Primary Sjögren's syndrome: central and peripheral nervous system involvements.

Primary Sjögren's syndrome (pSS) is a common systemic autoimmune disease characterised by exocrinopathy resulting in dryness of the mouth and eyes, unexplained fatigue and diffuse pain. Neurological involvement is uncommon in pSS, involving the central nervous system in 2-5% of cases and more frequently the peripheral nervous system in 5-15% of cases. The diagnosis of pSS is to be considered when confronted with symptoms such as mouth and eye dryness, fatigue and pain, the most frequent of pSS symptoms. Objective measures of oral and eye dryness may help assert the diagnosis of pSS, as well as ACR/EULAR criteria. Differential diagnoses have to be excluded in patients exhibiting neurological symptoms, such as cryoglobulinaemic vasculitis or multiple sclerosis, before considering a neurological involvement specific to pSS. The treatment of these neurological manifestations takes into account different parameters, such as the presence of cryoglobulinaemic vasculitis, the severity of the symptoms, a rapidly progressing evolution and the failure of previous symptomatic treatments.