Background As well as other systemic inflammatory diseases with joint compromise, there is an interest to identify the presence of synovitis in systemic lupus erythematosus (SLE) patients, in every follow up consultation. In SLE, the research about subclinical synovitis (that, which is clinically unnoticed but demonstrable by means of image studies) is quiet limited. The majority of studies focused on the use of ultrasound (US) assessment of patients with SLE included non selected patients so many of them counted with patients with chronic synovitis or even deformities. Due to that their results are difficult to compare and the real prevalence of subclinical synovitis is still unknown.
Objectives To determine the prevalence of synovitis in a selected cohort of patients without clinical evidence of arthritis or synovitis.
Methods We performed a prospective study on 96 SLE patients grouped as follows: Group 0 (20) without no historical or present joint symptoms, Group 1 (34) with intermittent joint pain and Group 2 (42) with intermittent arthritis without deformities or erosions. A systematic US study of the carpal, 2nd and 3rd MCP joint of the non dominant hand were performed to all patients. US findings were expressed according to the nomenclature EULAR recommendations for synovitis, power Doppler signal and composite synovitis index.
Results Six patients from group 0 showed any grade of synovitis (30%), 13 from group I (38.2%) and 18 from group II (42.8%). From the whole group of subjects, those with at least a synovitis finding was 37 (38.5%).
Into the 2nd MCP joint, 4 patients (20%) from group 0 showed any grade of synovitis, one of them (5%) with power Doppler (PD) signal. The composite index of synovitis and PD signal (CSI) was 0.3 DE 0.36. In group 1, 9 patients (26.5%) showed any grade of synovitis, 4 of them also showed PD signal (11.8%). The CSI for this group was 0.44 DE 0.48. In group 2, 15 patients (14.3%) showed any grade of synovitis and 6 of them also showed PD signal (14.3%). The CSI for this group was 0.59 DE 0.55. Globally, we detected synovitis in 28/96 patients (29.2%) and PD signal in 11 (11.5%).
Into the 3rd MCP joint, 5 patients (25%) from group 0 showed any grade of synovitis, one of them (5%) also had PD signal. The CSI for this group was 0.3 DE 0.36. In group 1, 8 patients had synovitis (23.5%), 3 of them also showed PD signal (8.8%). The CSI for this group was 0.38 De 0.46. In group 2, 15 patients showed any kind of synovitis (35.7%), 4 of them with PD signal (9.5%). CSI index for this group was 0.57 DE 0.61. Globally there where 27/96 patients with synovitis (28.1%) and 8 with PD signal.
Into the carpal dorsal aspect, 5 patients of group 0 has synovitis (25%) and 3 PD signal (15%). CSI was 0.5 DE 0.54. In group 1, 12 patients had synovitis (35.3%) and 5 PD signal (14.7%) CSI was 0.58 DE 0.54 In group 2, 16 patients has synovitis (38.1%) and 8 PD signal. CSI was 0.61 DE 0.51. Globally, 33/96 has synovitis (34.4%) and 16 PD signal (16.7%).
Conclusions As far as our knowledge goes, this is the first US prevalence study in SLE patients where all deforming and erosive arthritis have been excluded. We have demonstrated that approximately one third of patients without joint symptoms had any grade of synovitis detectable by ultrasonography. The prognosis meaning of our findings will require further prospective initiatives.
Disclosure of Interest None declared