Kleine-Levin syndrome. Clinical boarderlands based on a thorough analysis of 475 case reports.

OBJECTIVE/BACKGROUND: Kleine-Levin syndrome (KLS) is a rare sleep disorder characterized by recurrent episodes of severe hypersomnolence in association with various degrees of cognitive impairment, perceptive abnormalities, apathy, behavioral disturbances. Some of these symptoms, hypersomnolence, compulsive eating and increased sexual drive may be replaced by their opposites or alternate with them. Remarkably enough, these « atypical symptoms ¼ have never been enlighted nor compared in frequency with corresponding typical symptoms. Besides, KLS is more frequent in males than in females but no review has ever compared the frequency of precipitating factors and symptoms in males and females. PATIENTS/METHODS: To uncover these as yet uninvestigated aspects of KLS, a predesigned template was used to extract precipitating factors and symptoms, in 475 case reports of KLS, comprising 364 males and 111 females. RESULTS: Precipitating factors were more frequently recorded in males (67.31 %) than in females (49.55 %). Recurrent episodes of hypersomnolencee were present in 94.32 % of cases, recurrent insomnia in 1.05 % and alternation of hypersomnolence and insomnia in 4.63 %. Cognitive impairment was present in 67.37 % of cases and absent in 6.95 %. Derealization/altered perception was present in 38.32 % of cases and absent in 1.68 %. Severe apathy was present in 44.63 % of cases. Compulsive eating was present in 59.58 % of cases, absent in 13.26 %, replaced by anorexia in 9.05 %, alternation of compulsive eating and anorexia in 5.68 % and alternation of compulsive eating and no compulsive eating in 8.42 %. Increased sexual drive was present in 33.68 % of cases, absent in 22.74 %, replaced by decreased sexual drive in 1.47 %, alternation of increased sexual drive and no increased sexual drive in 2.95 %. Odd behaviors were present in 45.05 % of cases. Psychiatric features were present in 71.58 % of cases, absent in 2.95 %. Finally, the percentages of precipitating factors and of sleep disorder, apathy, sexual disorder, irritability/agressivity, were higher in males than in females. CONCLUSIONS: The frequency of the opposites of hypersomnolence, compulsive eating and increased sexual drive appears to be quite significant. In addition, a systematic comparison of precipitating factors and symptoms in males and females has shown limited differences between sexes.

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 an unique case of KLS elicited by acute encephalitis, which was confirmed by pleocytosis of cerebrospinal fluid (CSF) at the early stage. The CSF 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.

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.

Genetics and epigenetics of rare hypersomnia.

Herein we focus on connections between genetics and some central disorders of hypersomnolence - narcolepsy types 1 and 2 (NT1, NT2), idiopathic hypersomnia (IH), and Kleine-Levin syndrome (KLS) - for a better understanding of their etiopathogenetic mechanisms and a better diagnostic and therapeutic definition. Gene pleiotropism influences neurological and sleep disorders such as hypersomnia; therefore, genetics allows us to uncover common pathways to different pathologies, with potential new therapeutic perspectives. An important body of evidence has accumulated on NT1 and IH, allowing a better understanding of etiopathogenesis, disease biomarkers, and possible new therapeutic approaches. Further studies are needed in the field of epigenetics, which has a potential role in the modulation of biological specific hypersomnia pathways.

Kleine-levin syndrome comorbid with obsessive compulsive disorder and personality disorder: A case report.

Background: Kleine-Levin syndrome (KLS) is a rare sleep disorder with at least two episodes of hypersomnia coincidence with at least one cognitive, eating, perceptive and disinhibited symptoms and normal inter-episodes. These symptoms are not explained by another sleep, medical, neurological, psychiatric disorders and substance or drug use. Case Presentation: Here we report a young female with personality disorder and obsessive-compulsive disorder who had KLS. Her symptoms appeared in the past 1.5 years ago, while she had an episode of hypersomnia lasting for 5 days. She had 4 attacks; each one lasted up to 2-7 days. We found that overriding KLS symptoms on underlying main psychiatric or personality disorders complicates diagnosis. All neurological examinations during episode and further investigation were in normal range. Conclusion: We suggest that taking a complete history and mental state examination in the episode and inter episode phase helps to diagnosis both KLS and comorbid psychiatric disorders.

