[Late onset spondyloarthropathy misdiagnosed as polymyalgia rheumatica]

Polymyalgia rheumatica (PMR) is a frequent cause for long-term corticosteroid therapy. Management of PMR is difficult and recommendations (regarding diagnosis and treatment) from the British Society of Rheumatology have been recently published in order to avoid false diagnosis and unnecessary corticosteroid therapy. On the other hand, late onset spondyloarthropathies are difficult to diagnose due to their various presentation (peripheral and axial manifestations, usually associated with severe systemic manifestations) and the absence of validated diagnosis criteria in the elderly.

We report on eight patients, who all of them initially responding to Bird's criteria for PMR, and whose outcome was refractory PMR with multiple flares, poor therapeutic response, with inability to taper steroids.

After a mean follow-up of 25 months, a diagnosis of late onset spondyloarthropathy was done in all theses patients based on clinical history, physical examination, and spine MRI. In four of the cases the use of TNFα blockers allowed to taper corticosteroid and to control the disease. Retrospectively, the diagnosis at presentation was difficult.

Among PMR patients with poor response to corticosteroids and multiple flares, the possibility of a late onset spondyloarthropathy should be discussed. There is an unmet need for validated diagnosis criteria in such patients.