$Unique_ID{BRK04038} $Pretitle{} $Title{Narcolepsy} $Subject{Narcolepsy Gelineau's Syndrome Paroxysmal Sleep Sleep Epilepsy Familial Periodic Paralysis Sleep Apnea } $Volume{} $Log{} Copyright (C) 1986, 1988, 1990, 1993 National Organization for Rare Disorders, Inc. 55: Narcolepsy ** IMPORTANT ** It is possible that the main title of the article (Narcolepsy) is not the name you expected. Please check the SYNONYMS listing to find the alternate name and disorder subdivisions covered by this article. Synonyms Gelineau's Syndrome Paroxysmal Sleep Sleep Epilepsy Information on the following diseases can be found in the Related Disorders section of this report: Familial Periodic Paralysis Sleep Apnea General Discussion ** REMINDER ** The Information contained in the Rare Disease Database is provided for educational purposes only. It should not be used for diagnostic or treatment purposes. If you wish to obtain more information about this disorder, please contact your personal physician and/or the agencies listed in the "Resources" section of this report. Narcolepsy is a rare disorder characterized by abnormal drowsiness during the day, sudden extreme muscle weakness (cataplexy), hallucinations, paralysis while sleeping, and disrupted sleep during the night. Symptoms The symptoms of Narcolepsy generally begin between the ages of 10 to 20 years. The development and severity of symptoms vary greatly from patient to patient. The onset of Narcolepsy symptoms initially occurs one at a time; appearance of new symptoms may be separated by years, and generally do not appear in any specific order. Narcolepsy usually begins in an adolescent whose initial symptoms are mild but become worse with age. Sometimes symptoms do not change for months or years, while at other times symptoms may change very quickly. Exaggerated daytime drowsiness is usually the first symptom of Narcolepsy. People with Narcolepsy usually experience periods of sleepiness, tiredness, lack of energy, an irresistible urge to sleep ("sleep attack"), and/or an inability to resist sleep. This susceptibility to unending drowsiness and/or falling asleep may occur every day but the severity varies throughout each day. The total sleep time for people with Narcolepsy in every 24 hour period is generally normal because they sleep repeatedly for short periods during the day and night. Another symptom of Narcolepsy is the sudden loss of voluntary muscle tone (cataplexy). This often occurs during times of intense emotions such as anger, elation, and/or surprise. Episodes of cataplexy may occur as short periods of partial muscle weakness. Occasionally, there may be an almost complete loss of muscle control that lasts for several minutes. This may result in sudden collapse. During a cataplectic attack, speech and movement become difficult or impossible although there is no loss of consciousness. People experiencing a cataplectic attack generally maintain partial awareness of their surroundings. Only some people with Narcolepsy will also have cataplexy, and cataplexy is not necessary for a diagnosis of Narcolepsy. Hallucinations are frightening episodes that may occur during the beginning and/or end of a sleep period (hypnaogic hallucinations) in people with Narcolepsy. Hallucinations may pertain to any or all of the senses (i.e., taste, touch, smell, hearing, and/or vision). These hallucinations may be so intense that it may be impossible for the person to distinguish reality from fantasy. People with Narcolepsy may experience "sleep paralysis." During sleep they may want to move but are unable to do so and as a result may experience panic. The occurrence of sleep paralysis typically coincides with falling asleep or waking up. People with Narcolepsy may awaken during the night as a result of nightmares, the urge to urinate, and/or temporary, repeated interruptions of breathing (sleep apnea). At times there is no apparent reason for awakening, and frequently the awakenings are associated with a craving for food, especially something sweet. (For more information on Sleep Apnea, see Related Disorders section of this report.) Causes The exact cause of Narcolepsy is not known. This disorder is known to run in families and an association with the human leukocyte antigen (HLA-DR2) has been