The following summary information about narcolepsy was kindly provided to us by the Narcolepsy Network USA. For more information on narcolepsy and support group please visit the Narcolepsy Network web-site.
It should be noted that because some of the symptoms of narcolepsy e.g. sleepiness, are common to many conditions, and it often coexists with other conditions, narcolepsy is a condition that can be difficult to diagnose. If you think you or a loved one may have narcolepsy contact your physician to discuss.
Question: What is narcolepsy?
Answer: Narcolepsy is a neurological sleep disorder that can begin at any age and continues throughout life. The onset typically occurs during the teens or early twenties but it can also appear later in life. Predisposition to it is partially hereditary. It is believed to affect approximately 1 in every 2000 people of both sexes and all races. Once fully established, narcolepsy is generally stable and can be most often effectively managed. People with narcolepsy can expect to live a normal life span.
Question: What causes narcolepsy?
Answer: Much has been learned since 1998, when researchers discovered the two brain chemicals called hypocretins (aka orexins). These neurotransmitters are involved in the regulation of the sleep/wake cycle as well as other bodily functions (e.g., blood pressure and metabolism). Research has shown that the majority of hypocretin-producing cells, located in the hypothalamus, have been destroyed in the brains of those who develop narcolepsy with cataplexy. In 2009 scientists definitely demonstrated that hypocretin-deficient narcolepsy is an auto-immune disorder. The cause(s) of narcolepsy without cataplexy are unknown. Further research is needed to determine why hypocretin cells are destroyed and to identify the exact trigger(s) of both forms of narcolepsy.
Question: What are the symptoms?
Answer: There are five primary symptoms:
- Excessive Daytime Sleepiness (EDS), which includes in its most severe form daytime “sleep attacks” that may occur with or without warning and which may be uncontrollable; persistent drowsiness, which may continue for prolonged periods of time; and micro sleeps, or fleeting moments of sleep, which may intrude into the waking state.
- Cataplexy, the second major symptom of narcolepsy, is a sudden loss of voluntary muscle control, usually triggered by emotions such as laughter, surprise, fear or anger. Cataplexy may occur more frequently during times of stress or fatigue. The cataplectic attack may involve only a slight feeling of weakness and limp muscles (i.e., sagging facial muscles, a nodding head, buckling knees, loss of arm strength, garbled speech), or less frequently it may result in immediate and total body collapse, during which the person may appear unconscious as he is non responsive, but is actually awake and alert. These attacks may last from a few seconds up to several minutes. Cataplectic episodes are related to the loss of muscle tone usually associated with the normal dreaming stage of sleep called rapid eye movement (REM); as a protection against acting out one’s dreams, the muscles become immobile or paralyzed.
- Disrupted or fragmented nighttime sleep, involves multiple periods of arousal and the experience of poor sleep quality.
The other two primary symptoms are:
- Hypnagogic hallucinations at sleep onset as well as – vivid, realistic, and often frightening dreams; and
- Sleep paralysis – a temporary inability to move. Either one or both of these can occur during the transition between sleep and wakefulness, while the brain is neither fully awake nor fully asleep and can occur simultaneously with hypnagogic hallucinations.
Question: Are there any other symptoms?
Answer: The following secondary or auxiliary symptoms may appear:
- Automatic behavior – the performance of a routine task, without conscious awareness of doing it, and often without later memory of it.
- Other – Side effects of the medications or problems resulting from a continual effort to cope with the symptoms may produce additional problems. Feelings of intense fatigue and continual lack of energy are often reported, and depression is not uncommon. The ability to concentrate and memorize may be compromised. Vision or focusing problems, or sleep eating or eating binges, may also occur. Alcohol may amplify or neutralize the effects of medications taken for the primary symptoms.
Question: How is a diagnosis of narcolepsy determined?
Answer: Excessive daytime sleepiness (EDS) is often the first symptom to appear, and, for many, the primary symptom of narcolepsy. However, EDS is also a symptom of various other medical conditions. Cataplexy, on the other hand, is unique to narcolepsy. The combination of EDS and cataplexy allow for a clinical diagnosis of narcolepsy. Even when cataplexy is present, laboratory tests are typically still being needed to confirm diagnosis and determine a treatment plan. The usual diagnostic procedure includes an overnight polysomnogram (PSG or sleep study) to rule out other causes of EDS and to determine the presence of unusual REM patterns. This is followed by the Multiple Sleep Latency Test (MSLT), or daytime nap test, which measures rapidity of sleep onset (measure of sleepiness) and how quickly REM sleep follows. The MSLT is the most widely accepted diagnostic test for narcolepsy. In addition, a genetic blood test has been developed which measures certain antigens often found in people who have a predisposition to narcolepsy. Positive results suggest a predisposition, but do not prove the presence of narcolepsy. This test is sometimes used when the diagnosis is in question. A new test is currently in use at a limited number of research facilities, which measures the level of hypocretin in cerebrospinal fluid (CSF). The absence of detectable hypocretins can confirm the presence of narcolepsy/cataplexy, but normal levels of hypocretin cannot rule out the disorder.
Question: How is narcolepsy treated?
Answer: The goal is to decrease EDS and reduce occurrences of cataplexy using minimal medication. EDS and cataplexy must be treated separately. Traditionally, central nervous system stimulants (i.e., Ritalin, Dexedrine, etc.) have been used for EDS. In 1999, Provigil (Modafinil) was the first stimulant approved for treatment of EDS associated with narcolepsy. Nuvigil, a longer-acting formulation of modafinil, has just been approved by the FDA. Tricyclic antidepressants (i.e., Vivactil, Tofranil, etc.) and serotonin reuptake inhibitors (SSRIs) have traditionally been used for treatment of cataplexy and other REM symptoms. Most recently, the antidepressants Effexor (an SSNRI), and Strattera (an SNRI), are showing excellent results in alleviating cataplexy and reducing other REM symptoms. In 2002, a new drug, Xyrem (sodium oxybate), was approved for the safe and effective treatment of cataplexy. In 2005, Xyrem was also approved to treat EDS associated with narcolepsy. Xyrem is the only medication that treats all major symptoms of narcolepsy.
In addition to drug therapy, short naps during the day may help control sleepiness and maintain alertness. Diet control, such as avoidance of sugar and refined carbohydrates, and regular exercise may also help. Continuing doctor-patient communication is essential. Equally important is educating family, friends, teachers, and co-workers about narcolepsy. Joining a support group is recommended.
Question: What research is being conducted?
Answer: Sleep scientists, at present, are focusing on genetics, neurotransmitters, and the autoimmune system. Researchers also believe that other factors, such as viral and bacterial agents, abrupt changes in wake-sleep cycles, illnesses, accidents, stressors, and even hormonal changes, may act as triggers, which determine whether or not someone with a genetic predisposition to narcolepsy will eventually develop the disorder.