The RAS also inhibits the sleep-promoting ventrolateral preoptic area (VLPO), suppressing GABA, which in turn increases the activity of motor neurons and muscle tone. Narcolepsy is classified as follows based on clinical features:ĭuring normal wakefulness, orexin-containing neurons in the lateral hypothalamus increase the activity of the nuclei of the Reticular Activating System (RAS), which increases wake-promoting neurotransmitters in the cortex dopamine, norepinephrine, serotonin, and histamine inhibit REM and acetylcholine is increased in both wakefulness and REM. The mechanism of narcolepsy type 2 is less clear, but it is thought that it may be due to a similar but less severe loss of orexin neurons. Although a specific autoantibody that correlates with disease mechanism in narcolepsy has not yet been identified, this does strongly suggest that narcolepsy type 1 may be an autoimmune disease. Antibodies against streptococcal infections have also been associated with the onset of narcolepsy type 1. Additionally, there was an increase in the number of reported cases of narcolepsy in non-vaccinated patients after wild A(H1N1) pandemic influenza infection. The same adjuvant was, however, also used in Canada but the corresponding increase in reported cases did not occur there. In 2009 there was an increase in the number of cases of narcolepsy type 1 reported in Europe after receiving the European AS03-adjuvanted A(H1N1) pandemic influenza vaccine (Pandemrix) and it was initially thought that the immune response to the adjuvant might have been the cause of the disease. Some patients initially diagnosed with narcolepsy type 2 will develop cataplexy, indicating disease progression. Less commonly, trauma and tumors may result in narcolepsy. Current hypotheses include less destruction of orexin cells, impaired orexin receptor signaling, or an unknown mechanism. The cause of narcolepsy type 2 is not entirely clear. HLA haplotype DQB1*0602 is present in 95% of narcolepsy type 1 patients, but this is also present in about 20% of the general population without narcolepsy. The reason for this is not fully understood, but it is thought to be an autoimmune process possibly triggered by an infection. Importantly, management also needs to involve sleep hygiene advice, safety measures whenever applicable and guidance with regard to the social sequelae of cataplexy.Ĭataplexy Drop attacks Narcolepsy Pseudocataplexy Sodium oxybate Syncope.Narcolepsy type 1 occurs when nearly all of the neurons that contain orexin (also called hypocretin) are lost. Symptomatic treatment is possible with antidepressants and sodium oxybate.
#CATUABA NARCOLEPSY CATAPLEXY SERIES#
Over time, these severe symptoms evolve to the milder adult phenotype, and this pattern is crucial to recognize when assessing the outcome of uncontrolled case series with potential treatments such as immunomodulation. Cataplexy shows remarkable differences in childhood compared to adults, with profound facial hypotonia and complex active motor phenomena. Currently, the diagnosis of cataplexy is made almost solely on clinical grounds, based on history taking and (home) videos. Childhood narcolepsy, with its profound facial hypotonia, can be confused with neuromuscular disorders, and the active motor phenomenona resemble those found in childhood movement disorders such as Sydenham's chorea. They can be differentiated from cataplexy using thorough history taking, supplemented with (home)video recordings whenever possible. Cataplexy mimics include syncope, epilepsy, hyperekplexia, drop attacks and pseudocataplexy.
Next to narcolepsy, cataplexy can sometimes be caused by other diseases, such as Niemann-Pick type C, Prader Willi Syndrome, or lesions in the hypothalamic or pontomedullary region.
Moreover, childhood cataplexy differs from the presentation in adults, with a prominent facial involvement, already evident without clear emotional triggers ('cataplectic facies') and 'active' motor phenomena especially of the tongue and perioral muscles. The expression of cataplexy varies widely, from partial episodes affecting only the neck muscles to generalized attacks leading to falls. Although cataplexy is rare, its recognition is important as in most cases, it leads to a diagnosis of narcolepsy, a disorder that still takes a median of 9 years to be diagnosed. This review describes the diagnosis and management of cataplexy: attacks of bilateral loss of muscle tone, triggered by emotions and with preserved consciousness.
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