Kleine–Levin syndrome in 120 patients: Differential diagnosis and long episodes

Abstract

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.

Prevalence and Mimics of Kleine-Levin Syndrome: A Survey in French-Speaking Switzerland

“…Our estimated KLS prevalence seems somewhat higher than previously published data: 1.5 per million worldwide, 13 and 1.8 per million in France, 8 but the difference is not statistically significant compared to France. The geographical distribution of KLS patients and the marked overrepresentation of subjects from the canton of Vaud may suggest that this entity could remain underdiagnosed in some areas with limited access to specialized centers.…”

“…We might still have missed some KLS patients, despite contacting all certified sleep centers and neurologist in the study region; alternatively, a yet unidentified factor related to genetics or exposure could be at play-indeed, KLS prevalence also strongly varies across French regions. 8 The mean latency of diagnosis of KLS patients in our study (20 months) appears shorter than previously described: about 4 years in 2001 (in Israel), 15 and 2 years in 2011 (in France), 10 and may suggest a natural fluctuation, or that increasing KLS awareness may influence diagnosis. However, the fact that in our study 6 of 7 patients have been diagnosed after 2009 favors the second hypothesis.…”

“…8 Five subjects were living in the canton of Vaud, and the remaining two in Fribourg and Valais (see Figure S1 in the supplemental material).…”

“…[3][4][5][6][7] Several precipitating factors have been described before the occurrence of an episode, among which are infections, alcohol consumption, sleep deprivation, unusual stress, and head trauma. 2,[8][9][10][11] A study pointed to a significantly increased HLA-DQB1*0201 allele frequency in KLS patients, reinforcing the hypothesis of a possible autoimmune origin, but this has not been confirmed in a larger cohort. 2,12 To date, no placebo-controlled trials concerning treatment management are available, although lithium seems to be the most efficacious prophylactic drug for patients with frequent and disabling episodes.…”

“…2,11,13,14 The prevalence of KLS, classically estimated at 1 per million, has been recently evaluated at 1.8 cases per million in France. 8 At our center, we currently follow several KLS patients, which led us to suspect a higher prevalence than described in the literature. Moreover, in recent years we also ruled out KLS diagnosis in a consistent number of patients referred for this suspicion.…”