Look for distended, beaded retinal veins with temporal arteritis. Temporal arteritis may be part of an immune-mediated process, although the cyclical nature of outbreaks in a study in Minnesota suggests a possible infectious etiology. ESR serves as a useful guide to disease activity. Almost one half of patients with temporal arteritis test abnormal for liver function. Chest radiograph may be a useful screening test for a thoracic aneurysm.
Definitive diagnosis relies on a temporal artery biopsy.
Biopsy does not need to be performed urgently. As infection tends to be patchy or segmental, multiple biopsies may be required. Perform bilateral biopsies if initial biopsy proves negative and clinical suspicion remains high. Steroid therapy may affect results of biopsy, but inflammatory changes usually persist for 2-4 weeks after initiation of treatment. Crucial to correct ED care of patient with temporal arteritis is maintaining a high index of suspicion and a low threshold to treat.