Disturbed hypothalamic-pituitary axis in idiopathic recurring hypersomnia syndrome

Sleep disorders and the hypothalamus

As early as the 1920s, pathological studies of encephalitis lethargica allowed Von Economo to correctly identify hypothalamic damage as crucial for the profound associated sleep-related symptoms that helped define the condition. Only over the last 3 decades, however, has the key role of the hypothalamus in sleep-wake regulation become increasingly recognized. As a consequence, a close relation between abnormal sleep symptomatology and hypothalamic pathology is now widely accepted for a variety of medical disorders. Narcolepsy is discussed in some detail as the cardinal primary sleep disorder that is caused directly and specifically by hypothalamic pathology, most notably destruction of hypocretin (orexin)-containing neurons. Thereafter, various conditions are described that most likely result from hypothalamic damage, in part at least, producing a clinical picture resembling (symptomatic) narcolepsy. Kleine-Levin syndrome is a rare primary sleep disorder with intermittent symptoms, highly suggestive of hypothalamic involvement but probably reflecting a wider pathophysiology. ROHHAD (rapid-onset obesity with hypothalamic dysfunction, hypoventilation, and autonomic dysregulation) and Prader-Willi syndrome are also covered as hypothalamic syndromes with prominent sleep-related symptoms. Finally, sleep issues in several endocrine disorders are briefly discussed.

Kleine-Levin syndrome: clues to aetiology

Kleine-Levin syndrome (KLS) is the commonest recurrent sleep disorder, with a prevalence of 1-2 per million population. Clear diagnostic criteria are now defined, but effective treatment remains elusive. The significant body of published literature allows consideration of possible aetiological mechanisms, an understanding of which could guide the development of therapeutic strategies. Functional imaging studies have been inconclusive; although diencephalic abnormalities are a common finding, no consistent pattern has emerged, and these studies have not revealed the mechanism(s) underlying the development of the abnormalities detected. An autoimmune aetiology is consistent with the available data. In this review, we argue that, in order to further our understanding of KLS, there needs to be a co-ordinated international effort to standardise approaches to functional imaging studies, genetic analyses that specifically address the possibility of an autoimmune aetiology, and clinical trials of immunosuppressive therapies.

Kleine-Levin syndrome; An update and mini-review

Since 1962, when Critchley and Hoffman coined the term Kleine-Levin Syndrome (KLS) for the triad of hypersomnia, excessive eating and "often abnormal behavior" which they have observed in 11 adolescent boys, the number of patients recognized with this rare syndrome expanded, the spectrum of the clinical presentation, disease course, prognosis, gender specificity and the presence of familial cases were established. However, in spite of the progress made in neuroscience, the search for the cause, neuroanatomy, pathophysiology and drug treatment of KLS is still ongoing. In this mini-review we will describe in some detail the scientific efforts made to understand in depth the complex symptomatology of KLS and refer also to updated findings reached up till now.

The "Known Unknowns" of Kleine-Levin Syndrome: A Review and Future Prospects

Kleine-Levin syndrome (KLS) is a rare, homogeneous, debilitating sleep disorder characterized by episodic hypersomnia, cognitive impairment, and behavioral changes. The etiology, pathophysiology, and optimal management of KLS remain uncertain. We identify the 5 key areas requiring urgent attention: KLS immunopathogenesis studies, next-generation genetics, multimodal functional imaging, biomarker discovery, and clinical drug trials. A centralized registry of afflicted individuals must be established. Disease uniformity should make the identification of associated genetic or imaging biomarkers easier, but clinical efforts require laboratory-based research to model the disease and generate preclinical data for clinical translation.

Relationship between Kleine-Levin syndrome and upper respiratory infection in Taiwan

STUDY OBJECTIVES

In Kleine-Levin Syndrome (KLS), new episodes of hypersomnia are often preceded by an acute flu-like syndrome or upper airway infection 3 to 5 days before onset. This study investigated the relationship between the occurrence of mild upper respiratory tract infections (URIs) in the general population and the occurrence and seasonality and hypersomnic episodes in KLS patients.

DESIGN

This investigation was a longitudinal clinical study. Based on data obtained from the National Health Research Institutes between 2006 and 2007, the timing of hypersomnic episodes in 30 KLS patients were compared with calendar reports of URI events, and the results compared with age-matched general Taiwanese population.

MEASUREMENTS

Clinical symptoms, physical examination, polysomnographic recording, SPECT study, and laboratory tests affirming KLS during both periods of hypersomnic attack and non-attack were collected. Every symptomatic episode was then followed up. The cross-correlation function (CCF) and bivariate correlations analysis were performed to see the relationship between KLS and URIs.

