Narcolepsy in children: a practical guide to its diagnosis, treatment and follow-up

Allergies and Disease Severity in Childhood Narcolepsy: Preliminary Findings

INTRODUCTION

Narcolepsy frequently begins in childhood, and is characterized by excessive daytime sleepiness, with the presence of cataplexy reflecting a more severe phenotype. Narcolepsy may result from genetic predisposition involving deregulation of immune pathways, particularly involving T helper 2 cells (Th2). Increased activation of Th2 cells is usually manifested as allergic conditions such as rhinitis, atopic dermatitis, and asthma. We hypothesized that the presence of allergic conditions indicative of increased Th2 balance may dampen the severity of the phenotype in children with narcolepsy.

METHODS

A retrospective chart review of childhood narcolepsy patients was conducted at three major pediatric sleep centers. Patients were divided into those with narcolepsy without cataplexy (NC-) and narcolepsy with cataplexy (NC+). Demographics, polysomnographic and multiple sleep latency test data, and extraction of information on the presence of allergic diseases such allergic rhinitis, atopic dermatitis, and asthma was performed.

RESULTS

There were 468 children identified, with 193 children in NC- group and 275 patients in the NC+ group. Overall, NC+ children were significantly younger, had higher body mass index, and had shorter mean sleep latencies and increased sleep onset rapid eye movement events. The frequency of allergic conditions, particularly asthma and allergic rhinitis, was markedly lower in NC+ (58/275) compared to NC- patients (94/193; P < 0.0001).

CONCLUSION

Involvement of the immune system plays an important role in the pathophysiology of narcolepsy. Current findings further suggest that an increased shift toward T helper 2 cells, as indicated by the presence of allergic conditions, may modulate the severity of the phenotype in childhood narcolepsy, and reduce the prevalence of cataplexy in these patients.

Cataplectic facies: clinical marker in the diagnosis of childhood narcolepsy-report of two cases

BACKGROUND

Narcolepsy is a chronic disease and is commonly diagnosed in adulthood. However, more than half of the patients have onset of symptoms in childhood and/or adolescence. The full spectrum of clinical manifestations, namely excessive daytime sleepiness, cataplexy, hypnagogic hallucinations, and sleep paralysis, is usually not present at disease onset, delaying diagnosis during childhood. Mean delay in diagnosis since symptom onset is known to be several years. Initial manifestations can sometimes be as subtle as only partial drooping of eyelids leading to confusion with a myasthenic condition.

PATIENTS

We present two children who presented with "cataplectic facies," an unusual facial feature only recently described in children with narcolepsy with cataplexy.

RESULT

The diagnosis of narcolepsy was confirmed by multiple sleep latency test along with human leukocyte antigen typing and cerebrospinal fluid hypocretin assay.

CONCLUSION

The diagnosis of narcolepsy with cataplexy at onset can be challenging in young children. With more awareness of subtle signs such as cataplectic facies, earlier diagnosis is possible. To date, only 11 children between 6 and 18 years of age presenting with typical cataplectic facies have been reported in the literature. We present two patients, one of whom is the youngest individual (4 years old) yet described with the typical cataplectic facies.

High prevalence of precocious puberty and obesity in childhood narcolepsy with cataplexy

STUDY OBJECTIVES

We analyzed the potential predictive factors for precocious puberty, observed in some cases of childhood narcolepsy with cataplexy (NC) and for obesity, a much more common feature of NC, through a systematic assessment of pubertal staging, body mass index (BMI), and metabolic/endocrine biochemical analyses.

DESIGN

Cross-sectional on consecutive recruitment.

SETTING

Hospital sleep center and pediatric unit.

PATIENTS

Forty-three children and adolescents with NC versus 52 age-matched obese children as controls.

INTERVENTIONS

N/A.

