Temporal Arteritis Revealing Antineutrophil Cytoplasmic Antibody-Associated Vasculitides: Case-Control Study of 50 Cases.

BACKGROUND: Temporal arteritis (TA) is a typical manifestation of giant cell arteritis (GCA). Rarely, ANCA-associated vasculitides (AAV) can be revealed by TA, leading to misdiagnoses of GCA and inappropriate treatments. METHODS: We retrospective included patients with TA revealing AAV (TA-AAV), and compared them with classical GCA patients. RESULTS: Fifty patients with TA-AAV (median age 70 years) were included. Thirty-three (66%) patients presented atypical symptoms for GCA (ENT, renal, pulmonary and neurological involvement in 32%, 26%, 20% and 16%, respectively). ANCA were screened at disease onset in 33 cases, and were positive in 88%, leading to diagnosis of early TA-AAV in 20 cases. AAV diagnosis was delayed in 30 cases after a median interval of 15 months. Compared to GCA, TA-AAV patients were younger (70 vs. 74 years), more frequently men (48 vs. 30%), had high frequency of atypical manifestations and higher CRP levels (10.8 vs. 7.0 mg/dL). Temporal artery biopsy (TAB) from TA-AAV showed fibrinoid necrosis and small branch vasculitis in 23% each, whereas it did not in GCA. Treatment failure-free survival was comparable between early TA-AAV and GCA, whereas those with delayed TA-AAV patients had a significant higher risk of treatment failure compared to GCA [HR 3.85 (1.97-7.51), P<0.0001)]. CONCLUSION: TA revealing AAV should be considered in case of atypical manifestations for GCA, GCs refractoriness or early relapse. Analysis of TAB for small branch vasculitis and/or fibrinoid necrosis could be useful. Detection of ANCA should be performed in case of suspected GCA with atypical clinical features and/or TAB.status: Published onlin