To perform an observational retrospective cross-sectional case-control study to evaluate prevalence, clinical patterns and outcomes of CNS involvement in a large cohort of primary SS (pSS) patients.
A total of 424 pSS patients, diagnosed according to the 2002 criteria proposed by the American-European Consensus Group, were checked for CNS involvement after exclusion of secondary causes. Demographic, clinical, seroimmunological data were compared between patients with and without CNS involvement. Neuroimaging data were also analysed.
CNS involvement was detected in 25 (5.8%) patients (24 females and 1 male) both at disease onset (52%) and later (48%) with a mean latency after diagnosis of 7 years. Diffuse (40%), focal/multifocal (36%), multiple sclerosis (MS)-like disease (20%) and isolated optic neuritis (4%) were the most common CNS clinical pictures. Disease duration, lung involvement and decreased C(4) were associated with CNS involvement, while articular manifestations were more frequently observed in patients without neurological complications. Most cases had an acute, often recurrent course with spontaneous remission or only mild neurological impairment.
CNS involvement represents a rare but not negligible complication of pSS, which may occur with a bimodal temporal pattern, both at onset and later, prompting attention in the differential diagnosis of apparently isolated neurological syndromes. Lung involvement emerged as the strongest risk factor for CNS involvement with a relative risk of 7.9, along with disease duration and decreased C(4).