Polymyalgia rheumatica and giant cell arteritis.

The original descriptions of polymyalgia rheumatica (PMR) and giant cell arteritis (GCA) in the medical literature date back to 1888 and 1890, respectively. Classification criteria for PMR and GCA are not standardized since most authors used subjective criteria based on their personal experience. Only one study has evaluated criteria for PMR and has found seven variables with high discriminant value. Criteria for GCA are less varied because a positive biopsy of the temporal artery is diagnostic. However, combinations of different clinical and laboratory features have been used for diagnosis when biopsy is negative or missing. Assessment of PMR/GCA is based on the serial determination of markers of acute phase such as ESR, CRP, or plasma viscosity. However, their value in predicting recurrence of the diseases is poor. New immunological factors including soluble interleukin-2 receptors, interleukin-6, serum soluble CD8, and serum soluble intercellular adhesion molecule-1 are presently under investigation.