The Kleine-Levin Syndrome

The essential clinical criterion of Kleine-Levin syndrome (KLS) is recurrent episodes of hypersomnia. Patients have to experience at least one of the following symptoms during the episodes: (1) cognitive disturbances, (2) megaphagia, (3) hypersexuality, (4) irritability or odd behavior. Recent imaging studies have shown involvement of the thalamus, and raise the question of persistent hypoperfusion in some brain areas during the asymptomatic period. There is no clear etiology for the syndrome, although some more frequent HLA genotypes suggest a possible auto-immune mediation of the disease. No treatment as been shown systematically to improve KLS despite many trials with drugs. No therapeutic recommendation can be made today.