The spectrum of conditions mimicking polymyalgia rheumatica in Northwestern Spain

To examine the spectrum and the main clinical data of patients presenting with polymyalgia symptoms who have conditions other than polymyalgia rheumatica (PMR) or PMR associated with giant cell arteritis (GCA) during a 10 year period in Northwestern Spain.

Clinical records of patients presenting with polymyalgia symptoms diagnosed at the Hospital Xeral-Calde Lugo from 1987 to 1996 were reviewed by rheumatology staff members. Patients were considered as having a condition suggestive of PMR if they met the following criteria: (1) Age > or =50 years at the onset of symptoms; (2) severe bilateral pain associated with morning stiffness for > 1 mo in at least 2 of 3 areas: neck, shoulder, and/or pelvic girdle; (3) erythrocyte sedimentation rate at the time of diagnosis > or =40 mm/h. Patients with pure PMR or with PMR associated with GCA were excluded from study.

Twenty-three of the 208 patients (age 67.8 +/- 9.0 yrs) presenting with PMR symptoms were finally diagnosed as having conditions different from PMR and GCA. Men outnumbered women (61%). Malignancies and rheumatic diseases, especially seronegative symmetrical polyarthritis (SSP), were the most common entities. Elderly patients with solid malignancies had a poor response to low doses of prednisone. In patients with hematologic malignancies atypical symptoms of PMR such as lack of accentuation of symptoms with movement and a more diffuse continuous aching were observed. During followup 5 patients developed episodes of SSP (median duration 13 months, range 5 to 24), particularly in both hands, satisfying the American College of Rheumatology 1987 criteria for rheumatoid arthritis. However, arthritis responded promptly to corticosteroids with no disease progression. No cortical erosions or new episodes of PMR were seen in these patients after a followup of 6.8 +/- 2.6 years. With the exception of these 5 patients, duration of polymyalgia symptoms was not longer than 3 months from the onset of polymyalgia symptoms until a specific diagnosis was made.

Polymyalgia symptoms are not uncommon as presenting manifestations of a wide spectrum of conditions. Special concern about the presence of diseases different from PMR or GCA must be considered in patients presenting with atypical symptoms of PMR. Also, the possibility of developing a SSP has to be considered during the followup of these patients.