What are the other Names for this Condition? (Also known as/Synonyms)

• Familial Hibernation (Kleine-Levin) Syndrome
• Kleine Levin Critchley Syndrome
• Sleeping Beauty Syndrome

What is Kleine-Levin Syndrome? (Definition/Background Information)

• Kleine-Levin syndrome (KLS) is a very uncommon sleep disorder. In addition to sleepiness, individuals also have compulsive overeating and hyper-sexuality
• Hypersomnia means excessive sleepiness. Even after taking long naps, the individual does not feel rested. There are two types of hypersomnia:
  • The first type is called primary hypersomnia, also called idiopathic hypersomnia
  • The second type is called recurrent hypersomnia, also called primary recurrent hypersomnia
• In primary hypersomnia, the excessive sleepiness happens over a period of many months, or sometimes, even for many years. The excessive sleepiness occurs without periods of normality.  In the recurrent type of hypersomnia the symptoms last for many years, but the individual is symptom-free for a period of time (which can last up to months), between episodes of hypersomnia. This normal sleep period between periods of excessive sleep is very characteristic of Kleine-Levin Syndrome
• Excessive sleep occurs during the day, which is called excessive daytime sleepiness. Due to this excessive daytime sleepiness, the individual is forced to take naps during the day, which interrupts one’s daily routine. Also, a frequent nap during the day does not refresh the individual
• KLS is a very unusual disorder. The signs and symptoms begin slowly. In some individuals the symptoms may either gradually worsen over a period of time, or they may get better over time

Who gets Kleine-Levin Syndrome? (Age and Sex Distribution)

• Kleine-Levin syndrome is rare disorder. The signs and symptoms usually start during the teens or at around young adulthood
• Both males and females can be affected by KLS, though it predominantly affects males; over two-thirds of the cases occur in males

What are the Risk Factors for Kleine-Levin Syndrome? (Predisposing Factors)

Risk factors commonly associated with Kleine-Levin Syndrome include:

• Family history of KLS
• Severe brain damage such as due to a head trauma 
• Severe depression
• Liver failure due to excessive alcohol intake
• Bipolar disorder
• Infections such as infectious mononucleosis

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases one's chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Kleine-Levin Syndrome? (Etiology)

The exact cause for Kleine-Levin syndrome (KLS) is unknown.

• It has been postulated that the cause of hypersomnia may be due to brain dysfunction in chemical substances
• In the brain there are chemical substances called neurotransmitters. Normal brain activity occurs due to a fine balance between many different types of neurotransmitters
• Sometimes, there is an imbalance of neurotransmitters in the brain. In Kleine-Levin Syndrome, there is hyperactivity of a receptor called GABA receptors

What are the Signs and Symptoms of Kleine-Levin Syndrome?

Kleine-Levin Syndrome has a recurring, cyclical pattern of symptoms. The symptoms tend to occur every 3-4 months. Each time an individual gets the symptoms, they tend to last between 1-2 weeks. In between the episodes of symptoms, the individual has a normal sleep pattern. 

The signs and symptoms of KLS may include:

• Difficulty in sleeping at night, difficulty in waking up from a long sleep
• Not feeling rested after a sleep
• Personality problems such communication with others
• Hypersensitive to light or noise
• Feeling of derealization
• Hyper-sexuality
• Depression
• Impulsive behavior
• Lack of energy
• Hallucinations and depersonalization
• Increased stressed and anxiety
• Excessive eating
• Poor work performance
• Memory problems
• Slurred speech

Sometimes, after waking up from a long sleep, the individual feels irritable and disoriented. This is called sleep drunkenness.

How is Kleine-Levin Syndrome Diagnosed?

Kleine-Levin Syndrome is a diagnosis of exclusion. The diagnosis is usually arrived at after a thorough medical examination for possible causes of hypersomnia. A diagnosis of KLS is made if an individual has excessive sleep for a period of more than a month that significantly affects the quality of life.

• A good clinical history is very important and helps in arriving at an accurate diagnosis of KLS
• Possible cause for the symptoms, such as medications and other medical conditions causing excessive sleep, should be ruled out
• Conditions resulting in excessive sleep may include:
  • Menstrual-related hypersomnia
  • Viral infection such infectious mononucleosis and atypical viral pneumonia.
• Blood test to test for kidney and liver failure
• A sleep study may also help with diagnosis
• CT scan of head and MRI of the brain to rule out any brain damage

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Kleine-Levin Syndrome?

The possible complication of Kleine-Levin Syndrome includes severe damage to the quality of life.

How is Kleine-Levin Syndrome Treated?

There is no definitive treatment available for Kleine-Levin Syndrome.

• The healthcare professionals may treat the symptoms arising from the disorder
• Sometimes, medication to keep the individual alert maybe prescribed; though this may not always work
• Staying away from caffeinated drinks and alcoholic beverages help in decreasing the symptoms

How can Kleine-Levin Syndrome be Prevented?

• Currently, there are no known measures to prevent Kleine-Levin Syndrome, since the exact cause of the condition is unknown
• No genetic markers of the condition have been identified

What is the Prognosis of Kleine-Levin Syndrome? (Outcomes/Resolutions)

• The prognosis of Kleine-Levin Syndrome depends upon the severity of the symptoms. The prognosis is excellent in individuals who have mild symptoms
• On the other hand, for individuals with severe symptoms, the prognosis is guarded. Severe cases can result in overweight conditions due to overeating. Obesity, due to this, can result in many other health issues
• In some cases, the symptoms may disappear completely over a period of time

Additional and Relevant Useful Information for Kleine-Levin Syndrome:

The following DoveMed website link is a useful resource for additional information:

https://www.dovemed.com/healthy-living/emotional-well-being/