Evidence for synovitis in active polymyalgia rheumatica: sonographic study in a large series of patients

Objective. To determine the frequency and localization of synovitis and enthesitis in patients with active, untreated polymyalgia rheumatica (PMR) by ultrasonography (US). Methods. Polyarticular sonographic evaluation was carried out in 50 consecutive patients with PMR at disease onset. Results were compared with 50 consecutive patients with seronegative spondyloarthropathies (SpA) and 50 with seronegative and seropositive rheumatoid arthritis (RA) at disease onset. Results. Synovitis and/or effusion was detected, in at least one joint, in 100% of patients with PMR. The most frequent alterations observed in patients with PMR were effusion in the subacromial-subdeltoid (SA-SD) bursa in 70% of patients, tenosynovitis of the long head of the biceps tendon (LHBT) in 68%, glenohumeral joint effusion in 66%, tenosynovitis of the flexor tendons in the carpal tunnel in 38%, radiocarpal effusion in 18%, wrist extensors tenosynovitis in 18%, coxofemoral joint effusion in 40%, knee effusion in 38%, and ankle effusion in 10%. Enthesitis and tendonitis of the anchoring tendons were relatively rare in all the articular sites. Comparison of the SpA and PMR patients showed that enthesitis (mostly in the elbow, knee, and heel) was significantly more frequent in SpA. There was a significant difference in glenohumeral and coxofemoral effusion between the PMR and SpA patients (66% vs 16% and 40% vs 14%, respectively). Comparison of PMR and RA patients showed no significant difference in the involvement of entheses, shoulder, hip, or wrist flexor tendons in the carpal tunnel. Synovitis of the elbow, knee, and wrist was significantly more frequent in the SpA and RA patients than in those with PMR. Conclusion. Synovitis was detected in at least one site in 100% of patients with PMR. SA-SD bursitis, LHBT tenosynovitis, carpal tunnel syndrome, and glenohumeral, knee and hip synovitis were the most frequent alterations in PMR. Enthesitis was relatively rare at any articular site.