Synovitis in polymyalgia rheumatica.

Synovitis was observed in 13 out of 88 consecutive patients with polymyalgia rheumatica. It is described in detail in five patients, on the basis of clinical radiological observations, joint aspiration, arthroscopy and biopsy. The synovitis of polymyalgia rheumatica cannot be distinguished histologically or at arthroscopy from the appearance seen in mild rheumatoid arthritis. Clinically, however, the synovitis of polymyalgia rheumatica is mild, transient and confined to one or two joints or tendon sheaths. It is not followed by joint deformity or by radiological erosive changes in the bone ends. It may occur at any stage of the disease but particularly at its onset, or when the dose of corticosteroid treatment is reduced.