Acute phase reactants in the initial phase of giant cell arteritis.

The erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), fibrinogen and haptoglobin were followed weekly during the initial phase of corticosteroid treatment in 18 patients with 19 episodes of giant cell arteritis (GCA). Fibrinogen and CRP decreased most rapidly, with normal values in 67% of the patients after two weeks of treatment. After two weeks 56% of the patients had normal ESR values and 76% after five weeks. Haptoglobin normalised most slowly, no patient having a normal value after one week, 29% after two weeks and 75% after six weeks. For routine clinical use, we found the ESR alone sufficient for monitoring the initial steroid treatment.