Neurological involvement in primary Sjögren’s syndrome: a retrospective analysis of clinical, radiological, laboratory and therapeutic correlations

Background Neurological complications are increasingly recognised in Sjögren’s Syndrome, yet their prevalence and determinants remain incompletely characterised. This study aimed to evaluate the frequency, patterns and clinical associations of neurological involvement in patients with primary Sjögren’s syndrome (pSS). Methods A retrospective analysis was performed on 49 patients diagnosed with pSS according to 2016 ACR/EULAR criteria. Clinical, laboratory, neuroimaging and electrophysiological data were reviewed. Neurological involvement was defined using attribution-based criteria. Statistical analyses included multivariable logistic regression, with Bonferroni correction for multiple comparisons. Results Neurological complications were present in 65.3% (32/49) of patients. Among these, 21 (65.6%) had isolated peripheral nervous system (PNS) involvement, 4 (12.5%) isolated central nervous system (CNS) involvement and 7 (21.9%) combined PNS–CNS involvement. The most frequent manifestations were headache attributed to pSS (61.2% of the total cohort) and peripheral neuropathy (44.9%). Among the 22 patients who underwent brain MRI, white matter lesions were observed in 45.5%, and 9.1% showed multiple sclerosis-like lesions. Electrophysiological studies (n=23) revealed sensory neuropathy in 26.1% and motor neuropathy in 13.0%. No bivariate associations remained significant after Bonferroni correction. However, multivariable regression identified higher EULAR Sjögren’s Syndrome Disease Activity Index scores (OR 1.21, p=0.03), positive antithyroid antibodies (OR 4.8, p=0.04) and joint pain (OR 5.2, p=0.02) as independent predictors of neurological involvement. Disease was controlled in 91.8% of cases, with 6.1% showing persistent activity and 2.0% mortality. Conclusion Neurological complications are common in pSS and associated with higher systemic disease activity. Peripheral neuropathy and pSS-attributed headache predominate, while MRI often reveals non-specific white matter changes. Multivariable analysis, but not univariate testing, identified key correlates of neurological involvement, underscoring the importance of comprehensive disease assessment. Prospective studies with standardised neurological phenotyping are needed.