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Kleine-Levin Syndrome or KLS (also known as Sleeping Beauty Syndrome) is a neurological disorder characterized by recurring periods of excessive amounts of sleeping and eating. At the onset of an episode the patient becomes 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. They also experience confusion, disorientation, complete lack of energy (lethargy), and lack of emotions (apathy). Individuals are not able to attend school or work or care for themselves. Most are bedridden, tired, and uncommunicative even when awake.
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.
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 disfunction.
The cause of Kleine-Levin syndrome is not known. Thus, family support and education are the best management currently available.
Hypersomnia is a primary symptom of KLS, and is present in all subjects. Subjects are often treated initially for a sleeping disorder. During a KLS episode, subjects often spend 18 hours a day asleep. Another defining symptom of KLS is an altered mental state during the episode. Subjects are hard to arouse from this sleep, and are irritable or aggressive when prevented from sleeping.
Diagnosis of KLS is very difficult since there are no symptoms that allow for a positive diagnosis. KLS is instead a diagnosis of exclusion, where a doctor must first eliminate a long list of other conditions that could mimic the symptoms. Because hypersomnia is the primary symptom, many patients are initially treated for a sleeping disorder. Potential KLS patients are often referred to an endocrinologist early on to check for metabolic problems including diabetes and hypothyroidism. Several other disorders can also mimic KLS symptoms, but many can be positively diagnosed by MRI—including ones caused by a lesion, tumor, or inflammation. Multiple sclerosis also has neurological components that can mimic the symptom profile for KLS.