Secondary Narcolepsy in Children.

Abstract

Secondary narcolepsy occurs as a consequence of lesions involving the hypothalamic region that subserve wakefulness. Although observations on the characteristics of secondary narcolepsy have been published in adults, information on this topic in children is sparse. This is a retrospective study of characteristics and outcome of secondary narcolepsy in children. The medical records of 10 children with this condition at Mayo Clinic, Rochester, were reviewed. Characteristics of the underlying neurologic disorder, narcolepsy subtype, multiple sleep latency tests, medications used and outcome were extracted. Age at diagnosis of narcolepsy was between 6 and 17 years. Five of 10 patients had onset of excessive sleepiness within 1 year of diagnosis of the primary neurologic disorder. Six of 10 patients had type 1 narcolepsy (with cataplexy) whereas 4/10 had type 2 (without cataplexy). The clinical course was variable, with 8/10 continuing to require treatment for sleepiness at a mean period 6.6±6.2 years after diagnosis. One patient with narcolepsy type 1 due to Niemann Pick type C disease had died. One patient with narcolepsy type 2 due to craniopharyngioma had spontaneous remission of sleepiness. The 5/10 patients surviving with narcolepsy type 1 have continued to require pharmacotherapy for both sleepiness and cataplexy. This study draws attention to an important chronic sequel of childhood brain lesions that has variable, etiology-specific outcome. The rare occurrence of spontaneous resolution of childhood narcolepsy symptoms, not previously described, is also discussed.