title: Kleine-Levin syndrome in 120 patients: differential diagnosis and long episodes.
abstract: OBJECTIVE
  Kleine-Levin syndrome is a rare disease characterized by recurrent episodes of hypersomnia with behavioral and cognitive disturbances. We aimed at describing the diagnosis procedure, risk factors, and severe forms.
  
  
  METHODS
  In consecutive patients referred for suspected Kleine-Levin syndrome, we detailed differential diagnoses, and atypical and secondary cases, compared typical patients with healthy subjects, and examined the characteristics of patients with prolonged (>30 days) episodes.
  
  
  RESULTS
  Among 166 referred patients, 120 had typical primary Kleine-Levin syndrome (syndrome secondary to brain diseases; n = 4, atypical syndrome, n = 7; differential diagnoses that were mostly psychiatric, n = 29; incomplete information, n = 6). The prevalence in France was 1.8 per million. The patients were often male (64%) and had more frequent birth and developmental abnormalities (45%) than controls (despite normal karyotypes), and most (80%) had teenage onset, with no difference between patients with prolonged (n = 34) and short (n = 85) episodes. In patients with prolonged episodes, the durations of the first episode (32 ± 33 vs 11 ± 6 days) and subsequent episodes were longer (mean episode duration = 23 ± 19 vs 10 ± 3 days) and the disease course tended to be longer (9 ± 6 vs 6 ± 4 years). During episodes, patients with prolonged episodes had shorter sleep time, higher levels of anxiety, increased agitation, and more feelings of disembodiment and amnesia. Between episodes, they were more tired, needed more naps, fell asleep more rapidly, and had higher anxiety/depression scores.
  
  
  CONCLUSIONS
  Mental disorders are frequent differential diagnoses of Kleine-Levin syndrome. One-third of patients have prolonged (>1 month) episodes with more frequent immediate and long-term consequences of the disease, prompting therapeutic trials.
authors.affiliation: Sleep Disorders Unit, Pitié-Salpêtrière University Hospital, Public Hospital Network of Paris, Paris; Brain Research Institute, Sorbonne Universities, Pierre and Marie Curie University, Paris; National Reference Center: Narcolepsy, Hypersomnia, and Kleine-Levin Syndrome, Paris.
authors.forename: Sophie
authors.initials: S
authors.lastname: Lavault
authors.forename: Jean-Louis
authors.initials: JL
authors.lastname: Golmard
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Groos
authors.forename: Agnès
authors.initials: A
authors.lastname: Brion
authors.forename: Yves
authors.initials: Y
authors.lastname: Dauvilliers
authors.forename: Michel
authors.initials: M
authors.lastname: Lecendreux
authors.forename: Patricia
authors.initials: P
authors.lastname: Franco
authors.forename: Isabelle
authors.initials: I
authors.lastname: Arnulf
mesh_terms: D000328:Adult; D017668:Age of Onset; D003937:Diagnosis, Differential; D018450:Disease Progression; D005260:Female; D005602:France / Q000453:epidemiology; D006801:Humans; D017593:Kleine-Levin Syndrome / Q000175:diagnosis* / Q000453:epidemiology / Q000503:physiopathology; D008297:Male; D001523:Mental Disorders / Q000175:diagnosis; D012307:Risk Factors; D012737:Sex Factors; D013997:Time Factors; D055815:Young Adult