Approach to a sleepy child: Diagnosis and treatment of excessive daytime sleepiness in children and adolescents.

PURPOSE: The aim of this review is to give updated information to pediatric neurologists on the correct diagnostic approach and treatment of excessive daytime sleepiness (EDS) in children and adolescents. Due to the change in the society habits, EDS is becoming an emerging problem for the health system. At the present there are few articles specifically devoted to the evaluation of EDS. EDS is often reported in several manuscripts as a side effect of other sleep disorders (obstructive sleep apnea, circadian disorders, etc.) or of the use of drugs or of the substance abuse or as a consequence of bad sleep habits and poor sleep hygiene. EDS, especially in children, may manifest with paradoxical symptoms like hyperactivity, inattention, and impulsiveness. However, common sign of EDS in children are the propensity to sleep longer than usual, the difficulty waking up in the morning, and falling asleep frequently during the day in monotonous situation. The diagnosis should include subjective (sleep diaries, questionnaires) and objective (polysomnography, multiple sleep latency test, etc.) instruments to avoid misdiagnosis. Narcolepsy is the most studied central disorder of hypersomnolence, and it is a predominantly pediatric disease with a peak age of onset in prepuberty but the diagnosis is often delayed especially in mild forms. The early and correct treatment of narcolepsy and of other form of EDS is extremely important since late and inappropriate treatments can affect the psychosocial development of the children and adolescents.

A case of Kleine-Levin syndrome arising during chemotherapy: efficacy of oral L-carnitine.

A woman in her 50 s with Kleine-Levin syndrome (KLS) was referred to our sleep clinic for recurrent episodes of sleep hypersomnia lasting for two to 3 days, despite attempts to remain awake. These episodes were unaccompanied by anxiety or depression, increased appetite, increased sex drive, irritability, or hallucinations, and had first appeared during chemotherapy for malignant lymphoma. Video polysomnography revealed mild obstructive sleep apnea syndrome (apnea-hypopnea index 7.9/h), but no other abnormalities. All blood tests and brain imaging investigations, including brain MRI and A 123I-ioflupane SPECT, yielded normal results. Oral L-carnitine was found to be effective for shortening the period of hypersomnolence, reducing the degree of hypersomnolence, and prolonging the inter-episode period. Since it has been reported that alkylating agents may induce carnitine deficiency, the present observations appear to support the involvement of carnitine in the onset of KLS.

Perioperative Considerations in a Patient with Kleine-Levin Syndrome Undergoing a Neurosurgical Procedure under General Anesthesia.

Kleine-Levin syndrome (KLS) is a rare central disorder of daytime hypersomnolence and is often characterized by a relapsing and remitting course, recurrent episodes of excessive sleep lasting from 12 to 20 hours a day, and symptoms including hyperphagia, hallucinations, derealization, disorientation, and hypersexuality. There are numerous perioperative considerations in dealing with KLS that include challenges during induction of anesthesia, delayed emergence, postoperative sleep disorders, and delirium. However, due to its rare occurrence, the anesthetic considerations of KLS remain poorly described. This case report outlines the anesthetic considerations and management of a young female patient with KLS who underwent transnasal excision of a trigeminal schwannoma under general anesthesia.

COVID-19 and Central Nervous System Hypersomnias.

Purpose of review: Central nervous system (CNS) hypersomnias can be triggered by external factors, such as infection or as a response to vaccination. The 2019 coronavirus disease (COVID-19) pandemic, which was caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), led to a worldwide effort to quickly develop a vaccine to contain the pandemic and reduce morbidity and mortality. This narrative review is focused on the literature published in the past 2 years and provides an update on current knowledge in respect of the triggering of CNS hypersomnias by infection per se, vaccination, and circadian rhythm alterations caused by social isolation, lockdown, and quarantine. Recent findings: At present, there is no consensus on the association between hypersomnias and COVID-19 vaccination or infection per se; however, the data suggest that there has been an increase in excessive daytime sleepiness due to vaccination, but only for a short duration. Kleine Levin syndrome, hypersomnia, excessive daytime sleepiness, and narcolepsy were aggravated and exacerbated in some case reports in the literature. Both increased and decreased sleep duration and improved and worsened sleep quality were described. In all age groups, delayed sleep time was frequent in studies of patients with hypersomnolence. Summary: The hypothesis that there is a pathophysiological mechanism by which the virus, vaccination, and the effects of quarantine aggravate hypersomnias is discussed in this review.

