Evaluation for Clinical Predictors of Positive Temporal Artery Biopsy in Giant Cell Arteritis

Abstract

Conclusions: A positive temporal artery biopsy specimen is more likely if patients present with weight loss or pain with mastication. Corticosteroid therapy before temporal artery biopsy does not affect positivity of a temporal artery biopsy specimen. Summary: In patients aged >50 years, temporal arteritis (TA) is the most common systemic vasculitis. Tenderness of the scalp or new onset of headache are common complaints. Ocular manifestations of TA include decreased vision, diplopia, and amaurosis fugax, and up to 20% of patients may develop irreversible visual loss from optic nerve ischemia. Pain with mastication is present in 50% of patients (Salbarani C, et al; Lancet 2008;372:234). However, many patients present with predominately constitutional symptoms such as weight loss, fatigue, or fever. Inflammatory markers, such as erythrocyte sedimentation rate and C-reactive protein, are frequently elevated in patients with TA, but they are not specific. Diagnosis of TA can therefore be difficult. An abnormal finding on a temporal artery biopsy specimen is a part of the American College of Rheumatology criteria for diagnosis of TA (Hunder GG, et al; Arthritis Rheum 1990;33:112); however, up to two-thirds of temporal artery biopsy specimens are negative. It would therefore be useful to determine if there are clinical parameters that most likely correlate with TA to identify patients who will most likely benefit from treatment while waiting to undergo a temporal artery biopsy (Youngee BR; Mayo Clin Proc 2004;79:483). In this study, the authors examined clinical parameters associated with a positive temporal artery biopsy specimen in patients with symptoms suggestive of TA. This was a retrospective study of 82 consecutive patients who underwent temporal artery biopsies by a single surgeon at a single institution. Medical records were reviewed for clinical symptoms, laboratory findings, final diagnosis, and biopsy results. The microscopic examination suggested evidence of arteritis in 22 patients (26.8%). In two patients, TA was clinically diagnosed with a negative temporal artery biopsy specimen. Patients presenting with weight loss or pain with mastication were most likely to have a positive temporal artery biopsy specimen (odds ratio, 4.5 [95% CI, 1.45-13.93] and odds ratio, 3.71 [95% CI, 1.28-10.76]). Laboratory findings did not predict a positive temporal artery biopsy specimen. Use of steroids before the temporal artery biopsy was not associated with a decreased likelihood of a positive specimen. Comment: High doses of corticosteroids are the initial treatment of TA. These drugs are clearly not benign in the elderly patient. For logistical and referral reasons, a temporal artery biopsy specimen may not be available as rapidly as desirable. If one does not wish to treat all patients suspected of TA before biopsy results, the study provides some guidance for determining patients who are at the highest risk of actually having a positive biopsy specimen. Pain with mastication and weight loss appear to be more important parameters in predicting a positive temporal artery biopsy specimen than laboratory markers of inflammation. It is also useful to know that prednisone therapy will not decrease the likelihood of a positive temporal artery biopsy specimen, at least if the biopsy occurs relatively soon after the beginning of steroid therapy.