MEASUREMENTS AND RESULTS

Patients underwent clinical interview, polysomnographic recordings, cerebrospinal fluid hypocretin-1 measurement, and human leukocyte antigen typing. Height, weight, arterial blood pressure, and Tanner pubertal stage were evaluated. Plasma lipid and glucose profiles were analyzed. When an altered pubertal development was clinically suspected, plasma concentrations of hypothalamic-pituitary-gonadal axis hormones were determined. Children with NC showed a high prevalence of overweight/obesity (74%) and a higher occurrence of precocious puberty (17%) than obese controls (1.9%). Isolated signs of accelerated pubertal development (thelarche, pubic hair, advanced bone age) were also present (41%). Precocious puberty was significantly predicted by a younger age at first NC symptom onset but not by overweight/obesity or other factors. In addition, overweight/obesity was predicted by younger age at diagnosis; additional predictors were found for overweight/obesity (short disease duration, younger age at weight gain and lower high-density lipoprotein cholesterol), which did not include precocious puberty. NC symptoms, pubertal signs appearance, and body weight gain developed in close temporal sequence.

CONCLUSIONS

NC occurring during prepubertal age is frequently accompanied by precocious puberty and overweight/obesity, suggesting an extended hypothalamic dysfunction. The severity of these comorbidities and the potential related risks require a multidiagnostic approach and a tailored therapeutic management.

Diagnosis and treatment of sleep disorders: a brief review for clinicians

Sleep disorders encompass a wide spectrum of diseases with significant individual health consequences and high economic costs to society. To facilitate the diagnosis and treatment of sleep disorders, this review provides a framework using the International Classification of Sleep Disorders, Primary and secondary insomnia are differentiated, and pharmacological and nonpharmacological treatments are discussed. Common circadian rhythm disorders are described in conjunction with interventions, including chronotherapy and light therapy. The diagnosis and treatment of restless legs syndrome/periodic limb movement disorder is addressed. Attention is focused on obstructive sleep apnea and upper airway resistance syndrome, and their treatment. The constellation of symptoms and findings in narcolepsy are reviewed together with diagnostic testing and therapy, Parasomnias, including sleep terrors, somnambulism, and rapid eye movement (REM) behavior sleep disorders are described, together with associated laboratory testing results and treatment.

Sodium oxybate in the treatment of childhood narcolepsy-cataplexy: a retrospective study

OBJECTIVE

To evaluate the efficacy and side effect profile of sodium oxybate in the treatment for narcolepsy-cataplexy in the pediatric age group.

METHODS

A retrospective study was conducted on 15 children and adolescents with narcolepsy-cataplexy who had been treated with sodium oxybate. The mean age at diagnosis of narcolepsy was 11 years (range 3-17 years). Subjects were followed for 3-90 months (mean 33) after starting sodium oxybate. During this period of time they were also maintained on other medications for sleepiness (n=14) and cataplexy (n=6). The charts were reviewed for documentation of improvement in sleepiness or cataplexy, side effects, and functioning in daily life.

RESULTS

Subsequent to the addition of sodium oxybate, sleepiness improved in 13/15 patients. In patients who had Epworth Sleepiness Scale (ESS) assessments, the score fell from a baseline median of 18 to 12 (n=10, p=0.01). The number of cataplexy episodes estimated by parents decreased from a median of 38/week pre-treatment to <1/week post treatment (n=14, p<0.001). Cataplexy severity, measured on an arbitrary scale, fell from a median of 3 (severe) to 1 (mild) in all 15 subjects (p<0.001). Two of the 15 patients (13%) discontinued sodium oxybate, one for insurance reasons and the other due to constipation and dissociative feelings. A third patient stopped the medication temporarily due to body aches and dizziness, but then resumed treatment without recurrence of symptoms. Side effects in four others included tremor, blurring of vision, nocturnal awakenings, and increased nightmares. Overall, side effects occurred in 6/15 (40%) individuals. Improvement in social/academic spheres was noted in 11/15 (73%) subjects after starting sodium oxybate. The median BMI before and after treatment remained unchanged at 23 (n=14, p=0.99). Median values of height and weight before and after treatment also did not change significantly. The mean dose of sodium oxybate was 5 ± 2 g. Dose escalation owing to development of tolerance was not encountered.

