18th January 2024

Other systemic rheumatic diseases 

These disorders include Sjogren’s syndrome, dermatomyositis, and mixed connective tissue disease. They are characterised by presence of other systemic features (e.g. rashes, dry mouth and dry eyes, myositis, or nephritis) and autoantibodies not usually seen in RA.

In SLE, Jaccoud’s arthropathy (the joint deformities are not caused by joint destruction but by loosening and lengthening of periarticular structures and tendons may be confused with the characteristic joint deformities seen in RA. However, they can be differentiated by physical examination as the deformities are passively ‘correctable’ and on radiology as X-rays show no bony erosions. In addition, ESR and CRP are less well-correlated in other diseases than in RA. Whilst both are raised in RA, CRP is often normal or only minimally elevated in patients with active SLE, even when ESR is elevated.

Image Source: Wikimedia Commons (2021). Jaccoud arthropathy hand x-ray front, Licensed under a creative commons licence. Available for free at: https://commons.wikimedia.org/wiki/File:Jaccoud_arthropathy_hand_x-ray_front.jpg (Accessed: 24 November 2021).