Narcolepsy with cataplexy is caused by a selective loss of hypocretin-producing neurons, but narcolepsy can also result from hypothalamic and rostral brainstem lesions.
We describe a 38-year-old woman with severe daytime sleepiness, internuclear ophthalmoplegia, and bilateral delayed visual evoked potentials. Her multiple sleep latency test results demonstrated short sleep latencies and 4 sleep-onset rapid eye movement sleep periods, and her cerebrospinal fluid contained a low concentration of hypocretin. Magnetic resonance imaging showed T2 and fluid-attenuated inversion recovery hyperintensity along the walls of the third ventricle and aqueduct, which are consistent with acute disseminated encephalomyelitis.
After treatment with steroids, this patient's subjective sleepiness, hypersomnia, and hypocretin deficiency partially improved.
Autoimmune diseases such as acute disseminated encephalomyelitis can produce narcolepsy. Most likely, this narcolepsy is a consequence of demyelination and dysfunction of hypocretin pathways, but direct injury to the hypocretin neurons may also occur.