139 Coelho FMS, Aloe F, Moreira G, Sander HH, Roitman I, Prado LF, et al. Sleep Sci. 2012;5(4):139-144 Narcolepsy in childhood and adolescence REVIEW Narcolepsia na infância e na adolescência Fernando M. S. Coelho 1,2 , Flavio Aloe 5† ,Gustavo Moreira 1 , Heidi H. Sander 3 , Israel Roitman 1 , Lucila F. Prado 1 , Márcia Pradella-Hallinan 1 , Regina M. F. Fernandes 4 , Rosana S. C. Alves 3 Study carried out at Universidade Federal de São Paulo (UNIFESP), São Paulo (SP), Brazil. 1 Universidade Federal de São Paulo (UNIFESP), São Paulo (SP), Brazil. 2 Instituto Israelita de Ensino e Pesquisa do Hospital Israelita Albert Einstein, São Paulo (SP), Brazil. 3 Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo (FMUSP). 4 Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brazil. 5† In memorian. Corresponding author: Marcia Pradella-Hallinan. Rua Marselhesa, nº 500, 14º andar. Vila Clementino. São Paulo - SP. Brazil. CEP: 04020-060. Tel: 55 (11) 5908-7000. E-mail: marcia@psicobio.epm.br; marcia.phallinan@gmail.com Received: January 19, 2012; Accepted: April 19, 2012. Financial support: AFIP & FAPESP - CEPID 98/14303-3. ABSTRACT The present review article discusses the most important aspects of narcolepsy in children. The main objective of this review is to describe the clinical and laboratory characteristics of narcolepsy in patients within a targeted age range and to discuss hypotheses regarding the physiopathology of this disease. Excessive daytime sleepiness is reported by up to 20% of schoolchildren and ado- lescents. In 16% of these cases, narcolepsy begins before the age of 10 years, whereas 30% of narcoleptic patients exhibit its ini- tial symptoms during childhood. A delayed diagnosis might lead to severe, negative future consequences for the affected patients. Human narcolepsy is a complex disease. The association of HLA -DQB1*0602 with low hypocretin levels indicates a genetic suscep- tibility with an associated immune component. Narcolepsy is cha- racterized by excessive daytime sleepiness and cataplexy and might be associated with hypnagogic hallucinations, sleep paralysis, and sleep fragmentation. The diagnosis of narcolepsy depends on the clinical assessment and the performance of multiple sleep latency tests preceded by polysomnography. In children, the search for se- condary causes of narcolepsy is important because approximately 25% of these patients are symptomatic. The treatment of narco- lepsy in children is basically symptomatic, and most cases require behavioral and pharmacological approaches. New therapeutic mo- dalities which impede progression of the disease at the onset of symptoms have also been investigated. Keywords: adolescent, child, narcolepsy. RESUMO Este é um artigo de revisão que busca abordar os pontos mais im- portantes da narcolepsia em crianças. Os principais objetivos deste artigo são alertar os leitores sobre as principais características clíni- cas e laboratoriais dos pacientes com narcolepsia nesta faixa etária, além de discutir algumas hipóteses da fsiopatologia da doença. A queixa de sonolência excessiva diurna é referida em até 20% das crianças em idade escolar e adolescentes. A narcolepsia pode ini- ciar-se em 16% dos casos antes dos 10 anos de idade e 30% dos casos de narcolepsia apresentavam sintomas iniciais na infância. O atraso no diagnóstico pode levar a sérias repercussões negativas no futuro destes pacientes. A narcolepsia humana é uma doença com- plexa. A associação entre o antígeno HLA-DQB1*0602 e níveis reduzidos de hipocretina sugere uma suscetibilidade genética com componente imunológico associado. A narcolepsia se caracteriza por sonolência excessiva diurna e cataplexia, podendo ter associa- ção de alucinações hipnagógicas, paralisia do sono e fragmentação do sono. O diagnóstico depende do acompanhamento clínico e da realização do teste das latências múltiplas de sono precedido pela polissonografa. Na infância é importante a pesquisa de causas se- cundárias para a narcolepsia, uma vez que ao redor de 25% dos ca- sos pode ser sintomático. O tratamento da narcolepsia em crianças é atualmente essencialmente sintomático e, na maioria dos casos, exige a abordagem comportamental e farmacológica. Novas moda- lidades terapêuticas com bloqueio da evolução da doença no início dos sintomas têm sido estudadas. Descritores: adolescente, criança, narcolepsia. INTRODUCTION During the frst few years of life, episodes of daytime sleep may be considered normal, and most children will take routine naps until they are 3 years of age. In children and adults, excessive sleepi- ness (ES) is defned as the tendency to sleep (or the actual occur - rence of sleep) during the wakeful period, with a frequency or dura- tion that does not correspond to a given age range, prolonged night sleep, or the necessity of a greater number of night sleep hours (1-3) . ES complaints are presented by up to 20% of school-age children and adolescents (4) . Although narcolepsy is not often di- agnosed during the pediatric age range, the condition can begin before the age of 10 in 16% of the patients. Approximately 30% of narcoleptic patients exhibit initial symptoms during childhood. The phenotypic expression of narcolepsy in childhood is variable, and the onset of the disease is often monosymptomatic (4) . Narcolepsy should always be considered in cases where children display marked ES. Narcoleptic children can fall asleep as they talk, eat, or play, and the attacks of irresistible sleep might occur several times during the day. During the early stages of the disease, these children might have diffculty waking up in the morning at their usual times. They may also exhibit impair- ments in their performance at school. The differential diagnosis includes several sleep disorders that cause ES in children and adolescents. At the onset of narcolepsy, the patients may be mistakenly considered to be lazy or to have behavioral disorders. Delays in diagnosing this disease might result in severe issues during the literacy stage, psychosocial disorders, weight gain, and improper drug treatment (e.g., anticonvulsants, antipsychot- ics, antidepressants), among other adverse effects. A study of narcoleptic patients in the United Kingdom (5) demonstrated that the symptoms began during an age range of 1 to 68 years, with onset at an average age of 18 years. However,