From epidemiology to future perspectives
Polymyalgia rheumatica is a chronic, inflammatory disorder of unknown cause that affects people over age 50 years. Classic symptoms include pain and long-term morning stiffness of the neck, shoulders, hips, upper arms, and thighs. Although markers of inflammation are often raised, no specific laboratory test exists for the disorder and the diagnosis is based on clinical assessment. Provisional classification criteria were published in April, 2012, by a collaborative initiative of the European League Against Rheumatism and the American College of Rheumatology. Several other disorders can mimic polymyalgia rheumatica. In particular, clinical manifestations can be difficult to differentiate from other forms of inflammatory arthritis such as spondyloarthritis and rheumatoid arthritis. Imaging studies such as ultrasonography and MRI typically show a predominantly periarticular inflammatory process. A subset of patients has an associated inflammatory vasculopathy affecting large arteries (giant cell arteritis). The standard treatment is low-dose glucocorticoids, which provide symptomatic relief for most patients. However, disease relapses are common, and treatment with glucocorticoids is associated with substantial morbidity. Improved understanding of disease pathogenesis might allow for more targeted immunotherapy.