Kleine-Levin Syndrome
A rare disorder characterized by recurring episodes of excessive sleep, altered behavior, and a reduced understanding of the world, interspersed with periods of normal function.
What is Kleine-Levin Syndrome?
Kleine-Levin Syndrome (KLS) is a rare and complex neurological disorder characterized by recurring episodes of excessive sleep (hypersomnia), cognitive disturbances, and behavioral changes. During episodes, patients may sleep up to 20 hours per day and experience altered perception of reality, compulsive eating, and disinhibited behavior. Episodes typically last days to weeks and recur over years. Between episodes, patients are completely normal with no residual symptoms. The disorder most commonly begins in adolescence and often improves or resolves in adulthood.
Prevalence
KLS is very rare, affecting approximately 1-5 per million people. It is about 2-3 times more common in males than females. Onset is typically in adolescence (median age 15), though it can occur at any age. Jewish individuals appear to have higher prevalence, suggesting possible genetic factors. Episodes typically decrease in frequency and severity over 8-14 years, with many patients eventually experiencing complete resolution.
Causes
The exact cause of KLS is unknown. Current theories include: autoimmune or post-infectious inflammation affecting the hypothalamus and thalamus, genetic predisposition (HLA-DQB1*02 association), dysfunction of the brain's arousal and regulatory centers, and possible viral triggers (about 70% of patients report infection before first episode). The hypothalamus, which regulates sleep, appetite, and behavior, appears to be a key area of dysfunction.
Symptoms
Prolonged sleep (hypersomnia)
During episodes, patients sleep 15-21 hours per day, waking only to eat and use the bathroom. They are difficult to arouse and quickly fall back asleep.
Cognitive dysfunction
Confusion, feeling as if in a dream, difficulty with attention, memory impairment, and slowed thinking characterize episodes. Patients may have difficulty with speech.
Derealization
The world feels unreal or dreamlike. Patients describe feeling detached from themselves and their environment.
Compulsive eating (hyperphagia)
About 75% of patients experience excessive eating, particularly craving sweets, during episodes. They may eat everything available without satiation.
Hypersexuality
Inappropriate sexual behaviors or disinhibition occur in about 50% of patients during episodes, more commonly in males.
Mood changes
Apathy, depression, childish behavior, and irritability are common during episodes. Some patients become aggressive.
Complete normalcy between episodes
Between episodes, patients have no symptoms and function completely normally. This periodicity is a hallmark of the disorder.
Diagnosis
Self-Assessment Questions
If you answer yes to any of these questions, consider consulting a sleep specialist:
- 1Have you experienced distinct episodes where you sleep 15+ hours per day for days or weeks, then return to completely normal?
- 2During these episodes, do you feel confused, dreamlike, or disconnected from reality?
- 3Do you have uncontrollable urges to eat during episodes?
- 4Did your first episode occur in your teenage years, possibly after an illness?
- 5Between episodes, do you feel and function completely normally?
- 6Have episodes recurred multiple times over months or years?
Diagnosis is clinical, based on the characteristic pattern of recurring episodes with hypersomnia and cognitive/behavioral changes, with complete normalcy between episodes. Other causes must be excluded.
Clinical History
Detailed documentation of episode characteristics, duration, frequency, and symptoms is the primary diagnostic tool. The pattern of complete normalcy between episodes is key.
Brain Imaging (MRI)
MRI is typically normal in KLS but is performed to rule out other causes such as tumors, encephalitis, or stroke.
EEG
Electroencephalogram may show generalized slowing during episodes but is typically normal between episodes. Helps rule out epilepsy.
Lumbar Puncture
Cerebrospinal fluid analysis may be performed to rule out infectious or inflammatory causes, particularly during first episode.
Toxicology Screen
Drug testing helps exclude substance-induced states that can mimic KLS symptoms.
SPECT/PET Imaging
Research studies show decreased blood flow/metabolism in thalamus and hypothalamus during episodes, but these tests are not routinely available.
Treatment
There is no proven treatment to prevent or shorten KLS episodes. Management is supportive during episodes, with some medications tried to prevent recurrences. The prognosis is generally favorable as most cases eventually resolve.
Supportive Care During Episodes
Patients need supervision and support during episodes. They should not drive, attend school, or work. Safety monitoring is important given altered judgment.
Lithium
The most commonly used preventive treatment, lithium may reduce episode frequency and duration in some patients, though evidence is limited.
Antiepileptic Medications
Valproate and carbamazepine have been tried for prevention with variable success.
Stimulants
Amphetamines or modafinil during episodes may help with wakefulness but typically don't affect cognitive symptoms. They don't prevent episodes.
Amantadine
Some reports suggest amantadine may help during acute episodes or as preventive therapy.
Lifestyle Adjustments
- •Learn to recognize prodromal symptoms that may signal an upcoming episode
- •Create a safe environment for episodes (someone to supervise, no driving)
- •Inform school or work about the condition and need for absences during episodes
- •Avoid triggers when possible (some patients identify specific triggers)
- •Maintain good general health to potentially reduce episode frequency
- •Keep a diary of episodes to track patterns
- •Connect with KLS support organizations and other families
Patient Support Resources
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