Narcolepsy

Narcolepsy is a chronic disorder of EDS. All patients experience EDS. Other symptoms include cataplexy, sleep paralysis, hypnagogic hallucinations, and disrupted nocturnal sleep. Treatment, usually with stimulants and low-doses of antidepressant medications, can dramatically improve the patient's quality of life. Although only advanced practice nurses may be actively involved in the diagnosis and treatment of this disorder, all nurses can encourage their patients who complain of EDS to consult a specialist in sleep disorders medicine, provide emotional support after diagnosis, and educate patients and their families about narcolepsy and its treatment.

Sleep disorders in children

Sleep disorders are common in childhood, and may affect multiple aspects of a child's life and the lives of other family members. A sleep disorder assessment should begin with detailed sleep history and a review of interrelated health issues. Factors contributing to disturbed sleep may be discovered or confirmed by a thorough physical examination. Thereafter, appropriate ancillary testing can provide support for a specific clinical diagnosis. The spectrum of childhood sleep disorders includes OSA, narcolepsy, RLS/PLMD, sleep onset association disorder, and parasomnias. Diagnosing sleep disorders in children remains a challenge; however, a multidisciplinary approach may provide an opportunity for productive collaboration and, thereby, more effective patient management. Centers treating pediatric sleep disorders may include providers from a variety of disciplines in pediatric healthcare, such as child psychology, pulmonology, neurology, psychiatry, nursing, and otolaryngology. Over the last decade, research in pediatric sleep disorders has expanded greatly, paralleled by an increased awareness of the importance of adequate, restorative sleep in childhood.

[Narcolepsy-cataplexy]

The diagnosis of narcolepsy-cataplexy is based on three axes: 1) the medical history is strongly suggestive when diurnal sleep attacks (narcolepsy) and drop attacks (cataplexy) are reported or observed; 2) the polysomnography is mandatory and shows nocturnal and diurnal (multiple sleep latency test) REM sleep onsets; 3) HLA typing, practically helps to exclude the diagnosis when HLA DR15-DQB1*0602 is not present. New pathogenetic hypotheses have been proposed, mostly based the absence of hypocretin in narcoleptic cerebrospinal fluid. This neurotransmitter was previously known exclusively by its involvement in alimentary behaviours. The new therapies remain symptomatic, but they are powerful to prevent somnolence, daytime sleepiness, cataplexy and insomnia associated with this syndrome.

Orexins: from neuropeptides to energy homeostasis and sleep/wake regulation

The neuropeptides orexin A and orexin B (also called hypocretin 1 and 2) were recently discovered by a "reverse pharmacology" approach as ligands for two previously orphan G protein coupled receptors: orexin receptors 1 and 2. Neurons producing orexins are located exclusively in the lateral hypothalamic area but project broadly to various parts of the brain, and they have been implicated in the control of energy homeostasis and arousal maintenance. The orexin receptors are also broadly expressed in the central nervous system. Murine and canine models suggest that defective signaling in the orexin system is responsible for the sleep/wake disorder narcolepsy. Although narcoleptic patients rarely have genetic defects in the orexin system, they lack these neuropeptides in the brain and cerebrospinal fluid, indicating that human narcolepsy is an orexin deficiency syndrome in the majority of cases. A connection between sleep/wake regulation and energy homeostasis is hypothesized with orexin neuropeptides as a molecular link.

Narcolepsy in children

Core symptoms of narcolepsy are similar in children compared with adults, but expression may be different due to more severe manifestations, maturational factors, and the significant impact of symptoms on behavior and academic performance. Diagnosis of narcolepsy in children is often challenging and requires a detailed history followed by polysomnography and the Multiple Sleep Latency Test. Management involves a comprehensive approach, including patient and family education and emotional support; behavioral strategies, such as good sleep hygiene and planned naps; and pharmacologic intervention. Despite dramatic progress recently in understanding the etiology of human narcolepsy through molecular genetic investigations, the disorder remains a chronic and often disabling disease with major impact on the lives of children and their families.

Narcolepsy and the HLA region

Narcolepsy was first shown to be tightly associated with HLA-DR2 and DQ1 in 1983, suggesting a possible autoimmune mechanism. Early investigations failed to demonstrate this hypothesis, postulating that HLA-DR2 was only a linkage marker for another, unknown narcolepsy-causing gene. The autoimmune hypothesis is now being re-evaluated under the light of recent results. Like many other autoimmune disorders, narcolepsy usually starts during adolescence, is human leukocyte antigen (HLA)-associated, multigenic and environmentally influenced. Furthermore, HLA-association studies indicated a primary HLA-DQ effect with complex HLA class II allele interactions and a partial contribution of HLA to overall genetic susceptibility. Finally, recent result suggests that human narcolepsy is associated with the destruction of a small number of hypothalamic neurons containing the peptide hypocretins (orexins). This data is consistent with an immune destruction of hypocretin-containing cells as the most common etiology for human narcolepsy.

