Kleine-Levin syndrome (KLS) is a rare disorder that causes recurring periods of excessive sleepiness. In some cases, this means up to 20 hours a day are spent ...WhatIsKleine-LevinSyndrome(KLS)?MedicallyreviewedbyRickyChen,M.D.—WrittenbyValenciaHiguera—UpdatedonNovember14,2018SymptomsCausesandriskfactorsDiagnosisManagementCopingOutlookKLSisalsoknownas“sleepingbeautysyndrome”Kleine-Levinsyndrome(KLS)isararedisorderthatcausesrecurringperiodsofexcessivesleepiness.Insomecases,thismeansupto20hoursadayarespentsleeping.Forthisreason,theconditioniscommonlyreferredtoas“sleepingbeautysyndrome.”KLScanalsoproducechangesinbehaviorandconfusion.Thisdisordercanaffectanyone,butteenageboysdeveloptheconditionmorethananyothergroup.About70percentofpeoplewiththisdisorderaremale.Episodescancomeandgooveranextendedperiodoftime.Sometimesthey’reonandoffforaslongas10years.Duringeachepisode,itcanbedifficulttoattendschool,work,orparticipateinotheractivities.Whatarethesymptoms?PeoplelivingwithKLSmaynotexperiencesymptomseveryday.Infact,affectedindividualstypicallydon’thaveanysymptomsbetweenepisodes.Whensymptomsdoappear,theycanlastafewdays,weeks,orevenmonths.Commonsymptomsincludeextremesleepiness.Theremaybeastrongdesiretogotobedandtroublegettingupinthemorning.Duringanepisode,it’snotuncommontosleepupto20hoursaday.PeoplelivingwithKLSmaygetuptousethebathroomandeat,thengobacktosleep.FatiguecanbesoseverethatpeoplewithKLSarebedriddenuntilanepisodepasses.Thistakestimeandenergyawayfromfamily,friends,andpersonalobligations.Episodescanalsotriggerothersymptoms,suchas:hallucinationsdisorientationirritabilitychildishbehaviorincreasedappetiteexcessivesexdriveThismayresultfromreducedbloodflowtopartsofthebrainduringanepisode.KLSisanunpredictablecondition.Episodescanrecursuddenlyandwithoutwarningweeks,months,oryearslater.Mostpeopleresumenormalactivityafteranepisodewithoutanybehavioralorphysicaldysfunction.However,theymayhavelittlememoryofwhathappenedduringtheirepisode.WhatcausesKLSandwho’satrisk?TheexactcauseofKLSi