Background/Purpose: Giant cell arteritis (GCA) is a non-necrotizing granulomatous arteritis involving large vessels, whereas antineutrophil cytoplasmic antibodies (ANCA)-associated vasculitides (AAV) are a group of necrotizing vasculitis involvement small and medium-size vessels. AAV can be revealed by temporal arteritis (TA) leading to cephalic symptoms and misdiagnosis of GCA, whereas therapeutic management and prognosis strongly differ between these two entities.

Methods: We conducted a retrospective multicenter study including patients with symptomatology of TA revealing AAV. We compared these cases (TA-AAV) to controls with GCA randomly selected with a ratio of 1:2.

Results:

Fifty patients (26 women, mean age 70 years) were included. Initial symptoms of TA were: cephalic symptoms suggesting GCA in 44 (88%) cases, polymyalgia rheumatica symptoms and cough in 15 (30%) each, and ocular manifestations in 8 (16%). All patients without cephalic symptoms had inflammation on TAB consistent with GCA. However, 33 (66%) patients presented at initial presentation atypical symptoms for GCA: ENT involvement in 16 (32%), renal involvement (haematuria, proteinuria or acute renal faillure) in 13 (26%), pulmonary involvement (nodule, alveolar condensation or alveolar hemorrhage) in 9 (18%), peripheral neuropathy in 8 (16%), abdominal pain and cutaneous manifestations in 5 (10%) each, episcleritis in 3 and cardiac involvement in 2. ANCA were screened at initial presentation in 33 cases, and were found in 88%, targeting MPO in 62% and PR3 in 38%.

Overall, diagnosis of AAV was made after a median time of 15.2 months (range 1.1-201), after initial flare in 20 (40%), after refractory disease in 13 (26%) and after vasculitis relapse in 17 (34%). AAV diagnoses were GPA, PAM and EGPA in 31, 16 and 3 cases, respectively. Manifestations leading to AAV diagnoses by physicians were common, including pachymeningitis in 4 cases. Once AAV diagnosis was made, all patients received glucocorticoids, in combination with immunosuppressive agents in 84% (cyclophosphamide, rituximab, azathioprine or methotrexate). After median follow-up of 43.2 months, 14 patients presented a relapse of the AAV and 5 patients died.

To identify AAV in patients with TA manifestations, we compared TA-AAV with GCA patients. AAV patients were slightly younger than GCA (70 vs. 74 years, P=0.01), and had more frequently: peripheral neuropathy (16 vs. 0%, P<0.001), lung involvement (40 vs. 16%, P=0.002), ENT (34 vs. 0%, P<0.001) and renal involvement (37 vs 0%, P<0.001). Histologically, TAB from AAV had significantly more fibrinoid necrosis (23 vs. 0%, P<0.001) and adventitial vasculitis (23 vs. 0%, P<0.001) and less frequently granulomatous inflammation (13 vs. 40%, P=0.01), disruption of the internal elastic membrane (45 vs. 69%, P=0.04) and giant cells (29 vs. 60%, P=0.01)).

Conclusion: Diagnosis of AAV should be considered in patients presenting with cephalic symptoms, especially in case of unusual manifestations and in case of necrosis or adventitial vasculitis on TAB. ANCA testing should also be performed in all patients with TA manifestations before retaining GCA diagnosis.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/temporal-arteritis-revealing-antineutrophil-cytoplasmic-antibody-associated-vasculitides-a-retrospective-study-of-50-cases/