Acute encephalitis induced Kleine-Levin syndrome with episodic vertical gaze dysfunction during hypersomnia episodes.

Kleine-Levin syndrome (KLS) is a rare, recurring sleep disorder that easily ignored. Episodic upward-gaze palsy is an uncommon manifestation observed in patients of KLS, which further complicates this disorder. Although peripheral microbial infection have been recognized as most common triggers for KLS, the underlying pathophysiology of this disorder remains unclear. We reported a unique case of KLS elicited by acute encephalitis, which was confirmed by pleocytosis of cerebrospinal fluid at the early stage. The cerebrospinal fluid returned to normal over time while the attacks continued to recur frequently. Episodic upward-gaze palsy was observed during attacks and clinical symptoms were exacerbated following a subsequent COVID-19 infection. This report presents a classic KLS case with distinctive characteristics, which should facilitate more accurate and earlier diagnosis for clinicians. Furthermore, it provides a new perspective for understanding the pathogenesis of this rare disease. CITATION: Lv H, Long X, Lv Y, Zhou J. Acute encephalitis induced Kleine-Levin syndrome with episodic vertical gaze dysfunction during hypersomnia episodes. J Clin Sleep Med. 2024;20(9):1555-1556.

Apparent resolution of hypersomnia episodes in two patients with Kleine-Levin syndrome following treatment with the melatonin receptor agonist ramelteon.

Kleine-Levin syndrome (KLS) is a rare disorder characterized by episodic bouts of severe hypersomnia associated with cognitive and behavioral abnormalities and normal alertness and functioning in between episodes. The pathophysiology is unclear but may involve neurotransmitter abnormalities, hypothalamic/thalamic dysfunction, viral/autoimmune etiology, or circadian abnormalities. No single treatment has been shown to be reliably efficacious; lithium has demonstrated the most consistent efficacy, although many do not respond and its use is limited by side effects. Due to the evidence of circadian involvement, we hypothesized that strengthening circadian signals may ameliorate symptoms. Ramelteon is a potent melatonin receptor agonist. In this report, two patients with KLS are described with apparent resolution of hypersomnia episodes following ramelteon initiation. CITATION: Dominguez D, Rudock R, Tomko S, Pathak S, Mignot E, Licis A. Apparent resolution of hypersomnia episodes in two patients with Kleine-Levin syndrome following treatment with the melatonin receptor agonist ramelteon. J Clin Sleep Med. 2024;20(4):657-662.

Idiopathic hypersomnia and Kleine-Levin syndrome.

Idiopathic hypersomnia (IH) and Kleine-Levin syndrome (KLS) are rare disorders of central hypersomnolence of unknown cause, affecting young people. However, increased sleep time and excessive daytime sleepiness (EDS) occur daily for years in IH, whereas they occur as relapsing/remitting episodes associated with cognitive and behavioural disturbances in KLS. Idiopathic hypersomnia is characterized by EDS, prolonged, unrefreshing sleep at night and during naps, and frequent morning sleep inertia, but rare sleep attacks, no cataplexy and sleep onset in REM periods as in narcolepsy. The diagnosis requires: (i) ruling out common causes of hypersomnolence, including mostly sleep apnea, insufficient sleep syndrome, psychiatric hypersomnia and narcolepsy; and (ii) obtaining objective EDS measures (mean latency at the multiple sleep latency test≤8min) or increased sleep time (sleep time>11h during a 18-24h bed rest). Treatment is similar to narcolepsy (except for preventive naps), including adapted work schedules, and off label use (after agreement from reference/competence centres) of modafinil, sodium oxybate, pitolisant, methylphenidate and solriamfetol. The diagnosis of KLS requires: (i) a reliable history of distinct episodes of one to several weeks; (ii) episodes contain severe hypersomnia (sleep>15h/d) associated with cognitive impairment (mental confusion and slowness, amnesia), derealisation, major apathy or disinhibited behaviour (hypersexuality, megaphagia, rudeness); and (iii) return to baseline sleep, cognition, behaviour and mood after episodes. EEG may contain slow rhythms during episodes, and rules out epilepsy. Functional brain imaging indicates hypoactivity of posterior associative cortex and hippocampus during symptomatic and asymptomatic periods. KLS attenuates with time when starting during teenage, including less frequent and less severe episodes. Adequate sleep habits, avoidance of alcohol and infections, as well as lithium and sometimes valproate (off label, after agreement from reference centres) help reducing the frequency and severity of episodes, and IV methylprednisolone helps reducing long (>30d) episode duration.

