POS1344 EVALUATING THE MULTIVISCERAL INVOLVEMENT ON ADULT-ONSET STILL’S DISEASE TO RETRIEVE IMAGING-BASED DIFFERENCES IN PATIENTS WITH AND WITHOUT MACROPHAGE ACTIVATION SYNDROME; RESULTS FROM A SINGLE-CENTRE OBSERVATIONAL STUDY
Authors: I. DI Cola, F. Bruno, O. Berardicurti, R. Monti, A. Conforti, A. DI Sibio, V. Pavlych, F. Sensini, C. Masciocchi, A. Barile, P. Cipriani, P. Ruscitti
Journal: Annals of the Rheumatic Diseases (2021)

Background: Adult-onset Still’s disease (AOSD) is a rare systemic inflammatory disorder usually affecting young adults, burdened by life-threatening complications, mainly macrophage activation syndrome (MAS), a secondary form of hemophagocytic lymphohistiocytosis [1]. In this context, the importance of an accurate assessment of AOSD is suggested to promptly recognise the multivisceral involvement of the disease which is associated with life-threatening complications. The assessment of the most aggressive subsets of the disease could guide the clinicians when to apply additional resources but avoiding unnecessary expenditures in patients with a less severe clinical picture. Objectives: In this study, we aimed at describing the multivisceral involvement of the disease to retrieve imaging-based differences in AOSD patients with and without MAS. Methods: The present evaluation has been designed as a cross-sectional study to descriptively compare the multivisceral involvement in AOSD patients with and without MAS. Patients admitted to our Institution, who underwent a total body CT scan, were selected from our historical cohort and assessed. Clinical and CT scan characteristics of AOSD patients with and without MAS were compared. Clinical and CT scan characteristics of AOSD patients with and without MAS were analysed by parametric or non-parametric t tests for all continuous variables, and chi squared test was used for categorical ones, as appropriate. Furthermore, possible correlations among radiological outcomes with laboratory markers and systemic score were estimated by using a point-biserial coefficient correlation. Results: This study evaluated 39 AOSD patients (men 64.1%), mean age of 48.8±16.6 years). Out of those, 14 patients (35.9%) were complicated by MAS. These patients showed higher values of ferritin [AOSD: 770.0 (1306.5) ng/mL vs MAS: 2926.3 (4918.5) ng/mL p=0.003] and systemic score (AOSD: 4.6±1.4 vs MAS: 6.9±1.7, p&lt;0.0001). AOSD patients with MAS presented a higher prevalence of lung disease than others (AOSD: 56.0% vs MAS 85.7% p=0.048). Lung disease correlated with the systemic score (coefficient 0.491, p=0.003). AOSD patients with MAS were more frequently characterised by hepatomegaly (AOSD: 12.0% vs MAS: 50.0% p=0.019) and splenomegaly (AOSD: 16.0% vs MAS 50.0% p=0.033), respectively, than others. Hepatomegaly correlated with CRP (coefficient 0.421, p=0.016), ferritin (coefficient 0.397, p=0.020), and systemic score (coefficient 0.391, p=0.022). Furthermore, the presence of splenomegaly correlated with the systemic score (coefficient 0.439, p=0.009). CT scan features of abdominal effusions were more frequently observed in AOSD patients with MAS than those without this complication (AOSD: 12.0% vs 57.1% p=0.007). Finally, a higher percentage of AOSD patients with MAS showed a significant lymph node enlargement, either mediastinal or abdominal, than others on CT scan (AOSD: 36.0% vs MAS 71.4% p=0.048). The presence of lymphadenomegaly correlated with the systemic score (coefficient 0.368, p=0.032). Conclusion: Our findings showed a higher prevalence of multiorgan involvement in AOSD patients with MAS, suggesting imaging-based differences, although other studies are needed to fully assess this issue. Pulmonary disease, hepatomegaly, splenomegaly, lymph nodes enlargement, and abdominal effusions were associated with these more aggressive patients. References: [1]Giacomelli R, Ruscitti P, Shoenfeld Y. A comprehensive review on adult onset Still’s disease. J Autoimmun. 2018 Sep;93:24-36. Disclosure of Interests: None declared