Hypocretin (orexin) and melatonin values in a narcoleptic-like sleep disorder after pinealectomy.

Narcolepsy secondary to other neurologic processes has been recently associated with hypocretin (orexin) deficiency. We present a patient who developed a narcoleptic-like sleep disorder after receiving treatment for a choroid plexus carcinoma of the pineal gland. She underwent a pinealectomy, chemotherapy, and radiation treatment. The primary features of this condition were excessive daytime sleepiness, sleep paralysis and hypnagogic hallucinations. Increased percentage of rapid eye movement (REM) sleep and sleep onset REM periods were seen during the multiple sleep latency test. Circadian rhythmicity was preserved for melatonin and cortisol. She was negative for human leukocyte antigen DQB1*0602 and had a detectable cerebrospinal fluid hypocretin level (518 pg/ml). We emphasize that the narcoleptic-like disorder likely resulted from the surgical intervention or radiation therapy. Her symptoms are caused by an unknown mechanism unrelated to hypocretin depletion which merits more research.