RESULTS

A positive finding of CCF analysis and significant bivariate correlations were found between KLS episodes and URI in the general population (r = 0.456*). In onset of hypersomnia, significant correlations existed among "acute upper respiratory infections" (r = 0.446*), "acute bronchitis and bronchiolitis" (r = 0.462*), and "pharyngitis and nasopharyngitis" (r = 0.548*) subtypes of infections. A positive correlation between higher reports of symptomatic hypersomnia and URI also existed in a given season. A positive nonsignificant trend for "allergic rhinitis" (r = 0.400) was also found.

CONCLUSION

The agent behind URI or its consequence (such as fever) is associated with increased incidence of KLS episodes and may explain periodic symptomatic recurrences.

First attack of Kleine-Levin syndrome triggered by influenza B mimicking influenza-associated encephalopathy

Six days after the onset of influenza B symptoms, a 14-year-old Japanese boy presented with encephalopathy-like symptoms, somnolence, irritability, and childishness, which we first considered was an atypical type of influenza-associated encephalopathy because the infection symptoms disappeared by day 4. His encephalopathy-like symptoms gradually improved, although he had repetitive hypersomnia attacks. Owing to the patient's clinical presentation and normal interleukin-6 levels in the cerebrospinal fluid during the first period of hypersomnia, we diagnosed him with Kleine-Levin syndrome (KLS) triggered by influenza B. The preceding influenza infection was not only a diagnostic clue of KLS but also a diagnostic confounding factor.

Kleine-Levin syndrome: interface between neurology and psychiatry

We report the first episode of Kleine-Levin (KLS) syndrome in a 17-year-old male. The illness onset, clinical features, neuropsychological evaluation and polysomnographic recording are described. Typical symptoms hypersomnia, hyperphagia and sexual disinhibition were observed besides behavioral disturbances, polysomnographic and neuropsychological alterations. Behavioral disturbances similar to a manic episode including psychotic symptoms were relevant. The pharmacologic treatment included lithium, methylphenidate and risperidone. The introduction of risperidone aimed the control of psychotic symptoms and the persistent manifestations of hypersexuality after sleepiness control and to the best of our knowledge there are no other reports regarding risperidone use for KLS in the literature.

Kleine-Levin syndrome: a systematic review of 186 cases in the literature

Kleine-Levin syndrome (KLS) is a rare disorder with symptoms that include periodic hypersomnia, cognitive and behavioural disturbances. Large series of patients are lacking. In order to report on various KLS symptoms, identify risk factors and analyse treatment response, we performed a systematic review of 195 articles, written in English and non-English languages, which are available on Medline dating from 1962 to 2004. Doubtful or duplicate cases, case series without individual details and reviews (n = 56 articles) were excluded. In addition, the details of 186 patients from 139 articles were compiled. Primary KLS cases (n = 168) were found mostly in men (68%) and occurred sporadically worldwide. The median age of onset was 15 years (range 4-82 years, 81% during the second decade) and the syndrome lasted 8 years, with seven episodes of 10 days, recurring every 3.5 months (median values) with the disease lasting longer in women and in patients with less frequent episodes during the first year. It was precipitated most frequently by infections (38.2%), head trauma (9%), or alcohol consumption (5.4%). Common symptoms were hypersomnia (100%), cognitive changes (96%, including a specific feeling of derealization), eating disturbances (80%), hypersexuality (43%), compulsions (29%), and depressed mood (48%). In 75 treated patients (213 trials), somnolence decreased using stimulants (mainly amphetamines) in 40% of cases, while neuroleptics and antidepressants were of poor benefit. Only lithium (but not carbamazepine or other antiepileptics) had a higher reported response rate (41%) for stopping relapses when compared to medical abstention (19%). Secondary KLS (n = 18) patients were older and had more frequent and longer episodes, but had clinical symptoms and treatment responses similar to primary cases. In conclusion, KLS is a unique disease which may be more severe in female and secondary cases.

Photosensitivity during the hypersomnic phase in a patient with Kleine-Levin syndrome

The case of an adolescent with Kleine-Levin syndrome is presented who exhibited a consistent and predictable photoparoxysmal self-limited response to intermittent photic stimulation during all relapses of his hypersomnic phase. A possible cause of this association that has not been previously reported is speculated based on observations concerning the two disorders.

