Kleine Levin Syndrome Foundation
What is Kleine-Levin Syndrome?
Kleine-Levin Syndrome (KLS) is a rare and complex neurological disorder characterized by periods of excessive amounts of sleep and altered behavior. The disorder strikes adolescents primarily. At the onset of an episode the patient becomes progressively drowsy and sleeps for most of the day and night (hypersomnolence), waking only to eat or go to the bathroom. When awake, the patient’s whole demeanor is changed, often appearing “spacey” or childlike. When awake he experiences confusion, disorientation, complete lack of energy (lethargy), and lack of emotions (apathy). Most patients report that everything seems out of focus, and that they are hypersensitive to noise and light. In some cases, food cravings (compulsive hyperphagia) are exhibited. Instances of uninhibited hypersexuality during an episode have also been reported.
Kleine-Levin Syndrome episodes are cyclical. When present, KLS symptoms persist for days, weeks or even months, during which time all normal daily activities stop. Individuals are not able to attend school, work or care for themselves. Most are bedridden, tired and uncommunicative even when awake. Not everyone affected by KLS exhibits all of the symptoms described above.
Affected individuals may go for a period of weeks, months or even years without experiencing any symptoms, and then they reappear with little warning. In between episodes those diagnosed with KLS appear to be in perfect health with no evidence of behavioral or physical dysfunction. However they function daily with the frightful reality that they could become sick again at any moment. KLS episodes may continue to reoccur for a decade or longer with devastating effects on the adolescent’s life and family. KLS robs children and young adults of big pieces of their lives, one agonizing episode at a time.
The mean diagnostic delay for proper KLS diagnosis is four years, causing undue suffering to patients and families. The cause of Kleine-Levin Syndrome is not known.
Are My Symptoms Consistant with KLS?
The following KLS definition was developed by the International Classification of Sleep Disorders (2005)
While the definition below captures the symptoms experienced by a vast majority of KLS cases, like with any medical condition there are atypical cases or outliers which do not fall within the classic definition. The length of episodes and period of time between episodes in some cases are known to be outside of the periods noted in this definition. The lack of a known medical test to confirm KLS, cause for its onset or its remission means that all of the information available regarding KLS is based on observations of suspected cases. Further, the rarity of illness results in a limited sample size which means that as more data is gathered it is possible that we will find that the definition and “typical” symptoms will shift.
A KLS patient would have symptom A, one or more of the B symptoms, and the pattern described in C.
A. Recurrent episodes of severe hypersomnia (2-31 days)
B. Plus one or more of the associated features :
1. Cognitive abnormalities such as feeling of unreality,
2. Abnormal behavior such as irritability, aggression,
3. Binge eating
C. Interspersed with long periods of normal sleep, cognition,