Elderly patients are more likely to be affected by temporal arteritis (TA), an inflammatory vasculitis. Patients with TA tend to present in a variety of ways, with ocular and systemic symptoms. Lee and Brazis developed a guide for the evaluation of patients with TA based on a search of the literature from 1966 to 1998. The authors developed the following criteria for evaluation of patients: (1) clinical suspicion, (2) laboratory testing and (3) temporal artery biopsy.
Clinical suspicion can be based, in part, on the American College of Rheumatology study that determined highly sensitive parameters for diagnosis of TA. These parameters include age more than 50 years, a Westergren erythrocyte sedimentation rate (ESR) of more than 50 mm per hour and an abnormal temporal artery biopsy. The highest specific clinical features include jaw or tongue claudication, visual abnormalities and temporal artery abnormalities (e.g., decreased pulse, tenderness or nodules). High clinical suspicion includes any one of these three criteria in a patient more than 50 years of age with an elevated ESR, or if three or more of the following four criteria are met: (1) new localized headache, (2) temporal artery abnormality, (3) elevated ESR (more than 50 mm per hour) and (4) abnormal temporal artery biopsy (e.g., necrotizing arteritis or multinucleated giant cells).
Vision loss is an important finding. About one fifth of patients with TA and vision loss have no systemic symptoms of TA. Conversely, about one quarter of patients with TA continue to have visual acuities of 20/40 or better. Vision loss in patients with TA usually is the result of anterior ischemic optic neuropathy. TA should be suspected in patients more than 50 years of age who have a diagnosis of anterior ischemic optic neuropathy. Steroid therapy should be initiated (even in the absence of an elevated ESR). A unilateral temporal artery biopsy should be performed, and treatment should be initiated if the biopsy is positive for TA. If the biopsy is negative but suspicion remains high, a con-tralateral biopsy should be considered. Patients with medium clinical suspicion for TA should undergo an ESR and a temporal artery biopsy. Medium clinical suspicion is classified as meeting any one of the highest specificity criteria or having anterior ischemic optic neuropathy. In addition, any two of the following represents medium clinical suspicion: elevated ESR, new headache in an older patient or a clinical temporal artery abnormality. If both temporal artery biopsies are negative, alternative reasons for an elevated ESR should be sought (e.g., infectious disease, malignancy, diabetes mellitus, connective tissue disease). A normal ESR and a negative unilateral biopsy make the diagnosis of TA less likely. However, up to 30 percent of patients have a normal ESR with biopsy-proven TA; thus, other features should be sought. It should also be remembered that an ESR of 40 mm per hour (or 30 mm per hour, according to some) should not be considered abnormal in patients more than 65 years of age. C-reactive protein, an acute-phase reactant, is also considered a marker for TA.
Treatment of patients with TA is critical to avoid vision loss, and therapy should be initiated based on clinical suspicion, not biopsy results. The initial prednisone dosage should be between 60 to 100 mg per day. Premature or rapid decrease of the prednisone dosage may contribute to continued vision loss, but a general rule is that the lowest dosage should be taken for the shortest period of time to adequately control symptoms of TA. One method is to decrease the dosage by 10 percent per week, with an individualized determination based on symptoms, side effects and ESR. Usually, steroid therapy can be discontinued within one year, although some patients need prednisone therapy for years. An every-other-day dosage of prednisone has not been found to be efficacious, although it may be useful once the acute TA is controlled. Little information exists about treating TA in patients who have contraindications to steroid therapy, although methotrexate or immunosuppressive treatments have been proposed. Evaluation of patients with TA is thus based on symptoms, laboratory values, temporal artery biopsy and clinical suspicion. An algorithm based on these features is provided (see the accompanying figure on page 2492).