Background The limited application of Ultrasound(US) and MRI to date in SLE is revealing a higher percentage of erosive disease than previous estimates1. Such erosive arthropathy in lupus when associated with rheumatoid factor (RF) or anti-CCP antibody (ACPA) is often referred to as ‘rhupus’ to indicate a mixture of the character of rheumatoid disease (RA)3.
Objectives To evaluate SLE hand symptoms from both an Ultrasound and an MRI perspective.
Methods 50 SLE patients with joint symptoms and 40 RA patients had a detailed US scan (Grey-scale (GSSH) and Power Doppler (PD)) of their hand as per standardised protocols3-4. 32 of the SLE patients also had a contrast enhanced MRI of their hand.
Results Imaging findings related to inflammatory arthritis were detected in 38 (76%) lupus patients. 18 (36.2%) SLE patients had erosive disease at either the wrist or MCP joints on US, an additional 4 patients had erosions on MRI at the wrist which were not visualised on US. One patient had an erosion at the 2nd MCP joint on US which was not seen on MRI. On the basis of the combined US/MRI results the SLE patients were divided into erosive, non-erosive arthritis and arthralgia. There was no difference in median (IQR) CRP between the RA group (5.6 (2.1, 22) mg/dl and the erosive lupus group (4.2 (1.5,7.0)), but there was a significant difference between the RA group and the non-erosive lupus group (1.6 (1.1,4.7))(p = 0.004). CRP also correlated with total erosion score in the lupus group (p = 0.03). There was a higher mean total ultrasound activity score (sum of GSSH and PD) in the erosive lupus group as compared to the non-erosive group (p = 0.03). Five erosive SLE patients had a positive ACPA or RF. A higher percentage of patients in the erosive lupus group (41.6%) had positive anti-Ro antibodies as compared to the non-erosive lupus (28.5%) groups (P <0.001).
Conclusions This is the first study to combine US and MRI in the assessment of SLE patients and to provide information on a cohort of symptomatic lupus arthritis patients where the most significant finding is that 44% had erosive disease, only half ( 22.3%) of which were ACPA or RF positive. Within this sub-group of erosive lupus arthritis patients the most obvious discriminating features were a higher ultrasound activity score, a higher CRP and a higher prevalence of anti-Ro antibodies. This association with CRP and lupus arthritis has been previously described albeit in very small studies5. Advanced imaging techniques may have an impact on the perception of SLE arthritis that will ultimately influence treatment. The ability to assign SLE patients into categories of which the natural history of joint disease progression were known and to target those patients who warrant aggressive treatment would be invaluable in terms of therapeutic rationale.
Wright S et al. Hand arthritis in SLE: an ultrasound pictorial essay. Lupus 2006;15(8)
Fernandez A, et al. Lupus arthropathy: a case series opatients with rhupus. Clinical Rheum 2006 25(2)
Szkudlarek M et al Interobserver agreement in ultrasonography of the finger and toe joints in rheumatoid arthritis. A & R 2003;48(4)
Wakefield RJ et al. Musculoskeletal ultrasound including definitions for ultrasonographic pathology. J Rheum 2005;32(12)
Spronk PE et al. Patients with SLE and Jaccoud’s arthropathy: a clinical subset with an increased CRP response? ARD 1992;51(3)
Disclosure of Interest None Declared