CONCLUSIONS

Sodium oxybate is effective in alleviating sleepiness and cataplexy in childhood onset narcolepsy-cataplexy. The therapeutic response was sustained over time, and without development of tolerance. Forty percent of the subjects experienced adverse effects.

Clinical and therapeutic aspects of childhood narcolepsy-cataplexy: a retrospective study of 51 children

STUDY OBJECTIVE

to report on symptoms and therapies used in childhood narcolepsy-cataplexy.

DESIGN, PATIENTS, AND SETTING

retrospective series of 51 children who completed the Stanford Sleep Inventory. HLA-DQB1*0602 typing (all tested, and 100% positive), polysomnography or Multiple Sleep Latency Test (76%), and cerebrospinal fluid hypocretin-1 measurements (26%, all with low levels) were also conducted. Prospective data on medication response was collected in 78% using a specially designed questionnaire.

MEASUREMENTS AND RESULTS

patients were separated into children with onset of narcolepsy prior to (53%), around (29%), and after (18%) puberty. None of the children had secondary narcolepsy. Clinical features were similar across puberty groups, except for sleep paralysis, which increased in frequency with age. Common features included excessive weight gain (84% ≥ 4 kg within 6 months of onset of narcolepsy) and earlier puberty (when compared with family members), notably in subjects who gained the most weight. Streptococcus-positive throat infections were reported in 20% of cases within 6 months of onset of narcolepsy. Polysomnographic features were similar across groups, but 3 prepubertal children did not meet Multiple Sleep Latency Test diagnostic criteria. Regarding treatment, the most used and continued medications were modafinil (84% continued), sodium oxybate (79%), and venlafaxine (68%). Drugs such as methylphenidate, tricyclic antidepressants, or selective serotonin reuptake inhibitors were often tried but rarely continued. Modafinil was reported to be effective for treating sleepiness, venlafaxine for cataplexy, and sodium oxybate for all symptoms, across all puberty groups. At the conclusion of the study, half of children with prepubertal onset of narcolepsy were treated "off label" with sodium oxybate alone or with the addition of one other compound. In older children, however, most patients needed more than 2 drugs.

CONCLUSION

this study reports on the clinical features of childhood narcolepsy and documents the safe use of treatments commonly used in adults in young children.

Sleep physiology and sleep disorders in childhood

Sleep has long been considered as a passive phenomenon, but it is now clear that it is a period of intense brain activity involving higher cortical functions. Overall, sleep affects every aspect of a child's development, particularly higher cognitive functions. Sleep concerns are ranked as the fifth leading concern of parents. Close to one third of all children suffer from sleep disorders, the prevalence of which is increased in certain pediatric populations, such as children with special needs, children with psychiatric or medical diagnoses and children with autism or pervasive developmental disorders. The paper reviews sleep physiology and the impact, classification, and management of sleep disorders in the pediatric age group.

Pediatric sleep pharmacology

This article reviews the most common pharmacologic options in the treatment of sleep disorders in children. Despite the high prevalence of sleep disorders in children, there is a paucity of education and information available on the pharmacologic management of sleep disorders in children. The principles of sleep physiology and pathophysiology that help provide more rational pharmacologic management are discussed. Medications are typically not Food and Drug Administration (FDA) approved for the pediatric age range or for the specific sleep disorder. Medications have a role for insomnia, narcolepsy, parasomnias, and sleep-related movement disorders. The available choices of hypnotics are reviewed. Medications to increase alertness of narcoleptics and decrease cataplexy are discussed. The use of dopaminergic agents for Restless Legs Syndrome is reviewed. The potential use of medication in sleep apnea is also reviewed. Pharmacologic guidelines need to be developed specifically for sleep disorders in children. Ideally, these guidelines should be FDA approved for the specific sleep disorder and for the pediatric age range. The development of easy to swallow, chewable or liquid forms of these medications are needed. Training programs should play the lead role in enhancing pediatricians' knowledge of the pharmacologic treatment of sleep disorders in children.

