Temporal Arteritis (TA) is commonly associated with the sudden onset of a unilateral headache centered around the temporal region. The most devastating consequence of TA is blindness though this is only reported in up to 50% of cases though can be bilateral in up to 33% of patients.
According to the American College of Rheumatology criteria for classification of temporal arteritis this diagnosis can be made in the ED without a biopsy. You just need at least 3 of the following 5 items to be present (sensitivity 93.5%, specificity 91.2%) to make the diagnosis :
Age of onset older than 50 years
New-onset headache or localized head pain
Temporal artery tenderness to palpation or reduced pulsation
Erythrocyte sedimentation rate (ESR) greater than 50 mm/h
Abnormal arterial biopsy (necrotizing vasculitis with granulomatous proliferation and infiltration)
References
Hunder GG, Bloch DA, Michel BA, et al. The American College of Rheumatology 1990 criteria for the classification of giant cell arteritis. Arthritis Rheum. Aug 1990;33(8):1122-8