Practice parameters for the treatment of narcolepsy: an update for 2000

Successful treatment of narcolepsy requires an accurate diagnosis to exclude patients with other sleep disorders, which have different treatments, and to avoid unnecessary complications of drug treatment. Treatment objectives should be tailored to individual circumstances. Modafinil, amphetamine, methamphetamine, dextroamphetamine, methylphenidate, selegiline, pemoline, tricyclic antidepressants, and fluoxetine are effective treatments for narcolepsy, but the quality of published clinical evidence supporting them varies. Scheduled naps can be beneficial to combat sleepiness, but naps seldom suffice as primary therapy. Regular follow up of patients with narcolepsy is necessary to educate patients and their families, monitor for complications of therapy and emergent of other sleep disorders, and help the patient adapt to the disease.

Narcolepsy in a 12-month-old-boy

Narcolepsy, although frequently beginning in childhood, is usually diagnosed in young adults. The diagnostic symptoms of narcolepsy are usually less typical in the young child, and sleep studies have not been standardized. We present a 12-month-old child with symptoms typical for narcolepsy who shows improvement with nonpharmacologic narcolepsy therapy.

Sleep disorders

Many pharmacologic and nonpharmacologic strategies are available to treat sleep disorders successfully. Conventional stimulants and the new stimulant modafinil have roles to play in the management of narcolepsy and idiopathic hypersomnia. Knowledge of the properties and clinical effects of these drugs allows adequate doses of medications to be used with the goal of attaining as maximal alertness as possible. A range of dopaminergic agents is available to treat restless legs syndrome; other medications such as opiates, benzodiazepines, and anticonvulsants can also be used. Successful use of the dopaminergic agents depends on an understanding of the phenomena of augmentation, rebound, and tolerance. Arousal parasomnias can be treated with behavioral methods such as hypnosis and drug therapy. Clonazepam provides relief of the symptoms in most patients with REM sleep behavior disorder.

Narcolepsy: new understanding of irresistible sleep

Recently, low levels of a newly identified neuropeptide, hypocretin 1, were described in the cerebrospinal fluid of patients with narcolepsy. This neurochemical finding furthers our understanding of this enigmatic sleep disorder typically characterized by excessive daytime sleepiness, cataplexy, sleep paralysis, and hypnagogic hallucinations. Narcolepsy appears to be fundamentally related to abnormally regulated rapid eye movement sleep. The diagnosis of this disorder remains challenging because of multiple other conditions that can cause daytime sleepiness and the difficulties in recognizing cataplexy based on patient report. The role of hypocretins in narcolepsy is unclear but intriguing because the cell bodies are restricted to the lateral hypothalamus, a brain region long associated with sleep regulation, with neuronal widespread projections to areas including the locus ceruleus, ventral tegmental area, amygdala, and dorsal raphe. Hypocretins potentially modulate the activity of monoamines and acetylcholine, and therefore their absence leads to the multiple symptoms of narcolepsy. This article reviews the current understanding of the diagnosis and treatment of narcolepsy and discusses the possible implications of the hypocretin discovery.

[Treatment of the neurological sleep disorders restless legs syndrome and narcolepsy]

Pharmacological therapies are presented for two typical neurological sleep-wake disorders, restless legs syndrome (RLS) and narcolepsy. The individual discomfort caused by RLS and the accompanying problems with initiating and maintaining sleep often require a therapy with L-dopa and dopamine agonists. Positive treatment effects on sensory and motor symptoms have been shown in open trials and controlled studies. Development of time shift and/or augmentation of symptoms is a problem of L-dopa therapy. Further efficient drugs are opioids and benzodiazepines. The therapy of narcolepsy depends on its severity and the pattern of the symptoms. Excessive daytime sleepiness and sleep attacks are the most impairing symptoms, which are difficult to treat. These symptoms require an optimal combination of CNS stimulants with regular napping. Cataplexy and other REM sleep associated symptoms are effectively treated with REM sleep suppressing antidepressants.

