible for regulating sleep cycles and appetite. Antibodies in the brains of narcoleptics kill neurons that produce this critical hypocretin protein. For this reason narcolepsy is considered a neurological autoimmune disease. Due to the loss of hypocretin, the part of the brain that controls the sleep-wake cycle is disrupted.

Narcolepsy is typically the result of abnormal genetic conditions, especially related to the HLA complex. In some cases, however, the disease is caused by exposure to harmful chemicals such as pesticides at a young age. In other cases, previous infection, poor diets, and brain injuries may have caused low hypocretin levels and subsequent narcoleptic symptoms.

In one study, an H1N1 influenza vaccine was proven to triple the risk of the disorder in people below the age of 20. In addition, there is a strong correlation between the onset of narcolepsy and the seasons in which respiratory illnesses rise. Although the cause is not yet fully known, experts suspect that a combination of the factors above is responsible for the symptoms.

Diagnosis & Tests

To be diagnosed with narcolepsy, one typically goes to a sleep specialist to be tested. Tests range from polysomnograms to questionnaires such as the Epworth Sleepiness Scale. Polysomnograms require recordings of the patient's sleep. Recordings are analyzed for brain wave patterns as well as nerve activity and muscle activity. The Epworth Sleepiness Scale, however, consists only of 8 brief questions. The patient indicates how likely they are to fall asleep in different situations. The score then helps the doctor determine their likelihood of having a sleep disorder.

Multiple sleep latency tests are another test commonly used to diagnose those with sleep problems. These require the patient to sleep every 2 hours during the day after 8 hours of nighttime sleep. The time it takes for the patient to reach REM sleep is recorded. Patients who reach REM sleep quickly are more likely to be narcoleptic.

In addition to these methods of diagnosis, recent research has shown promise in detecting sleep disorders based on hypocretin levels found in cerebrospinal fluid. If levels of this protein are low, it is a strong indication of narcolepsy. Lumbar punctures, or spinal taps, are a safe and easy method of sampling spinal fluid for medical tests.

Treatment & Therapy

There is no known cure for narcolepsy, but there are a variety of treatments that have proven effective for patients. Prevailing treatments center around oral medication, but also include major lifestyle changes. Doctors prescribe medicines that stimulate the central nervous system. Methylphenidate, modafinil, dextroamphetamine, armodafinil, and amphetamine are common medications used to treat symptoms. Some medications like atomoxetine and antidepressants are used for patients at higher risk of addiction to standard treatments. Sodium oxybate has also been used to manage narcolepsy, and it carries no risk for addiction.

In addition to medication, patients are encouraged to exercise regularly, schedule naps and light meals, join a support group, and maintain a routine schedule for best results. It should be noted that naps alone are not an effective method to manage narcolepsy, and should only be used in conjunction with other treatments.

Patients should also avoid drugs like alcohol, caffeine, and nicotine. Results vary, but in many cases treatment substantially benefits the patient. Each person will have different methods of alleviating their symptoms due to differences in biology and response to therapy. Fortunately for most patients, the disease's effects on personal and professional lives diminish greatly with treatment.

Prevention & Prophylaxis

There is currently no known way to prevent narcolepsy. However, there have been some links between toxic chemicals and narcolepsy. Doctors advise that children not be exposed to pesticides, household cleaning products, and dangerous fumes. General health and safety precautions may decrease the risk of brain injury or respiratory illness that could cause sleep disorders. Otherwise, because it is primarily a genetic condition, there is little to be done to prevent narcolepsy.