A case report of REM sleep behavior disorder, Behcet’s disease, Sjogren’s syndrome and cognitive dysfunction

Background Behcet's disease and Sjogren's syndrome is an autoimmune disorder from which many systems of the body can suffer. Here we reported a patient with a history of Behcet's disease and Sjogren's syndrome in which REM sleep behavior disorder (RBD) was then detected by polysomnographic (PSG) monitoring.Case presentation A 68-year-old male patient with a history of Behcet's disease and Sjogren's syndrome was diagnosed with RBD by clinical examination and video-PSG, and he also underwent a multiple sleep latency test and cerebral magnetic resonance imaging. The patient had a history of Behcet's disease for 20 years and Sjogren's syndrome for 2 years. The cerebral magnetic resonance imaging also suggested cerebral demyelination and mild cortical atrophy, with cognitive dysfunction by a score of 28 on the mini-mental state examination (MMSE) and a score of 22 on the Montreal cognitive assessment (MoCA).Conclusion RBD is common in the elderly population and is significantly related to α-synucleinopathy. Combining the decline in neuro-cognition and mild cortical atrophy, presentation of RBD in this patient could indicate an underlying α-synucleinopathy neurodegenerative disorder in the future. Considering the role of inflammation in the pathogenesis of α-synucleinopathy and a common shared HLA allelic genes in RBD and Sjogren's syndrome, it is suggested that a physiological process which is related to neuroinflammation may be involved in the pathogenesis of RBD.