Sleep Disorder Kleine-Levin Syndrome (KLS) Joins the List of Polygenic Brain Disorders Associated with Obstetric Complications.

Kleine-Levin Syndrome is a rare neurological disorder with onset typically during adolescence that is characterized by recurrent episodes of hypersomnia, behavioral changes, and cognitive abnormalities, in the absence of structural changes in neuroimaging. As for many functional brain disorders, the exact disease mechanism in Kleine-Levin Syndrome is presently unknown, preventing the development of specific treatment approaches or protective measures. Here we review the pathophysiology and genetics of this functional brain disorder and then present a specific working hypothesis. A neurodevelopmental mechanism has been suspected based on associations with obstetric complications. Recent studies have focused on genetic factors whereby the first genome-wide association study (GWAS) in Kleine-Levin Syndrome has defined a linkage at the TRANK1 locus. A Gene x Environment interaction model involving obstetric complications was proposed based on concepts developed for other functional brain disorders. To stimulate future research, we here performed annotations of the genes under consideration for Kleine-Levin Syndrome in relation to factors expected to be associated with obstetric complications. Annotations used data-mining of gene/protein lists related to for hypoxia, ischemia, and vascular factors and targeted literature searches. Tentative links for TRANK1, four additional genes in the TRANK1 locus, and LMOD3-LMO2 are described. Protein interaction data for TRANK1 indicate links to CBX2, CBX4, and KDM3A, that in turn can be tied to hypoxia. Taken together, the neurological sleep disorder, Kleine-Levin Syndrome, shows genetic and mechanistic overlap with well analyzed brain disorders such as schizophrenia, autism spectrum disorder and ADHD in which polygenic predisposition interacts with external events during brain development, including obstetric complications.

Kleine-Levin syndrome: report of a case with marked dysautonomic features.

Kleine-Levin syndrome is a rare neurologic disorder of unknown etiopathogenesis, characterized by abrupt onset and remission of attacks of hypersomnia and cognitive dysfunctions. Psychiatric symptoms are frequently present, ranging from disinhibited sexual behavior and eating disorders to hallucinations, anxiety, mood alterations, and derealization. A vast range of attack-related dysautonomic signs and symptoms are reported but remain poorly described. We describe a patient with Kleine-Levin syndrome with sleep attacks dominated by marked dysautonomic features. We briefly review similar clinical cases and suggest that the hypothalamus may play a central role in the genesis of autonomic dysfunction in Kleine-Levin syndrome. CITATION: Fiamingo G, Esposto R, Dal Fabbro B, Terzaghi M. Kleine-Levin syndrome: report of a case with marked dysautonomic features. J Clin Sleep Med. 2022;18(9):2313-2316.

Kleine-Levin syndrome is associated with birth difficulties and genetic variants in the TRANK1 gene loci.

Kleine-Levin syndrome (KLS) is a rare disorder characterized by severe episodic hypersomnia, with cognitive impairment accompanied by apathy or disinhibition. Pathophysiology is unknown, although imaging studies indicate decreased activity in hypothalamic/thalamic areas during episodes. Familial occurrence is increased, and risk is associated with reports of a difficult birth. We conducted a worldwide case-control genome-wide association study in 673 KLS cases collected over 14 y, and ethnically matched 15,341 control individuals. We found a strong genome-wide significant association (rs71947865, Odds Ratio [OR] = 1.48, P = 8.6 × 10-9) within the 3'region of TRANK1 gene locus, previously associated with bipolar disorder and schizophrenia. Strikingly, KLS cases with rs71947865 variant had significantly increased reports of a difficult birth. As perinatal outcomes have dramatically improved over the last 40 y, we further stratified our sample by birth years and found that recent cases had a significantly reduced rs71947865 association. While the rs71947865 association did not replicate in the entire follow-up sample of 171 KLS cases, rs71947865 was significantly associated with KLS in the subset follow-up sample of 59 KLS cases who reported birth difficulties (OR = 1.54, P = 0.01). Genetic liability of KLS as explained by polygenic risk scores was increased (pseudo R2 = 0.15; P < 2.0 × 10-22 at P = 0.5 threshold) in the follow-up sample. Pathway analysis of genetic associations identified enrichment of circadian regulation pathway genes in KLS cases. Our results suggest links between KLS, circadian regulation, and bipolar disorder, and indicate that the TRANK1 polymorphisms in conjunction with reported birth difficulties may predispose to KLS.

