AB0643 Are there any distinctive finding in ANCA-associated vasculitis related pulmonary involvement in comparison with Connective Tissue Diseae or Idiopatic pulmonary fibrosis

Abstract

BackgroundPatients with ANCA associated vasculitis (AAV) have a wide spectrum of pulmonary involvement from parenchymal necrotizing granuloma formation, trecheobronchial inflammation, pulmonary capillaritis to interstitial lung disease. Pulmonary involvement is relatively common in connective tissue diseases (CTDs). Both rheumatologic disorders and idiopatic pulmonary fibrosis (IPF) might cause the usual interstitial pneumonia (UIP) pattern. However, little is known regarding the clinical and radiologic similarities/ dissimilarities of those diseases.ObjectivesWe aimed to evaluate the thoracic computed tomography (CT) findings of patients with AAV, CTDs-related interstitial lung disease (ILD) or IPF.MethodsPatients whose thoracic CT performed at the time of the diagnosis or relapse of AAV (n=64), at the time of the diagnosis of CTD related ILD (n=55) or IPF (n=52) were included in the analysis. Demographic, clinical and serological data were collected retrospectively. Radiological patterns of pulmonary involvement were evaluated by two expert pumonary radiologists and abnormal thoracic CT findings were classified according to Fleischner Society guidelines. Intra- and inter-observer variation were calculated. Multoniminal logistic reggresion was performed to identfy disease specific findings in thoracic CT.ResultsA total of 171 patients were included and of them 64 patients (62.5% with granulomatosis with polyangiitis, 37.5% with microscopic polyangiitis) in AAV group, 55 patients in CTD related ILD (50.9% with scleroderma, 40.0% with rheumatoid arthritis, 9.1% other or undifferensiye connective tisue disease) group and 52 patients in IPF group. Demographic and thoracic CT findings were summarized in Table 1. In univariate analysis according to Fleishner Society definition, patients with AAV had more common pulmonary noduls, cavities, consolidation. However, patients with AAV were less likely to have interlobular septal thickening (ILST), lymph node adenopathy (LAP) and reticulation compared to both CTD related ILD and IPF. In addition, among those groups of rheumatic diseases, cavities and alveolar hemorrhage were detected only AAV. In multinominal logistic reggresion, the presence of nodul and consolidation and the absence of ILST and mediastinal LAP were independent determinant findings in thoracic CT in patients with AAV in comparison with both CTD related ILD or IPF.Table 1.Demoraphic characteristics and Thoracic CT findings of patientsAAV patients (n=64)CTD related ILD (n=55)IPF (n=52)pCharacteristicsAge at diagnosis, yrs, mean (SD)58.6 (15.0)61.8 (12.0)72.4 (9.4)&lt;0.001Sex, male, %70.330.975&lt;0.001Smoking, ever, %77.826.562.80.29Chest CT findings according to Fleishner guideline, %Ground glass opasity29.738.29.60.003Reticulation19.052.794.2&lt;0.001Interlobular septal thickening28.669.198.1&lt;0.001Peribronchial thickening11.120.03.80.03Honeycombing14.325.563.5&lt;0.001Bronchiectasis31.347.386.5&lt;0.001Consolidation45.312.75.8&lt;0.001Micronodules6.33.600.07Nodules45.310.93.8&lt;0.001Cavities23.400&lt;0.001Eymphysema18.87.319.20.96Mosaic attenuation pattern7.82038.5&lt;0.001Alveolar hemorrage17.200&lt;0.001Mediastinal lymph node adenopathy26.753.757.70.002Pleural effusion14.11.800.001Pericardial effusion6.39.100.16ConclusionThe results of this study show that in additon to clinical and labaratory characteristics, some thoracic CT imaging findings like the presence of nodules and consolidation and the abscence of LAP and ILST may be useful to differentiate pulmonary involvement of AAV from other relatively common rheumatologic conditions and IPF. In addition, alveolar hemorrhage and cavities may be particular manifestations of AAV.Disclosure of InterestsNone declared</jats:sec