Kleine-Levin syndrome in a 10-year-old boy as the rare cause of hypersomnia

Hypersomnia in children and adolescence can be caused by various factors. The most frequent cause is chronically shortened sleep due to poor sleep hygiene. Sleep-related breathing disorders also lead to increased daytime fatigue. Recurrent phases of hypersomnia accompanied by abnormal behavior during these phases may indicate the Kleine-Levin syndrome.

We report on a 10-year-old boy who had displayed pronounced hypersomnia over a period of 3 months following an upper respiratory tract infection. He slept for up to 20 hours at a stretch and displayed clearly abnormal behavior such as lack of distance, largely offensive comments frequently with a sexual innuendo, etc. The patient was HLA-DQ2 positive, diagnosis otherwise normal. Symptoms improved noticeably within a week under therapy with Oxcarbazepine (OXC). No further abnormal behavior was observed. After a symptom-free year, OXC was withdrawn at the parents' request. A relapse occurred 5 months later during an infection. Symptoms again improved on OXC. The second hypersomnia phase lasted approx. 4 weeks. Following 1 week free of symptoms another hypersomnia phase of 5 days duration occurred during the Autumn holidays. Since then, the patient has been free of symptoms (6 week follow-up).

The Kleine-Levin syndrome is a rare disorder with periodic hypersomnia associated with abnormal behavior, perception disorder, frequent hyperphagia and hypersexuality. The cause is usually idiopathic. Infections are often cited as a trigger for an episode. Most patients are male and the syndrome usually begins during adolescence. The disorder is self-limiting, prognosis is poorer if the disorder is manifested before the age of 12, 50% of these patients still have symptoms after 25 years. There is no causal therapy, lithium and valproate had a certain preventive effect, and carbamazepine proved to be less effective.