A case of Kleine-Levin syndrome successfully treated with Escitalopram.

Kleine-Levin syndrome (KLS) is an extremely rare relapsing-remitting neuropsychiatric condition characterized by recurrent incidents of major hypersomnolence along with hyperphagia, hypersexual behavior, and mood or cognitive disturbances alternating with asymptomatic periods. Here, we present a case of a young male chiefly presenting with recurring episodes of acute onset behavioral changes. The patient's episodes were characterized by repetitive incidents of prolonged sleep for more than 20 h, followed by social withdrawal and apathy. He was diagnosed with KLS because of the periodic patterns of hypersomnolence accompanied by other cognitive and mood disturbances and lacked characteristics of central hypersomnolence disorders or atypical depression. There are varying success rates among medications such as lithium, stimulants such as modafinil, antiepileptics such as carbamazepine and valproate. Similarly, the use of antidepressants such as tricyclic agents and selective serotonin reuptake inhibitors has largely been negative. Our case report addresses a patient with KLS who was successfully treated with 20 mg of Escitalopram.

Neuroimaging in the Rare Sleep Disorder of Kleine-Levin Syndrome: A Systematic Review.

Kleine-Levin syndrome (KLS) is characterized by episodes of hypersomnia. Additionally, these patients can present with hyperphagia, hypersexuality, abnormal behavior, and cognitive dysfunction. Functional neuroimaging studies such as fMRI-BOLD, Positron Emission Tomography (PET) or SPECT help us understand the neuropathological bases of different disorders. We conducted a systematic review to investigate the neuroimaging features of KLS patients and their clinical correlations. This systematic review was conducted by following the Meta-Analysis of Observational Studies in Epidemiology (MOOSE) and PRISMA protocol reporting guidelines. We aim to investigate the clinical correlation with neuroimaging among patients with KLS. We included only studies written in the English language in the last 20 years, conducted on humans; 10 studies were included. We excluded systematic reviews, metanalysis, and case reports. We found that there are changes in functional imaging studies during the symptomatic and asymptomatic periods as well as in between episodes in patients with K.L.S. The areas most reported as affected were the hypothalamic and thalamic regions, which showed hypoperfusion and, in a few cases, hyperperfusion; areas such as the frontal, parietal, occipital and the prefrontal cortex all showed alterations in cerebral perfusion. These changes in cerebral blood flow and regions vary according to the imaging (SPECT, PET SCAN, or fMRI) and the task performed while imaging was performed. We encountered conflicting data between studies. Hyper insomnia, the main feature of this disease during the symptomatic periods, was associated with decreased thalamic activity. Other features of K.L.S., such as apathy, hypersexuality, and depersonalization, were also correlated with functional imaging changes. There were also findings that correlated with working memory deficits seen in this stage during the asymptomatic periods. Hyperactivity of the thalamus and hypothalamus were the main features shown during the asymptomatic period. Additionally, functional imaging tends to improve with a longer course of the disease, which suggests that K.L.S. patients outgrow the disease. These findings should caution physicians when analyzing and correlating neuroimaging findings with the disease.

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.

General Anesthetic Management of a Patient With Kleine-Levin Syndrome.

Kleine-Levin syndrome (KLS) is a rare sleep disorder characterized by periodic hypersomnia and behavioral or cognitive disturbances. Although prolonged emergence from general anesthesia and postoperative hypersomnia may occur in a patient with KLS, there is little information about the safe anesthetic management of these patients. We describe the case of a 22-year-old female previously diagnosed with KLS who was scheduled to have her third molars extracted under general anesthesia. Because the patient had symptoms of periodic hypersomnia and hyperphagia, the surgery was scheduled during a KLS crisis interval. General anesthesia was induced with propofol, remifentanil, and rocuronium, and maintained with desflurane and remifentanil. To prevent overuse of anesthetic agents, an electroencephalogram (EEG)-based depth of anesthesia monitor (SedLine; Masimo Corporation) was used intraoperatively. A neuromuscular monitor was also used to carefully titrate use of a neuromuscular blocking agent. After surgery, sugammadex was administered, and the patient quickly emerged within 10 minutes, as also confirmed by the EEG monitor. She had no KLS recurrence postoperatively. When anesthetizing patients with KLS, an EEG-based depth of anesthesia monitor and neuromuscular monitor may be warranted to ensure complete emergence from general anesthesia. In addition, elective surgery should be planned during crises intervals.

