Utility of Erythrocyte Sedimentation Rate and C-Reactive Protein for the Diagnosis of Giant Cell Arteritis

Abstract

Objectives 1) To evaluate the utility of erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) for the diagnosis of giant cell arteritis (GCA) 2) to determine the frequency of normal ESR and CRP at diagnosis of GCA. Methods All patients undergoing temporal artery biopsy (TAB) between 2000 and 2008 were identified. Only subjects with both ESR and CRP at the time of TAB were included. The medical records of all patients were reviewed. Results We included 764 patients (65% women), mean age 72.7 (±9.27) years, who underwent TAB. Biopsy was consistent with GCA in 177 patients (23%). Elevated CRP and elevated ESR provided a sensitivity of 86.9% and 84.1% respectively, for a positive TAB. The odds ratio (OR) of a concordantly elevated ESR and CRP for positive TAB was 3.06 (95% CI 2.03, 4.62) while the OR for concordantly normal ESR and CRP was 0.49 (95% CI 0.29, 0.83). Seven patients (4%) with a positive TAB for GCA had a normal ESR and CRP at diagnosis. Compared to GCA patients with elevated markers of inflammation, a greater proportion of these patients had polymyalgia rheumatica symptoms (p=0.008) while constitutional symptoms, anemia and thrombocytosis were observed less often (p<0.05). Conclusions CRP is a more sensitive marker than ESR for a positive TAB that is diagnostic of GCA. There may be clinical utility in obtaining both tests in the evaluation of patients with suspected GCA. A small proportion of patients with GCA may have normal inflammatory markers at diagnosis.

Clinical correlation of biopsy results in patients with temporal arteritis

“…Mahr et al 15 reported a 15% histological evidence of TA in 1,520 patients. Kermani et al 16 also found 22% accuracy for pathological diagnosis in 1,106 patients. However, Suelves et al 17 presented 68.4% positive biopsy results in their study.…”

Response to Grzybowski and Justynska

“…In both 'poppers maculopathy' and photic maculopathy, there is focal disruption of the IS-OS junction centred at the fovea. [1][2][3][4] Moreover, the size, shape, echogenicity, and temporal evolution of the SD-OCT lesions appear indistinguishable in the two conditions. Patients also present with the same symptoms (scotoma, reduced vision, and phosphenes) and have the same slit-lamp findings (a pale yellow foveal lesion).…”

“…Unfortunately some papers referred to were not published at the time of writing. 3,4 The table provided by Dr Grzybowski and Justynska highlights some important articles, some of which were referenced in our original report 5 and others which were summarized by key articles referenced. 6,7,8 Dr Grzybowski and Justynska remark that typical features commonly associated with GCA were not presented in our case.…”

“…Patients also present with the same symptoms (scotoma, reduced vision, and phosphenes) and have the same slit-lamp findings (a pale yellow foveal lesion). [1][2][3][4] Indeed, it appears that in people using poppers, the two conditions can only be reliably distinguished by eliciting a history of excess light exposure and not by clinical features.…”

Response to Banerjee et al

“…However, the authors' inadvertent omission of two recent articles evaluating laboratory predictors of a positive temporal artery biopsy is potentially misleading. 2,3 The study by Parikh et al 4 used a much lower cut-off for normal CRP of 5 mg/l, which may be the reason for the high sensitivity of CRP reported in their study. In the study by Walvick and Walvick, 2 a CRP cut-off of 5 mg/l yielded a sensitivity of 94.9%, which means that 5.1% had a falsely normal CRP (less than 5 mg/l).…”