Obstructive sleep apnoea with co existent Kleine-Levine syndrome in a middle-aged man.

Hypersomnia is a symptom which is pathognomonic of patients with Kleine-Levin syndrome (KLS), but the cause of this finding remains undefined. Given the pervasive association between obstructive sleep apnoea (OSA) and excessive daytime sleepiness, there exists the possibility that OSA might contribute to the sleepiness exhibited by these patients. Here we report a middle age man who had excessive daytime sleepiness and diagnosed as OSA after polysomnography. Prescribing of continuous positive airway pressure (CPAP) lead to unmasking of episodes of increased sleepiness and other behavioural features of KLS.

[Sleep disorders in neurological department and Kleine-Levin syndrome]. / Rasstroistva sna v nevrologicheskom statsionare i sindrom Kliaine-Levina.

The authors present a case-report of a 22-year-old man with Kleine-Levin syndrome (KLS) and consider the historical description of the syndrome, its symptoms, diagnostic criteria, its place in modern classifications of sleep disorders and KLS pathogenesis. Own data on the frequency of different sleep disorders in inpatients of a neurological unit are presented.

Sleeping beauty syndrome presenting with insomnia.

A young man previously diagnosed with Kleine-Levin syndrome (KLS) presented with abnormal behaviour over the last 8 days. This included decreased sleeping hours and appetite, hypersexuality, aggressiveness and visual hallucinations. All blood tests and investigations in the emergency department yielded normal results. A preliminary diagnosis of a KLS episode with psychosis was made and the patient was started on a regimen of aripiprazole 10 mg once daily along with lorazepam 2 mg intravenously in two divided doses in the event of agitation or insomnia. On discharge 5 days later, the patient had returned to his premorbid level of functioning and was willing to follow up in the neurology clinic. He was discharged on aripiprazole 10 mg once daily and lorazepam 2 mg two times daily as needed for 2 weeks to help with his agitation and insomnia, as well as lithium carbonate 400 mg at night.

Breathing abnormalities during sleep in Kleine-Levin Syndrome: fact or coincidence?

PURPOSE OF REVIEW: To highlight and critically discuss the possibility that breathing abnormalities during hypersomnolent episodes are an additional clinical feature of Kleine-Levin Syndrome (KLS). RECENT FINDINGS: A computerized literature search of breathing abnormalities in patients with KLS disclosed two old and a single recent publication describing a total of six patients with sleep apnea during hypersomnolent episodes. SUMMARY: Owing to scarce reports on complete polysomnography during and in-between hypersomnic episodes of KLS, the possibility that breathing abnormalities are an additional clinical feature of this unique episodic sleep syndrome should be further studied.

The clinical characteristics of Kleine-Levin syndrome according to ethnicity and geographic location.

PURPOSE: Kleine-Levin syndrome (KLS) is a rare, relapsing-remitting, debilitating sleep disorder. Examining KLS characteristics in different ethnic populations may help elucidate the genetic basis of the disorder. No studies have examined KLS in Arabs. Therefore, we compared the clinical characteristics of Saudi Arabian KLS patients to those in other published cohorts to determine whether Arab patients have a distinct phenotype. METHODS: This study included all patients who were diagnosed with KLS at our center between June 2003 and July 2016 (P = 12; Six familial cases). All participants completed the Stanford KLS questionnaire. Anxiety and depression were assessed using the Hospital Anxiety and Depression Scale; eating attitudes were assessed with the Eating Attitudes Test-26. We compared the clinical characteristics of our patients to those in other published cohorts. RESULTS: Saudi Arabian patients with KLS had similar features to those in patients from different countries and ethnic backgrounds, with only minor differences in sleep duration during disease episodes (2-3 h shorter). However, between episodes, Saudi Arabian KLS patients reported worse sleep, greater daytime sleepiness and higher levels of baseline depression, which may be related to KLS or to local cultural practices. Ankylosing spondylitis was present in five of the six familial patients. CONCLUSION: Saudi Arabian patients with KLS exhibited similar clinical characteristics during episodes compared to patients with KLS of different ethnicities. However, a new and interesting finding is that KLS patients may have inter-episode behavioral and pathophysiological changes, which may suggest that KLS is not necessarily a static disorder.

[A young boy with periodic strange behavior and hypersomnia: Kleine-Levin syndrome]. / Een puber met periodiek vreemd gedrag en slaperigheid: syndroom van Kleine-Levin.