Recurrent hyper- and hyposomnia: a new diagnostic entity? Polysomnographic findings and a 30-year follow-up

OBJECTIVES

This study reports on the sleep evaluation and follow-up of a professional woman who, in her 30s and 40s, had a decade of severe episodic fluctuations in the length of her sleep (12 vs. 4 h).

BACKGROUND

Severe psychogenic fluctuations in the duration of sleep have not previously been described except in bipolar disorders.

METHODS

Psychological and medical history and a total of 29 polysomnogram nights are presented, as well as a 30-year follow-up interview.

RESULTS

Long sleep episodes (>10 h) were characterized by excessive stage 1 sleep and a stage we called 'very light sleep' (over 50% alpha waves mixed with 5-10% delta waves). Long sleeps were also associated with hyperphagia and hypersexuality. Short sleeps (<4 h) emphasized delta and REM sleep. Sleep normalized spontaneously after about a decade of severe fluctuations.

CONCLUSIONS

In this patient, the recurrent hypersomnia/hyposomnia episodes may have been based mainly on psychiatric factors.

Neuropsychological sequelae in Kleine-Levin syndrome: case report

Kleine-Levin syndrome is characterized by periodic hypersomnia, hyperphagia, sexual disinhibitions and behavioral disturbances. The prognosis is generally benign, with normal cognitive and social functions after the episodes. We describe a typical case of Kleine-Levin syndrome associated with apparent academic decline, neuropsychological sequelae and personality alterations after the second episode of the illness. Further research in the natural history of Kleine-Levin syndrome is needed, for example, to determine whether early intervention would improve long-term prognosis.

The Kleine-Levin syndrome. Report of a case and review of the literature

Kleine-Levin syndrome is a rare self-limited disorder which usually affects adolescent males and is characterized by episodic hypersomnia, increased appetite, and behavioral/psychiatric disturbances. Individuals are normal between the attacks. The case of an adolescent boy is presented who suffered from recurrent sleepiness, hyperphagia, and behavioral disturbances such as rocking, punching and pacing, and was originally misdiagnosed as suffering from encephalitis. Before the diagnosis of Kleine-Levin was given, the patient underwent unnecessary investigations and treatment which, in turn, complicated his clinical condition both physically as well as psychologically. In the course of five years he had four such episodes which appeared to have progressively milder manifestations. Between episodes he was normal. It is important that the diagnosis is suspected early, especially in adolescent males who present with recurrent episodes of somnolence, increased appetite, and abnormal behavior, since it most often represents a benign and self-limited entity and does not warrant extensive investigations or treatment. It is also important to distinguish this syndrome from more serious organic and psychiatric diseases with more serious prognoses. The differential diagnosis of this syndrome is discussed and a review of the literature is presented including evidence and hypotheses regarding its pathophysiology.

Kleine-Levin syndrome and Parkinsonian symptoms--a case report

We report the case of a 54-year-old male patient, who developed the symptoms of Kleine-Levin syndrome (KLS) at the age of fifty. Four years later Parkinsonian symptoms (PS) appeared. The possible relationship between both KLS and PS, e.g. regarding neuroendocrinological similarities, will be discussed to explain the subsequent onset of PS after the manifestation of KLS in this patient.

Case study: hypersomnolence and precocious puberty in a child with pica and chronic lead intoxication

The limited literature on hypersomnolence suggests that it is a poorly defined symptom associated with a spectrum of disorders from monosymptomatic hypersomnolence to the Kleine-Levin syndrome. These disorders often herald an organic central nervous system syndrome. Recent evidence suggests a frequent association between these disorders and hypothalamic dysfunction, which itself may be caused by a variety of factors. This case study of a patient with persistent hypersomnolence, hypothalamic dysfunction (in the form of precocious puberty), pica, and chronic lead intoxication strengthens the association between hypersomnolence and hypothalamic dysfunction and suggests a heretofore unreported cause of hypothalamic dysfunction in humans.

Treatment of recurrent hypersomnia with methylcobalamin (vitamin B12): a case report

A 32 year old male patient suffered from recurrent hypersomnia for 12 years was successfully treated with vitamin B12. Episodes of hypersomnia lasting a few days occurred repeatedly a few times each year. Furthermore, the frequency of episodes had increased during the last 2 years. During the administration of vitamin B12, the patient had no episodes of hypersomnia for 6 months. In addition, he did not have any episodes during a follow-up observation period of 17 months after cessation of the treatment. Thus, this case suggests that vitamin B12 may be effective for preventing recurrent hypersomnia.