LMOD3 gene variant in familial periodic hypersomnolence.

INTRODUCTION: Kleine-Levin syndrome (KLS) is a rare and debilitating disorder presenting with periodic hypersomnolence, cognitive, psychiatric and behavioral disturbances. In the absence of biomarkers it can be difficult to diagnose. Rare LMOD3 variants in a family and in seven sporadic cases with KLS have been described. Here we report a patient and her family with an unclassified, familial, periodic central disorder of hypersomnolence (CDH) in whom the presence of a LMOD3 gene variant was assessed. CASE DESCRIPTION: The female patient presented since early adulthood with recurrent episodes of hypersomnolence. Over more than 20 years of follow-up the diagnoses of idiopathic hypersomnia, KLS and hypersomnia associated with a psychiatric condition were made. The family history is positive for periodic hypersomnolence and psychiatric conditions. The patient, her symptomatic mother and her asymptomatic sister carried a Proline for Histidine substitution at codon 552 of the LMOD3-gene. This variant was previously reported in two sporadic KLS patients and its frequency in the general population is below 0.02%. DISCUSSION: We report the association of periodic hypersomnia with a polymorphism of the LMOD3-gene in a patient with atypical KLS and a positive family history. Further research is needed to assess the pathological and predictive value of LMOD3 variants in KLS.

Treatment of central disorders of hypersomnolence: an American Academy of Sleep Medicine clinical practice guideline.

INTRODUCTION: This guideline establishes clinical practice recommendations for the treatment of central disorders of hypersomnolence in adults and children. METHODS: The American Academy of Sleep Medicine commissioned a task force of experts in sleep medicine to develop recommendations and assign strengths to each recommendation, based on a systematic review of the literature and an assessment of the evidence using the GRADE process. The task force provided a summary of the relevant literature and the quality of evidence, the balance of benefits and harms, patient values and preferences, and resource use considerations that support the recommendations. The AASM Board of Directors approved the final recommendations. RECOMMENDATIONS: The following recommendations are intended to guide clinicians in choosing a specific treatment for central disorders of hypersomnolence in adults and children. Each recommendation statement is assigned a strength ("strong" or "conditional"). A "strong" recommendation (ie, "We recommend…") is one that clinicians should follow under most circumstances. A "conditional" recommendation (ie, "We suggest…") is one that requires that the clinician use clinical knowledge and experience and strongly consider the individual patient's values and preferences to determine the best course of action. Under each disorder, strong recommendations are listed in alphabetical order followed by the conditional recommendations in alphabetical order. The section on adult patients with hypersomnia because of medical conditions is categorized based on the clinical and pathological subtypes identified in ICSD-3. The interventions in all the recommendation statements were compared to no treatment. 1: We recommend that clinicians use modafinil for the treatment of narcolepsy in adults. (STRONG). 2: We recommend that clinicians use pitolisant for the treatment of narcolepsy in adults. (STRONG). 3: We recommend that clinicians use sodium oxybate for the treatment of narcolepsy in adults. (STRONG). 4: We recommend that clinicians use solriamfetol for the treatment of narcolepsy in adults. (STRONG). 5: We suggest that clinicians use armodafinil for the treatment of narcolepsy in adults. (CONDITIONAL). 6: We suggest that clinicians use dextroamphetamine for the treatment of narcolepsy in adults. (CONDITIONAL). 7: We suggest that clinicians use methylphenidate for the treatment of narcolepsy in adults. (CONDITIONAL). 8: We recommend that clinicians use modafinil for the treatment of idiopathic hypersomnia in adults. (STRONG). 9: We suggest that clinicians use clarithromycin for the treatment of idiopathic hypersomnia in adults. (CONDITIONAL). 10: We suggest that clinicians use methylphenidate for the treatment of idiopathic hypersomnia in adults. (CONDITIONAL). 11: We suggest that clinicians use pitolisant for the treatment of idiopathic hypersomnia in adults. (CONDITIONAL). 12: We suggest that clinicians use sodium oxybate for the treatment of idiopathic hypersomnia in adults. (CONDITIONAL). 13: We suggest that clinicians use lithium for the treatment of Kleine-Levin syndrome in adults. (CONDITIONAL). 14: We suggest that clinicians use armodafinil for the treatment of hypersomnia secondary to dementia with Lewy bodies in adults. (CONDITIONAL). 15: We suggest that clinicians use modafinil for the treatment of hypersomnia secondary to Parkinson's disease in adults. (CONDITIONAL). 16: We suggest that clinicians use sodium oxybate for the treatment of hypersomnia secondary to Parkinson's disease in adults. (CONDITIONAL). 17: We suggest that clinicians use armodafinil for the treatment of hypersomnia secondary to traumatic brain injury in adults. (CONDITIONAL). 18: We suggest that clinicians use modafinil for the treatment of hypersomnia secondary to traumatic brain injury in adults. (CONDITIONAL). 19: We suggest that clinicians use modafinil for the treatment of hypersomnia secondary to myotonic dystrophy in adults. (CONDITIONAL). 20: We suggest that clinicians use modafinil for the treatment of hypersomnia secondary to multiple sclerosis in adults. (CONDITIONAL). 21: We suggest that clinicians use modafinil for the treatment of narcolepsy in pediatric patients. (CONDITIONAL). 22: We suggest that clinicians use sodium oxybate for the treatment of narcolepsy in pediatric patients. (CONDITIONAL). CITATION: Maski K, Trotti LM, Kotagal S, et al. Treatment of central disorders of hypersomnolence: an American Academy of Sleep Medicine clinical practice guideline. J Clin Sleep Med. 2021;17(9):1881-1893.

