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At a glance

This is a cyclic disorder affecting the behavior during adolescence and characterized by diurnal hypersomnolence (up to 20 hours/day), compulsive hyperphagia, coprolalia, copropraxia, and abnormally uninhibited sexual drive. The disorder primarily affects adolescent males. When awake, affected individuals are irritable, lethargic, and apathic. Some experience hallucinations. Individuals with Kleine-Levin Syndrome may have episodes that last for a few days or up to several weeks. Episodes occur approximately 2 to 12 times per year.


Critchley Syndrome; Familial Hibernation Syndrome; Hypersomnia-Bulimia Syndrome; Kleine-Levin-Critchley Syndrome; Periodic Somnolence and Morbid Hunger Syndrome.


Approximately 500 cases have been reported in the medical literature. Males appear to be affected three times as often as females. The peak of the disease is around 16 years of age.

Genetic inheritance

Autosomal dominant inheritance. Human leukocyte antigen (HLA)-DQB1*0201 allele frequency was significantly increased in patients with Kleine-Levin Syndrome.


It is indicated to use magnetic resonance imaging of the brain to eliminate other possible conditions. Overnight video-synchronized polysomnography and multiple sleep latency tests must eliminate narcolepsy. Epworth Sleepiness Scale score (studies eight situations where tendency to become sleepy is assumed. Zero is none and level 3 determines the chance to become sleepy. The sum of all eight conditions will give a number between 0 and 24) must be used to confirm the diagnosis.


Unknown. Hypotheses include a hypothalamic dysfunction and abnormalities in the central serotonin and dopamine metabolism. Several clinical symptoms also suggest an underlying autoimmune process.

Clinical aspects

Episodic attacks of aberrant behavior with normal behavior between episodes. Attacks may last for several weeks and are characterized by hypersomnia, hyperphagia with subsequent vomiting, hallucinations with disorientation, increased sexual drive, and mood depression. Attacks may be precipitated by infections, head trauma, or alcohol consumption.

Anesthetic considerations

Repeated episodes of bulimia may lead to electrolyte disorders. Mallory-Weiss tears can result from repetitive vomiting, which may lead to anemia from chronic upper gastrointestinal blood loss.

Pharmacological implications

These patients may be treated with amphetamines or lithium. Their interference with anesthetic drugs should be kept in mind.

Other condition to be considered

  • Narcolepsy: Sleep disorder characterized by abnormal sleepiness during the day and sudden cataplexy (muscle weakness), lethargy, hallucinations, paralysis while sleeping, and night insomnia. Excessive daytime sleepiness is usually the first symptom of narcolepsy. The onset of symptoms is seen during adolescence. The exact cause is unknown.


Arnulf  I, Zeitzer  JM, File  J,  et al: Kleine-Levin syndrome: A systematic review of 186 cases in the ...

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