Kleine-Levin syndrome is a rare neuro-psychiatric disease. Most of the young patients are males who present with hypersomnia, cognitive dysfunction, altered perception, eating disorder (e.g. hyperphagia) or disinhibited behaviour (e.g. hypersexuality). Psychiatric symptoms such as apathy, delusions and hallucinations, depressed mood and compulsive behaviours also appear often and result frequently in a psychiatric referral. These symptoms, however, should be distinguished from those of psychiatric diseases as early as possible in order to ensure that patients do not receive the wrong treatment. We present the case of an 11-year-old boy in whom the psychiatric symptoms were initially the most prominent ones.

[Clinical presentation of Kleine-Levin syndrome].

Objective: To analyze the clinical features of Kleine-Levin syndrome (KLS) patients. Methods: Clinical data of 44 patients with KLS of the Sleep Center of Peking University People's Hospital from January 2002 to July 2013 were systematically reviewed. The predisposing factors and clinical presentations were summarized, and compared with the data from a Western KLS study with a large subjects number. Nocturnal polysomnography (PSG) and multiple sleep latency test (MSLT) were conducted during relapse and remission period, respectively. HLA-DQB1*0602 gene were screened and analyzed. Results: Among the 44 patients, 28(63.6%) were men and 16(36.4%) were women, with a mean age of (18.3±8.9) years old. Most patients developed the symptoms during adolescence. Infection or fever was the most common trigger for episode. The main clinical presentations were 44(100.0%) hypersomnia, 31(70.5%) forgetfulness, 26(59.1%) decreased appetites, 24(54.5%) juvenile behavior, 18(40.9%) depression, etc. Compared with the Western study, it showed that our patients had decreased instead of increased appetite. The PSG testing did not have remarkable findings. MSLT showed mean sleep latency was significantly shorter during relapse than during remission [(10.4±5.4) vs (15.3±3.4) min, P=0.009]. HLA-DQB1*0602 was positive in 12 of 40(30.0%) patients, which was similar to the data in the Chinese population. Conclusions: KLS has various clinical characteristics. The presentation of appetite may be different between Chinese and western KLS patients.

[Kleine Levin Syndrome: more than just periodic hypersomnia]. / Kleine-Levin-syndroom: meer dan periodieke hypersomnie.

BACKGROUND: Kleine Levin Syndrome (KLS) is a rare disease with periodic hypersomnia as its main feature. Hyperphagia and hypersexuality are also described as classical symptoms, although quite recently it has become clear that the full triad is absent in the majority of patients. CASE DESCRIPTION: A 14-year-old boy developed KLS after a period of flu-like symptoms. Over the course of three years he suffered from seven one-week episodes of extreme hypersomnia (sleeping 18 hours a day), depersonalisation, apathy, anxiety, paranoia, confusion, hallucinations and uninhibited sexual behaviour. He ate little. Ancillary investigations did not reveal any abnormalities. In between these episodes he had no symptoms. CONCLUSION: From this case description and a summary of the symptoms of twelve other patients with KLS, it appears that neuropsychiatric symptoms are much more prominent than hyperphagia and hypersexuality. It is important that the typical KLS phenotype be reappraised, so that the condition can be recognised early and patients managed appropriately.

Familial Kleine-Levin Syndrome: A Specific Entity?

STUDY OBJECTIVES: Kleine-Levin syndrome (KLS) is a rare, mostly sporadic disorder, characterized by intermittent episodes of hypersomnia plus cognitive and behavior disorders. Although its cause is unknown, multiplex families have been described. We contrasted the clinical and biological features of familial versus sporadic KLS. METHODS: Two samples of patients with KLS from the United States and France (n = 260) were studied using clinical interviews and human leukocyte antigen (HLA) genotyping. A multiplex family contained two or more first- or second-degree affected relatives (familial cases). RESULTS: Twenty-one patients from 10 multiplex families (siblings: n = 12, including two pairs of monozygotic twins; parent-child: n = 4; cousins: n = 2; uncle-nephews: n = 3) and 239 patients with sporadic KLS were identified, yielding to 4% multiplex families and 8% familial cases. The simplex and multiplex families did not differ for autoimmune, neurological, and psychiatric disorders. Age, sex ratio, ethnicity, HLA typing, karyotyping, disease course, frequency, and duration of KLS episodes did not differ between groups. Episodes were less frequent in familial versus sporadic KLS (2.3 ± 1.8/y versus 3.8 ± 3.7/y, P = 0.004). Menses triggered more frequently KLS onset in the nine girls with familial KLS (relative risk, RR = 4.12, P = 0.03), but not subsequent episodes. Familial cases had less disinhibited speech (RR = 3.44, P = 0.049), less combined hypophagia/hyperphagia (RR = 4.38, P = 0.006), more abrupt termination of episodes (RR = 1.45, P = 0.04) and less postepisode insomnia (RR = 2.16, P = 0.008). There was similar HLA DQB1 distribution in familial versus sporadic cases and no abnormal karyotypes. CONCLUSION: Familial KLS is mostly present in the same generation, and is clinically similar to but slightly less severe than sporadic KLS.