Treatment of central disorders of hypersomnolence: an American Academy of Sleep Medicine systematic review, meta-analysis, and GRADE assessment.

INTRODUCTION: This systematic review provides supporting evidence for the accompanying clinical practice guideline on the treatment of central disorders of hypersomnolence in adults and children. The review focuses on prescription medications with U.S. Food & Drug Administration approval and nonpharmacologic interventions studied for the treatment of symptoms caused by central disorders of hypersomnolence. METHODS: The American Academy of Sleep Medicine commissioned a task force of experts in sleep medicine to perform a systematic review. Randomized controlled trials and observational studies addressing pharmacological and nonpharmacological interventions for central disorders of hypersomnolence were identified. Statistical analyses were performed to determine the clinical significance of all outcomes. Finally, the Grading of Recommendations Assessment, Development and Evaluation (GRADE) process was used to assess the evidence for the purpose of making specific treatment recommendations. RESULTS: The literature search identified 678 studies; 144 met the inclusion criteria and 108 provided data suitable for statistical analyses. Evidence for the following interventions is presented: armodafinil, clarithromycin, clomipramine, dextroamphetamine, flumazenil, intravenous immune globulin (IVIG), light therapy, lithium, l-carnitine, liraglutide, methylphenidate, methylprednisolone, modafinil, naps, pitolisant, selegiline, sodium oxybate, solriamfetol, and triazolam. The task force provided a detailed summary of the evidence along with the quality of evidence, the balance of benefits and harms, patient values and preferences, and resource use considerations. CITATION: Maski K, Trotti LM, Kotagal S, et al. Treatment of central disorders of hypersomnolence: an American Academy of Sleep Medicine systematic review, meta-analysis, and GRADE assessment. J Clin Sleep Med. 2021;17(9):1895-1945.

Treatment of Kleine-Levin Syndrome With Intranasal Photobiomodulation and Methylene Blue.

Kleine-Levin syndrome (KLS) is a rare neuropsychiatric disorder, characterized by recurrent episodes of idiopathic hypersomnia, and cognitive and behavioral abnormalities, such as memory loss and child-like language. There is no definitive etiology for KLS; however, there are hypotheses of genetic predisposition, autoimmune mechanisms, and abnormal thalamic and hypothalamic functioning. Similarly, there is no definitive treatment for KLS as one method may be beneficial for one patient and not for another. We present a case of KLS in a patient who has no clinical improvement in symptoms with a variety of treatments. The parents of the patient agreed to attempt a trial of intranasal photobiomodulation (i-PBM) with red light, in combination with methylene blue (MB). The patient showed remission of the KLS episode following treatment with no further KLS episodes reported after treatment.