Background and aims PRES in SLE is increasingly recognised. This study aimed at determining the prevalence, clinical features, brain imaging findings, risk factors, and outcomes of PRES in Thai SLE patients.

Methods SLE patients with PRES seen between 1 January 1986 and 31 August 2013 were identified. Controls were matched with hospital number and disease duration to cases (ratio, 1:4). Clinical features, brain imaging patterns, risk factors, treatment and outcome of PRES were determined.

Results Of 1141 SLE patients, 26 PRES episodes occurred 20 in females (prevalence 1.8%). Mean±SD age at diagnosis and disease duration was 29.3±13.1 and 2.8±3.4 years, respectively. Among the 26 episodes, 24 (92.3%) had seizure, 14 (53.8%) headache, 9 (34.6%) fever and vomiting and 8 (30.8%) visual disturbance. All of them had acutely elevated blood pressure. 20 and 23 patients had active lupus nephritis (LN) within 3 months prior to and at PRES onset, respectively. Dominant parietal-occipital pattern was the most common brain imaging abnormality. 22 episodes improved with blood pressure control. Immunosuppressive therapy was given for active disease in 8 episodes. Anti-convulsive therapy could be discontinued in 21 of 22 episodes (median duration 3 months). Auto-immune hemolytic anaemia (AIHA) and LN were PRES risk factors (OR 6.55, 95% CI 1.09–39.39, p=0.04 and OR 3.06, 95% CI 1.12–8.39, p=0.03, respectively). 6 patients (23.1%) died during PRES episodes. The mortality rate in SLE patients with PRES was significantly higher than those without (30% vs. 10%, p<0.001).

Conclusions The mortality rate was high in Thai SLE with PRES. AIHA and LN were risk factors for PRES.