Sjogren's syndrome with and without neurological involvement.

OBJECTIVE: Neurological manifestations of Sjogren's syndrome can be severe but also treatment-responsive. We aimed to systematically evaluate neurological manifestations of primary Sjogren's syndrome and find clinical features allowing sufficient identification of affected patients (pSSN) among those with Sjogren's syndrome without neurological involvement (pSS). METHODS: Para-/clinical features of patients with primary Sjogren's syndrome (2016 ACR/EULAR classification criteria) were compared between pSSN and pSS. At our university-based center, patients with suggestive neurological symptoms undergo screening for Sjogren's syndrome, and newly diagnosed pSS patients are thoroughly evaluated for neurologic involvement. pSSN disease activity was rated by the Neurological Involvement of Sjogren's Syndrome Disease Activity Score (NISSDAI). RESULTS: 512 patients treated for pSS/pSSN at our site between 04/2018 and 07/2022 were included (238 pSSN patients [46%] vs. 274 pSS patients [54%], cross-sectional design). Independent predictors of neurological involvement in Sjogren's syndrome were male sex [p < 0.001], older age at disease onset [p < 0.0001], hospitalization at first presentation [p < 0.001], lower IgG levels [p = 0.04] and higher eosinophil values (treatment-naive) [p = 0.02]. Univariate regression additionally showed older age at diagnosis [p < 0.001], lower prevalence of rheumatoid factor [p = 0.001], SSA(Ro)/SSB(La) antibodies [p = 0.03; p < 0.001], higher white blood cell count [p = 0.02] and CK levels [p = 0.02] (treatment-naive) in pSSN. INTERPRETATION: Patients with pSSN had different clinical characteristics than patients with pSS and represented a large proportion of the cohort. Our data suggest that neurological involvement in Sjogren's syndrome has been underestimated. Intensified screening for neurologic involvement should be included in the diagnostic algorithm for Sjogren's syndrome, especially in males of older age and with severe disease course requiring hospitalization.