reported in some cases of Narcolepsy. HLAs are genetic markers that have been identified on human chromosome 6. Scientists suspect that inheritance of a gene makes a person susceptible to Narcolepsy, but they do not know the pattern of inheritance and how the gene may be transferred from one generation to another. Affected Population The exact number of people with Narcolepsy in the United States is unknown. The American Narcolepsy Association has estimated that Narcolepsy affects approximately 200,000 Americans but other estimates are lower. Approximately 5 percent of people with Narcolepsy experience symptoms by the age of 10 years; 5 percent of patients have symptoms after the age of 20 years, and 18 percent of people with Narcolepsy develop symptoms after the age of 30 years. Symptoms rarely begin after the age 40. Narcolepsy tends to remain a lifelong condition. Slightly more males are affected by this disorder than females. Related Disorders Symptoms of the following disorders can be similar to those of Narcolepsy. Comparisons may be useful for a differential diagnosis: Symptoms resembling those of Narcolepsy may occur after brain tumors (intracranial), head trauma, hardening of the arteries in the brain (cerebral arteriosclerosis), psychosis, and/or excessive amounts of protein in the blood due to kidney failure (uremia). Episodes of sudden extreme muscle weakness (cataplexy) may also occur because of Familial Periodic Paralysis. This disorder is characterized by periods of cataplexy that last for prolonged periods of time as compared with cataplexy associated with Narcolepsy. Familial Periodic Paralysis is a result of an inborn error of potassium metabolism that causes abnormally high levels of this mineral in the blood. Sleep Apnea is a common sleep disorder characterized by temporary, recurrent interruptions of breathing during sleep. Symptoms of the disorder include wakefulness during the night, excessive sleepiness during the day, loud snoring, and/or obesity. In obstructive apnea, the most common form of Sleep Apnea, labored breathing is interrupted by airway tightening (constriction). The muscles of the diaphragm and chest build up sufficient pressure to force the airway open; partial awakening may then occur and the person may gasp for air. Sleep is resumed as breathing begins again. Untreated Sleep Apnea may be associated with high blood pressure, irregular heart beats, swelling in the arms and/or legs, hallucinations, anxiety, and/or irritability. (For more information on this disorder, choose "Apnea, Sleep" as your search term in the Rare Disease Database.) Therapies: Standard Diagnosis of Narcolepsy is made through sleep tests which monitor breathing, brain, and muscle activity throughout all the stages of sleep. A physician who is trained in sleep disorders is able to diagnose and treat Narcolepsy. There are several drugs that may help to control the symptoms of Narcolepsy. The medications selected for a particular patient are based on their symptoms and response to previous therapy. In some patients, Narcolepsy may be accompanied by repeated episodes of cataplexy while in other patients, sleep attacks are the most compelling symptoms. Those people who are not seriously hampered by sleep attacks, sleepiness, or cataplexy may not require drug therapy. Drugs used to treat people with Narcolepsy who experience sleep attacks and/or excessive sleepiness may include methamphetamines (such as Desoxyn) or amphetamines (such as Ritalin, Cylert, Dexedrine, or pemoline). Side effects of these drugs may include personality changes (particularly tenseness and irritability), and depression. These side effects typically occur in the late afternoon and evening as the drugs wear off, and/or on weekends when some individuals tend to reduce their drug dosage. Methylphenidate (Ritalin) is the preferred drug (a central nervous system stimulant) for the treatment of sleep attacks and drowsiness. Ritalin can be used together with other drugs used to treat cataplexy, whereas some other medications of this type can produce serious drug interactions. Drugs used to treat people with Narcolepsy who experience cataplexy include imipramine (tofranil), desipramine, protriptyline, and chlorimipramine. Some people with Narcolepsy may