Background Incidence and prevalence of CNS involvement in SLE is highly variable in all published series. Minor and non-specific symptoms such as headaches, mild cognitive dysfunction or depression, collectively labeled neuropsychiatric lupus, are clouding the true incidence of specific CNS events.

Objectives To evaluate the incidence and prevalence of definite and severe CNS involvement in SLE patients.

Methods From a cohort of 1093 SLE patients, fulfilling the 1997 ACR criteria, 458 were prospectively evaluated in our department (July 2008 to June 2011). 370 of them had no previous history of CNS involvement attributed to SLE and were finally enrolled in the study. Major and objective CNS manifestations were codified according to ACR definitions excluding minor CNS events such as headaches, mild depression or unspecified cognitive impairment. European Consensus Lupus Activity Measurement score (ECLAM) and Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) SELENA Modification, were used to evaluate disease activity. The SLICC/ACR Damage Index was used to assess accumulated damage due to the disease. We used the Chi-Square test for categorical and the Mann-Whitney test for quantitative variables to evaluate differences between subgroups of patients with CNS involvement. Binary logistic regression models were used to assess differences between patients with and without CNS involvement.

Results After excluding the non-specific and minor CNS events, only 16/370 (4.3%) patients remained with a total of 19 definite CNS events. These included seizures (42.1%), strokes (31.6%), myelopathy (21%), optic neuritis (5.3%) and acute psychosis (5.3%). Incidence was evaluated among newly diagnosed SLE patients and was 7.8/100 person years. Among hospitalizations for SLE, 13.7% were due to CNS involvement. Epileptic seizures were associated with high disease activity scores and early onset during the disease course, while myelopathy correlated with lower disease activity scores and NMO-IgG antibodies (P≤0.05). Stroke incidence correlated with APS coexistence (P=0.06). When these patients were compared with the 354 SLE patients without neurologic manifestations, CNS involvement correlated with high ECLAM and SLEDAI scores (P<0.001).

Conclusions Clinically severe CNS involvement is rare in SLE patients, accounting for 7.8/100 person years. CNS involvement correlates with disease activity and coexistence of specific autoantibodies (NMO) that define the respective CNS syndromes.

Disclosure of Interest None Declared