Clinical and polysomnographic characteristics of 34 patients with Kleine–Levin syndrome

Abstract

There is only scant information on sleep characteristics and long-term follow-up in patients with Kleine-Levin syndrome (KLS). This study describes the clinical course, results of polysomnography and long-term follow-up in a relatively large group of patients with KLS. During the years 1982-97, we encountered 34 patients (26 males and eight females) with KLS. We were able to obtain the original polysomnographs from 28 males and four females. In 25 patients, data regarding their present state of health were obtained. Fourteen agreed to be present at a detailed interview and examination while 11 gave the information by phone. The mean age at onset was 15.8 +/- 2.8 years and the mean diagnostic delay, 3.8 +/- 4.2 years. The mean duration of a single hypersomnolent attack was 11.5 +/- 6.6 days. The main abnormal findings extracted out of 35 polysomnographs obtained from 32 patients during and/or in-between attacks included: decreased sleep efficiency, and frequent awakenings from sleep stage 2. All 25 patients reported present perfect health, with no evidence of behavioral or endocrine dysfunction. In adolescents with periodic hypersomnia, the diagnosis of KLS should be explored. Sleep recordings during a hypersomnolent period will often show frequent awakenings from sleep stage 2. The long-term prognosis is excellent.

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

“…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.…”

The protean manifestations of childhood narcolepsy and their misinterpretation

“…In the admittedly rare Kleine-Levin syndrome, 4 the onset of which is usually in adolescence, often out of character and bizarre behaviours occur in the short period when the patient is awake each 24 hours. These, and the return to normality between each episode of hypersomnolence, are likely to lead to various misdiagnoses of a physical or psychiatric type.…”

PANDAS and Comorbid Kleine–Levin Syndrome

“…However, this association is of unknown relevance to our patient's clinical presentation. Viral infections, including various febrile illnesses (Gillberg 1987;Gadoth et al 2001), URIs (Arnulf et al 2005;Huang et al 2012b), encephalitis (Merriam 1986;Fenzi et al 1993;Huang et al 2012b), and Epstein-Barr and varicella-zoster (Salter and White 1993) have been reported as precipitating factors in KLS. PANDAS exacerbations have been correlated with GAS infections (Swedo et al 1998;Mell et al 2005;Murphy et al 2012).…”

“…The average age of onset is 15 years, and males are more frequently affected than females (Gadoth et al 2001;Arnulf et al 2005Arnulf et al , 2008. Active episodes have an average duration of 10-13 days with reoccurrences averaging every 3.5 months, with patients typically asymptomatic between episodes (Arnulf et al 2005(Arnulf et al , 2008.…”