The objectives of this study were to evaluate the frequency and characteristics of the peripheral musculoskeletal manifestations in polymyalgia rheumatica (PMR), evaluate if PMR with peripheral synovitis represents a subset with a more severe disease, and examine for clinical and laboratory characteristics at onset of PMR that might later predict rheumatoid arthritis (RA).
Patients were diagnosed with PMR according to the 1982 Chuang criteria. Patients were followed up between 1990 and 2002. The following musculoskeletal manifestations at onset and during the follow up were considered: peripheral synovitis, distal extremity swelling with pitting edema, carpal tunnel syndrome, and distal tenosynovitis.
Thirty-eight of the 74 patients (51%) showed distal musculoskeletal symptoms: 29 (39%) had peripheral synovitis, 4 (5%) presented pitting edema, 4 (5%) experienced carpal tunnel syndrome, and one (1.3%) had distal tenosynovitis. These manifestations resolved completely after corticosteroid therapy was initiated. Peripheral synovitis was oligoarticular and often transient. The joints most frequently involved were the wrist, metacarpophalangeal, and knee. Erythrocyte sedimentation rate (ESR) was normal in 7 patients. When comparing patients with PMR with and without peripheral synovitis, no statistically significant differences were found in the studied variables. Through the first year of follow up, 7 patients fulfilled the American College of Rheumatology 1987 criteria for RA, 2 patients developed giant cell arteritis, and 3 had associated malignancy. Patients who developed RA had statistically significantly increased presence of persistent synovitis and a smaller decrease in mean ESR after treatment with corticosteroids.
Fifty-one percent of the patients with PMR presented distal musculoskeletal manifestations, with peripheral synovitis being the most frequent one. Patients with PMR with peripheral synovitis did not represent a high-risk subgroup with more severe disease. Seven patients who developed criteria for seronegative RA within the first year of follow up had presented statistically significant persistent synovitis compared with those who continued as PMR and also showed a smaller initial decrease in mean ESR after steroid treatment was initiated. The absence of persistent arthritis and the benign course of the arthritis permit the distinction of PMR from other inflammatory arthropathies.