Giant cell temporal arteritis with a normal erythrocyte sedimentation rate: report of a case.

Giant cell temporal arteritis (GCA) is a systemic vasculitis that affects individuals older than 50. Erythrocyte sedimentation rate (ESR) has typically been used in the ED as a screening test to rule out GCA. There have been documented cases in medicine and rheumatology journals of biopsy-proven giant cell arteritis with a normal or low ESR before steroid therapy. In the ED, the practitioner must use multiple resources to make the diagnosis of GCA, as there is no specific test that establishes the diagnosis. Delaying this diagnosis based on a laboratory value can create substantial morbidity and mortality for the patient. We report a case of an elderly woman who developed visual changes and had a delayed diagnosis because of a normal ESR value.