title: Cataplexy--clinical aspects, pathophysiology and management strategy.
abstract: Cataplexy is the pathognomonic symptom of narcolepsy, and is the sudden uncontrollable onset of skeletal muscle paralysis or weakness during wakefulness. Cataplexy is incapacitating because it leaves the individual awake but temporarily either fully or partially paralyzed. Occurring spontaneously, cataplexy is typically triggered by strong positive emotions such as laughter and is often underdiagnosed owing to a variable disease course in terms of age of onset, presenting symptoms, triggers, frequency and intensity of attacks. This disorder occurs almost exclusively in patients with depletion of hypothalamic orexin neurons. One pathogenetic mechanism that has been hypothesized for cataplexy is the activation, during wakefulness, of brainstem circuitry that normally induces muscle tone suppression in rapid eye movement sleep. Muscle weakness during cataplexy is caused by decreased excitation of noradrenergic neurons and increased inhibition of skeletal motor neurons by γ-aminobutyric acid-releasing or glycinergic neurons. The amygdala and medial prefrontal cortex contain neural pathways through which positive emotions probably trigger cataplectic attacks. Despite major advances in understanding disease mechanisms in cataplexy, therapeutic management is largely symptomatic, with antidepressants and γ-hydroxybutyrate being the most effective treatments. This Review describes the clinical and pathophysiological aspects of cataplexy, and outlines optimal therapeutic management strategies.
authors.affiliation: Department of Neurology, INSERM U1061, University of Montpellier, Montpellier 34295, France.
authors.forename: Yves
authors.initials: Y
authors.lastname: Dauvilliers
authors.affiliation: Neurobiology Research 151A3, University College Los Angeles, Veterans Administration Greater Los Angeles Healthcare System, 16111 Plummer Street, North Hills, CA 91343, USA.
authors.forename: Jerry M
authors.initials: JM
authors.lastname: Siegel
authors.affiliation: Department of Neurology, INSERM U1061, University of Montpellier, Montpellier 34295, France.
authors.forename: Regis
authors.initials: R
authors.lastname: Lopez
authors.affiliation: Centre for Brain Sciences, Department of Cell and Systems Biology, University of Toronto, Toronto, ON M4X 1H7, Canada.
authors.forename: Zoltan A
authors.initials: ZA
authors.lastname: Torontali
authors.affiliation: Centre for Brain Sciences, Department of Cell and Systems Biology, University of Toronto, Toronto, ON M4X 1H7, Canada.
authors.forename: John H
authors.initials: JH
authors.lastname: Peever
mesh_terms: D000818:Animals; D001921:Brain / Q000473:pathology*; D002385:Cataplexy / Q000175:diagnosis / Q000503:physiopathology / Q000628:therapy; D004569:Electroencephalography; D006801:Humans; D019964:Mood Disorders / Q000209:etiology; D018908:Muscle Weakness / Q000209:etiology; D009410:Nerve Degeneration / Q000209:etiology; D015835:Ocular Motility Disorders / Q000209:etiology