Central Disorders of Hypersomnolence

Kleine-Levin Syndrome

Background

Kleine-Levin syndrome (KLS) is a sleep disorder that includes waxing and waning episodes of severe sleepiness during which a person has difficulty with thinking, behavior, and psychiatric issues. These episodes also include very long sleep—up to 16 to 20 hours per day. KLS usually occurs for the first time after an infection or alcohol use during the teenaged years and is twice as common in males as in females.

Epidemiology

KLS is a very rare condition, affecting 1 or 2 of every 1 million people.

Diagnosis

Five criteria must be met to make a diagnosis of KLS.5

  • The person has at least 2 episodes of long sleep and excessive sleepiness, each of which lasts from 2 days to 5 weeks.
  • The episodes usually occur more than once a year and at least every 18 months.
  • Between episodes, the person has normal alertness, cognitive function, behavior, and mood.
  • During the episodes, the person has to have at least 1 of these symptoms
  • Cognitive dysfunction
  • Altered perception
  • Eating disorder
  • Disinhibited behavior
  • No drug or medication or other untreated sleep, medical, psychiatric, or neurologic disorder better explains the symptoms.
Hypersomnia due to a medical disorder

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5. American Academy of Sleep Medicine. International Classification of Sleep Disorders. Darien, IL: American Academy of Sleep Medicine, 3rd ed.; 2014.

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