A Review of Pediatric Nonrespiratory Sleep Disorders

Sleep problems are extremely common during childhood, from infancy to adolescence. Despite the prevalence of sleep problems, childhood sleep disorders are often underrecognized and undiagnosed, despite being either preventable or treatable. Sleep impacts almost all aspects of a child's functioning, and thus the increased recognition and treatment of sleep disorders will positively affect a child's well-being. Children experience the same broad range of sleep disturbances encountered in adults, including sleep apnea, insomnia, parasomnia, delayed sleep phase, narcolepsy, and restless legs, but their clinical presentation, evaluation, and management may differ. Although snoring and sleep apnea may be the most common indication for an overnight sleep study in a child, one quarter of children presenting to a sleep clinic for evaluation will have a second sleep diagnosis, which is often nonrespiratory in nature. Especially in children, ruling out sleep apnea is rarely the end point of the sleep evaluation. Clinicians involved in sleep medicine must be prepared to recognize, evaluate, and manage plans for sleep disorders across the lifespan of the patient. This article will provide an updated review of nonrespiratory pediatric sleep disorders within a developmental framework.

Emerging drugs for narcolepsy

Narcolepsy is characterised by excessive daytime sleepiness, usually associated with cataplexy, hypnagogic hallucinations, sleep paralysis and fragmented nocturnal sleep. Although uncommon, it results in significant disability. Most cases occur sporadically, but genetic factors probably form a susceptibility background on which unknown environmental triggers act. The hypocretin system is strongly implicated in the development of narcolepsy. Cerebrospinal fluid levels of hypocretin-1 are significantly reduced in narcoleptic subjects with cataplexy. Despite the advances in our understanding of narcolepsy, current therapy is primarily symptomatic. Stimulants (standard and novel) combat excessive daytime sleepiness. Antidepressants (tricyclics, dual-action or selective serotonin re-uptake inhibitors) and sodium oxybate are anticataplexy agents. Hypnagogic hallucinations and sleep paralysis respond to antidepressants. Sodium oxybate consolidates sleep. Novel and experimental treatments include histamine antagonists, hypocretin agonists, slow-wave sleep enhancers, intravenous gamma-globulin, tramadol and corticosteroids.

Sleep disorders in children

PURPOSE OF REVIEW

Childhood sleep disorders are one of the most prevalent complaints in the pediatrician's office. Infant sleep rhythm complaints from new mothers reach 46%, while childhood obstructive sleep apnea has a prevalence of 2% and adolescent insomnia with daily consequences surpasses that percentage.

RECENT FINDINGS

Each sleep disorder must be considered in context of age, as age influences the presentation and impact on the developing child or adolescent. For example, sleep-disordered breathing resulting in adult sleepiness can contribute to death in infants. The symptoms of narcolepsy are often masked until after adolescence, resulting in psychologically costly misdiagnoses.

SUMMARY

There are no outcome studies that track the long-term consequences of pediatric sleep disorders or their contribution to adult sleep problems, but this is an area of increasing research interest. This review assesses the most recent literature on pediatric sleep disorders from May 1, 2002, until April 30, 2003.

Medication for sleep-wake disorders

Medication is indicated for only a limited number of children's sleep disorders. However, correctly chosen and supervised, pharmacological treatment may be justified and helpful. For a given sleep problem it is important to identify the underlying cause (or sleep disorder) which often calls for treatment of a non-medication type. Where medication is appropriate, cautious use and careful review of the child's physical and psychological state is essential in view of the limited information available on effectiveness and possible short and long term effects. It follows that much further research is required to establish the part medication can play in the care of children with sleep disorders, and also to define the possible effects on sleep and wakefulness of other drugs used in clinical practice.