experience drug tolerance leading to a need for higher dosages which may increase the risks of side effects. Sudden withdrawal of these types of medications may result in exaggerated drowsiness, a dangerously severe depression, and/or a very dramatic increase of cataplectic symptoms. Close medical supervision by a physician is necessary for patients taking these drugs or withdrawing from them. Sleep habits are important for a person with Narcolepsy. Assuring regular bedtime hours and the prevention of sleep interruptions are important. Intervals of naps during the day may help to control excessive daytime sleepiness. A physician should help the patient in establishing a sleep schedule that is the most beneficial for the individual. Those Narcolepsy patients who also have sleep apnea will benefit from use of a device called a Continuous Positive Airway Pressure (CPAP). This medical device enables the patient to breathe normally during sleep so they are not deprived of oxygen and can achieve a more normal sleep pattern. Therapies: Investigational The National Institute of Mental Health (NIMH) and the National Institute of Neurological Disorders and Stroke (NINDS) support research in sleep disorders, including Narcolepsy. Gamma-hydroxybutyrate (GHB) is an orphan drug that is being tested in sleep disorder centers as a treatment for Narcolepsy and cataplexy. Fewer episodes of sleep paralysis and hynagogic hallucinations have been reported in some patients taking this drug. Preliminary studies indicate that some patients with Narcolepsy can stop or reduce their use of stimulant medications while taking gamma-hydroxybutyrate. The experimental drug is manufactured by Biocraft Laboratories, P.O. Box CN0200, Elmwood Park, New Jersey, 07407. Vitoxazine hydrochloride is another experimental drug currently being studied, especially for the control of cataplectic symptoms associated with Narcolepsy. For further information about this drug contact Stuart Pharmaceuticals, Division of ICI Americas, Inc., Wilmington, Delaware, 19897. Scientists are beginning to study human brain tissue from people with Narcolepsy. Preliminary reports suggest that the brains of people with Narcolepsy may have abnormally high numbers of specialized chemical sites (receptors) in their brain cells that bind to the neurotransmitter dopamine. These dopamine receptors are located deep within the brain in the basal ganglia, an area that regulates movement and emotions. This abnormality of dopamine receptors may be associated with the fact that emotional extremes can trigger attacks of cataplexy. More study of brain tissue is needed to confirm these findings. However, since people do not die of Narcolepsy, it is difficult for scientists to obtain enough postmortem brain tissue for study. This disease entry is based upon medical information available through June 1993. Since NORD's resources are limited, it is not possible to keep every entry in the Rare Disease Database completely current and accurate. Please check with the agencies listed in the Resources section for the most current information about this disorder. Resources For more information on Narcolepsy, please contact: National Organization for Rare Disorders (NORD) P.O. Box 8923 New Fairfield, CT 06812-1783 (203) 746-6518 American Narcolepsy Association, Inc. 425 California St. San Francisco, CA 94104 (415) 788-4793 Narcolepsy Network Box 1365, FDR Station New York, NY 10150 NIH/National Institute of Neurological Disorders & Stroke (NINDS) 9000 Rockville Pike Bethesda, MD 20892 (301) 496-5751 (800) 352-9424 References MENDELIAN INHERITANCE IN MAN, 10th Ed.: Victor A. McKusick, Editor: Johns Hopkins University Press, 1992. Pp. 752-753. CECIL TEXTBOOK OF MEDICINE, 19th Ed.: James B. Wyngaarden, and Lloyd H. Smith, Jr., Editors; W.B. Saunders Co., 1990. Pp. 2065-2066. BIRTH DEFECTS ENCYCLOPEDIA, Mary Louise Buyse, M.D., Editor-In-Chief; Blackwell Scientific Publications, 1990. Pp. 1214-1215. PRINCIPLES OF NEUROLOGY, 4th Ed.; Raymond D. Adams, M.D. and Maurice Victor, M.D., Editors; McGraw-Hill Information Services Company, 1989. Pp. 314-317. NARCOLEPSY UPDATE. J.W. Richardson et al.; Mayo Clin Proc (July 1990; 65(7)). Pp. 991-998. NARCOLEPSY. M.S. Aldrich; Neurology (July 1992; 42(7 Supp 6)). Pp. 34- 43.