THU0301 SPLENIC INVOLVEMENT IS NOT RARE IN ANCA-ASSOCIATED VASCULITIS HOWEVER SPLENIC INFARCT MIGHT ONLY BE ASSOCIATED WITH GRANULOMATOSIS WITH POLYANGIITIS

Abstract

Background Anti-neutrophil cytoplasmic antibody (ANCA) associated vasculitis (AAV) is a systemic necrotizing vasculitis of small and medium-sized arteries. Although, upper and lower respiratory tracts and kidneys are predominantly affected; other organs/systems can also be involved in the course of the disease and in some cases, it might be difficult to differentiate subgroups based on the clinical presentation. Splenic involvement has been rarely reported, mainly in patients with granulomatosis with polyangiitis (GPA), in fact, it was thought to be underestimated, as it is often asymptomatic. Objectives In this study, we aimed to investigate systematically the frequency of splenic infarct and related factors in our AAV patients. We also evaluated the role of splenic involvement in the differentiation of AAV subgroups. Methods Patients with a diagnosis of AAV in whom abdomen/thorax computed tomography (CT) was performed were included in the study. An experienced radiologist examined CT images for the presence of splenic involvement. The clinical and demographic data were retrospectively collected. Results In total 70 (30 [43%] female and mean age 56.1 ± 15.7 years) AAV patients (38 [54%] had granulomatosis with polyangiitis (GPA); 20 [29%] microscopic polyangiitis; 11 [16%] renal-limited disease and 1 [1%] eosinophilic granulomatosis with polyangiitis) were included in the analysis. Splenic pathologies including splenomegaly, hypodense lesion/s, lobulation, and infarction were seen in 21 (30%) patients with AAV. Splenic infarct was observed in seven (10%) patients and all had GPA with renal involvement and PR3ANCA positive. Three of them had total splenic infarct or auto-splenectomy. None of these patients had a history of endocarditis, shock or malignancy before CT. Splenic infarction was found to be negatively correlated with age at diagnosis (p=0.017; rho=-0.285), and positively associated with ENT (ear-nose-throat) (p= 0.002; rho=0,370) and eye involvements (p=0.013; rho=0,324). Conclusion Our results show that splenic pathologies might not be rare in AAV however, infarction can help to separate GPA from other AAVs. In young GPA patients, in particular, those with ENT and eye involvement, physicians should remember splenic infarction. Since almost half of our cases had severe infarction or autosplenectomy, clinicians might consider immunization in GPA patients for vaccine-preventable infections.