The Special Case of KLS
What is Kleine-Levin Syndrome?
Kleine-Levin Syndrome (“KLS”) is a rare sleep disorder characterized by recurrent episodes of hypersomnia lasting one to 3 weeks, associated with behavioral/cognitive disturbances, megaphagia and, more rarely, sexual disinhibition. These episodes alternate from periods without any symptoms and normal sleep & behavior lasting months to years. KLS episodes are so intense that the affected patient typically cannot work or do anything during episodes. It is not uncommon for patients to be hospitalized as encephalopathic during the first episode, but as all tests are normal and the patient improves, the diagnosis is only made when it reoccurs a second time.
What do we know about KLS?
KLS primarily strikes adolescents and is self-limiting; cessation of episodes typically occurs in early adult life. It can be very disruptive to the life and study of these patients. All diagnostic test results on KLS patients to date, including brain imagery, EEG, serum virus titers, and CSF examination, have been normal, although recent research in our lab suggest a panel of protein measured in blood or CSF could help the diagnosis. Imaging studies suggest that parts of the brain such as the thalamus, hypothalamus and patchy areas in the cortex are inactivated during episodes, explaining symptoms. Recent genetic studies indicate an overlap with circadian problems and bipolar disorder. Our center is always interested in recruiting patients with KLS for various research protocols and collaborates closely with the KLS foundation to find a solution for these patients. Understanding KLS may help understand the complex relationship of hypersomnia with mood disturbances.
How is Kleine-Levin syndrome diagnosed and treated?
The diagnosis of KLS is purely clinical. Medical causes such as epilepsy, metabolic abnormalities, genetic diseases, or frank psychiatric disorders that can mimic symptoms must be excluded. In most cases, once diagnosed, we suggest that careful observation by parents or relatives of the patient during episodes so that no harm occurs is the best course of action. Accommodation of work/school is needed during episodes. The disease improves spontaneously in adulthood. Some cases are very severe, intermediary between KLS and idiopathic hypersomnia, and can benefit from lithium and other medications.