Diagnosis of giant cell arteritis using clinical, laboratory, and histopathological findings in patients undergoing temporal artery biopsy.

OBJECTIVE: To identify the clinical, laboratory, and histopathological features that may predict the diagnosis of giant cell arteritis (GCA). METHODS: A retrospective chart review was performed on patients who underwent temporal artery biopsy (TAB) between January 1, 2011 and March 31, 2019. Patient demographics, clinical characteristics, laboratory features, histopathological features, and biopsy results were collected. GCA status was determined by a neuro-ophthalmologist (OOA). Stepwise logistic regression analysis was performed to identify features that predict GCA status. RESULTS: Of 101 patients who underwent TAB, 31 (31%) were diagnosed with GCA. Age was found to be statistically significant for the diagnosis of GCA (P = 0.009), with an average age of 74.4 years ( ± 8.1) in those with GCA vs. 68.9 years ( ± 10.0) in those without. The incidence of transient vision loss was higher in GCA than non-GCA patients (P = 0.005). Anterior arteritic ischemic optic neuropathy (n = 3), ophthalmic artery occlusion (n = 2), and posterior ischemic optic neuropathy (n = 1) were seen only in the GCA group. Of the 31 GCA patients, 15 had active GCA (48%), 3 (10%) had healed temporal arteritis (HTA), 8 (26%) had suggested HTA, and 5 (16%) had false negative biopsies. Of the 70 non-GCA patients, 63 (90%) had negative biopsies, 2 (3%) had HTA, and 5 (7%) had suggested HTA. Histopathological analysis revealed that CD68 staining had a sensitivity of 69% and specificity of 86%. Both presence of multinucleated giant cells (MNGC) and transmural inflammation had 100% specificity; however, sensitivity was ≤ 50%. In patients with negative TABs and complete risk factor data available (n = 66), the odds of GCA increased 2.16-fold every 5 years of age, and 1.08-fold every mg/day of oral steroid use. A biopsy result of HTA had an odds ratio of 84.7 and suggested HTA of 49.2 against a negative TAB for diagnosis of GCA. CONCLUSION: Age at time of biopsy, HTA, and suggested HTA are predictive for the diagnosis of GCA. Transient vision loss is more commonly seen in GCA, and anterior arteritic ischemic optic neuropathy, ophthalmic artery occlusion, and posterior ischemic optic neuropathy are important ophthalmic manifestations of GCA. CD68 staining is more sensitive but less specific for diagnosing GCA in comparison to other histopathologic findings such as presence of MNGC and transmural inflammation. Further work is recommended to investigate the importance of the specific histopathologic finding of CD68 staining in the diagnosis of GCA.

A Unique Presentation of Levamisole-Induced Antineutrophil- Cytoplasmic-Antibody-Positive Vasculitis Presenting as Inflammatory Orbitopathy.

A 35-year-old woman with a history of cocaine abuse presented with progressively worsening OS pain. Neuroimaging revealed a 3-cm ill-defined left orbital lesion involving the intraconal and extraconal spaces. The orbital mass was biopsied via an anterior orbitotomy approach. Pathology demonstrated prominent angiocentric granulomatous and lymphoplasmacytic inflammation consistent with vasculitis. Laboratory tests were significant for neutropenia, positive perinuclear antineutrophil cytoplasmic antibodies with high titer, and positive myeloperoxidase antibodies, consistent with levamisole-induced vasculitis. To the authors' knowledge, this is the first reported case of cocaine-levamisole-induced vasculitis presenting as orbitopathy.