Paediatric narcolepsy: complexities of diagnosis

Narcolepsy is a sleep disorder that is characterized by excessive daytime sleepiness and the inappropriate intrusion of aspects of rapid eye movement sleep into wakefulness. While the disorder emerges from an interplay of genetic and environmental factors, recent findings suggest that abnormalities in the neurotransmission of hypocretin may be implicated in its pathogenesis. Although narcolepsy has typically been associated with adulthood, there is a growing evidence base for the emergence of the disorder in childhood. We report suspected narcolepsy in early infancy, highlighting both the complexities of presentation and subsequent diagnosis associated with paediatric narcolepsy, and the significant psychosocial difficulties experienced by children and families managing this disorder.

Benefits and risks of pharmacotherapy for narcolepsy

Narcolepsy is a life-long central nervous system (CNS) syndrome characterised by excessive sleepiness, cataplexy, sleep paralysis, hypnagogic hallucinations and disturbed night-time sleep. Unsuccessfully treated narcolepsy confers increased risks on patients and on society due to the patient's increased chance of becoming involved in vehicle crashes and workplace mishaps. The syndrome may be diagnosed by a clinical history positive for cataplexy and excessive daytime sleepiness and negative for other more common sleep disorders such as sleep apnoea and sleep deprivation. Night-time polysomnography and multiple sleep latency testing are helpful in differentiating narcolepsy from other sleep problems. Recent data from canine, murine, and human forms of narcolepsy indicate that genetically or developmentally mediated deficits in the hypocretin neurotransmitter system may cause some, but not all, forms of narcolepsy. Pharmacotherapy for narcolepsy is required to control symptoms and involves the use of CNS stimulants or modafinil to control sleepiness and antidepressant medications or sodium oxybate to control cataplexy. Modafinil and sodium oxybate have been developed and approved specifically for the indication of narcolepsy based on large, double-blind, placebo-controlled, parallel group efficacy and safety studies. The efficacy of drugs in the treatment of narcolepsy is variable from patient to patient and usually associated with adverse effects that can limit patient compliance and, therefore, symptom control. Nevertheless, the benefits of pharmacotherapy are judged to outweigh the risks to the patient. The favourable benefit-risk ratio of pharmacotherapy is greater if one considers the reduced risk to society of vehicle crashes and workplace mishaps that might be precipitated by attentional lapses or sleep attacks in the untreated or under-treated patient with narcolepsy.

Schlafstörungen bei kinder- und jugendpsychiatrischen Erkrankungen

Zusammenfassung: Schlafstörungen als Symptom zahlreicher kinder- und jugendpsychiatrischer Störungsbilder komplizieren häufig den Verlauf und die Behandlung der Grunderkrankung. Organische Störungen wie die Narkolepsie oder das Kleine-Levin-Syndrom können zu differentialdiagnostischen Schwierigkeiten und Fehleinschätzungen führen. Unklar ist, ob spezifische Veränderungen der Schlafarchitektur bereits im Kindes- und Jugendalter bestehen und damit als biologischer Trait-Marker für psychiatrische Erkrankungen zu verstehen sind. Während für das Erwachsenenalter die Bedeutung von Schlafstörungen vor allem für die Entwicklung späterer depressiver Störungen belegt werden konnte, ist derzeit offen, ob es sich bei persistierenden Schlafstörungen im Kindesalter um Vulnerabilitätsmarker für psychiatrische Erkrankungen handelt. In der vorliegenden Literaturübersicht sollen Wechselwirkungen zwischen Schlafstörung und psychischer Störung aufgezeigt und die Bedeutung der Berücksichtigung von Schlafstörungen für Diagnostik und Therapie kinder- und jugendpsychiatrischer Störungsbilder unterstrichen werden.