Myalgias and Myopathies: Polymyalgia Rheumatica and Giant Cell Arteritis.

Polymyalgia rheumatica (PMR) and giant cell arteritis (GCA) are related inflammatory disorders that often coexist. Both are most common among women, whites, and older individuals. PMR is characterized by morning stiffness, pain, and decreased range of motion in the shoulders, neck, and pelvis. Diagnosing PMR can be challenging because no standard set of criteria or single diagnostic test exists. Patients with PMR benefit rapidly from treatment with oral glucocorticoids, and full recovery is likely, although adverse effects of treatment contribute to morbidity. GCA is a subacute vasculitis in which focal, segmental inflammatory infiltrates primarily affect cranial arteries. Diagnosis of GCA is based on clinical features, such as headache, jaw pain, vision changes, and temporal artery tenderness, along with an elevated erythrocyte sedimentation rate and inflammation seen on temporal artery biopsy. Permanent vision loss can occur, so patients who may have temporal arteritis should be started on glucocorticoids promptly. If treatment for GCA is started before visual symptoms progress, the prognosis for a full recovery is good. In PMR and GCA, relapses or exacerbations necessitating changes in therapy occur in up to 60% of patients.