Kleine-Levin Syndrome: An Overview and Relevance to Nursing Practice.

Kleine-Levin syndrome (KLS) is a neuropsychiatric sleep disorder primarily affecting adolescent males. Onset is insidious, idiopathic, and hastened by neurological incident or infection. Typically, the initial onset occurs during the teen years or after the second decade, although cases have been documented in early childhood, adulthood, and senescence. KLS is marked by unexpected debilitating, yet reversible, episodic hypersomnia, with varying recurrence rates; cognitive and behavioral impairment; compulsive eating; and feelings of derealization, hypersexuality, apathy, and depressed mood. Diagnosis is problematic due to the syndrome's rarity, disparity of presenting clinical symptoms, and misdiagnosis. Correct diagnosis can take up to 4 years. The clinical course is approximately 8 to 14 years from initial onset, yet may be longer in the adult form of the disorder. KLS has been shown to impact activities of daily living, usurping an adolescent of his/her social relations with peers, experiences, and time.

Long-Term Cognitive Impairment in Kleine-Levin Syndrome.

STUDY OBJECTIVES: In Kleine-Levin syndrome (KLS), episodes of hypersomnia, cognitive, and behavioral disturbances alternate with asymptomatic periods. Because 50% of patients report decreased academic performances, we evaluated their cognitive status during asymptomatic periods, determinants of deficits, and changes during follow-up. METHODS: The cognitive assessment during asymptomatic periods in all consecutive patients with typical KLS and healthy controls included the non-verbal intelligence quotient (Raven Progressive Matrices), the Trail Making Test, the Stroop Color-Word Test, the Wechsler Memory Test, verbal fluencies, the Free and Cued Learning Memory Test, and the Rey-Osterreith Complex Figure. Cognitive status was reevaluated after 0.5 to 2 y in 44 patients. RESULTS: At baseline, compared with the 42 controls, the 122 patients with KLS exhibited lower non-verbal intelligence quotient, speed of processing, attention, and reduced retrieval strategies in episodic memory. Higher episode frequency, shorter episode duration, shorter time since last episode, deeper sleep, and megaphagia during episodes predicted impaired memory. The visuoconstructional abilities and non-verbal memory were intact. After a mean follow-up of 1.7 ± 1.0 y, the episode frequency decreased from 4.6 ± 4.8 to 1.7 ± 1.9/y. The logical reasoning and attention improved, the processing speed remained low, and the retrieval strategies in verbal memory further worsened. CONCLUSIONS: In this field study, one-third of patients with KLS have long-term cognitive deficits affecting retrieval and processing speed. Cognitive function should be systematically tested in patients with KLS, which appears important to help patients in their academic studies.

Preliminary results on CSF biomarkers for hypothalamic dysfunction in Kleine-Levin syndrome.

OBJECTIVE: To measure CSF biomarkers of hypothalamic dysfunction in patients with typical Kleine-Levin syndrome (KLS) during symptomatic and asymptomatic periods. PATIENTS/METHODS: Two patients with typical KLS were admitted during symptomatic and asymptomatic periods to a research Sleep Disorders Center. Cerebrospinalfluid (CSF) hypocretin-1, histamine (HA), and its major metabolite tele-methylhistamine (t-MHA) levels were measured in two KLS patients in and out of episode. RESULTS: CSF biomarkers of hypothalamic dysfunction measured in two KLS patients in and out of episode revealed low hypocretin levels (within the narcolepsy-cataplexy range) during a hypersomnia episode in the more severe patient, and a 42% decrease (although within normal range) in the second patient. CSF HA and t-MHA measurements in and out of episode revealed a two-fold in-episode decrease in HA in the more severe patient, with no significant change for the second patient, nor for t-MHA levels. CONCLUSION: We reported reversible changes in CSF hypothalamic biomarkers in a typical patient with KLS that reinforces the hypothesis that in some patients KLS episodes may be caused by recurrent functional alterations of the hypothalamus.