[New perspectives in the diagnosis and therapy of narcolepsy]

Narcolepsy syndrome is a common, although often misdiagnosed, neurological disorder, whose clinical features are excessive daytime somnolence with sleep attacks, caplexy, sleep paralysis and hypnagogic hallucinations. The clinical manifestation have been interpreted as the expression of a sudden intrusion of dissociated REM phenomena in wakefulness. Sometimes the clinical manifestations may include only some of the symptoms: in particular, the cases in which the only symptom is excessive daytime somnolence may be difficult to diagnose. The etiopathogenesis of narcolepsy syndrome is still poorly understood. Recent experimental evidences suggest that a protein, called "orexin", which is supposed to play a role in the control mechanisms of both sleep and eating behaviour, is involved in its pathogenesis. The treatment of narcolepsy has been, up to now, exclusively symptomatic, and in some way empirical and unsatisfactory, especially regarding to daytime sleepiness. Recently, new pharmacological agents, acting on the serotoninergic and/or noradrenergic systems, allow a better control of the cataplectic attacks. The recent development of modafinil, a central nervous system stimulant, devoid of the serious side effects of amphetamines and other compounds, allows to hope in a better control of daytime somnolence and sleep attacks. The aim of the paper is to describe the recent advances in the diagnosis and treatment of narcolepsy.

Narcolepsy and other causes of excessive daytime sleepiness

Narcolepsy is a chronic disorder characterized by excessive daytime sleepiness, cataplexy, and other auxiliary symptoms. An interview can ascertain specific symptomatology, whereas a polysomnogram can reveal distinct clinical features. The clinical and laboratory evaluation together enable an accurate diagnosis of narcolepsy. This diagnosis includes a wide spectrum of symptom combinations. Treatment of narcolepsy should include the empathic guidance of a sleep clinician, an emphasis on sleep hygiene, and in many cases pharmacotherapy.

[Sleep disorders--the problem with chrono-medicine]

The aim of this paper is to present the clinical symptomatology and the methods of the therapy in the main sleep disorders: insomnia, narcolepsy and parasomnias.

Sleep and its disorders

Sleep disorders are very prevalent in the general population and are associated with significant medical, psychological, and social disturbances. Insomnia is the most common. When chronic, it usually reflects psychological/behavioral disturbances. Most insomniacs can be evaluated in an office setting, and a multidimensional approach is recommended, including sleep hygiene measures, psychotherapy, and medication. The parasomnias, including sleepwalking, night terrors, and nightmares, have benign implications in childhood but often reflect psychopathology or significant stress in adolescents and adults and organicity in the elderly. Excessive daytime sleepiness is typically the most frequent complaint and often reflects organic dysfunction. Narcolepsy and idiopathic hypersomnia are chronic brain disorders with an onset at a young age, whereas sleep apnea is more common in middle age and is associated with obesity and cardiovascular problems. Therapeutic naps, medications, and supportive therapy are recommended for narcolepsy and hypersomnia; continuous positive airway pressure, weight loss, surgery, and oral devices are the common treatments for sleep apnea.

Narcolepsy. Signs, symptoms, differential diagnosis, and management

Narcolepsy is a chronic neurologic disorder characterized by excessive daytime sleepiness and cataplexy and less often by hypnagogic hallucinations and sleep paralysis. While patients report excessive daytime sleepiness and cataplexy as the more frequent symptoms of this condition, excessive daytime sleepiness is generally believed to be the most debilitating. Narcolepsy often is undiagnosed or misdiagnosed for a variety of reasons. Although confirmation of an initial diagnosis requires monitoring of physiologic variables conducted at a sleep center by specialists, the primary care physician has a critical role in the identification and management of this incurable affliction. This article provides recommendations for the diagnosis and management of narcolepsy. The cataplexy associated with narcolepsy can be managed with tricyclic antidepressants. The excessive sleepiness is managed with stimulants but newer agents, such as modafinil, which will be marketed as Provigil, and selegiline hydrochloride, with fewer adverse effects and less abuse potential, may offer means of promoting daytime wakefulness. Groups such as the National Sleep Foundation, Washington, DC, and the Narcolepsy Network, Cincinnati, Ohio, can provide patients with needed support and information.

[Narcolepsy in children--a diagnostic and therapeutic challenge]

Narcolepsy is a socially and psychologically disabling disease that most often develops in adolescence or early adulthood. In a number of studies about one-third of the patients had experienced the first symptoms before the age of 15. The diagnosis and subsequent treatment is usually not established until several years later, often ten to fifteen years after the appearance of the first symptoms. If unrecognized and untreated, narcolepsy may lead to serious psychological and social problems during childhood and early adulthood, which may in turn cause difficulties in social adjustment later in life. This stresses the importance of early diagnosis. The diagnosis is based on clinical and polysomnographic criteria. In children, however, the clinical symptoms and polysomnographic findings may be atypical, making it difficult to establish a definite diagnosis. Three patients, two five-year olds and one four and a half-year old, are presented to illustrate the problems and considerations which must be taken into account in the diagnosis and treatment of children with narcolepsy.