DIFFERENTIAL DIAGNOSIS OF SYSTEMIC-ONSET JUVENILE ARTHRITIS AND RHEUMATIC MASKS OF ONCOHEMATOLOGICAL DISEASES: A RETROSPECTIVE COHORT STUDY

Background. Patients with malignant oncohematological diseases (OHD) may have such symptoms as fever, lymphadenopathy, hepatosplenomegaly,  joint pain, arthritis, elevated erythrocyte sedimentation rate (ESR) and C-reactive  protein (CRP) concentration, anemia that require differentiation from clinical implications of systemic juvenile idiopathic arthritis (sJIA).Objective.  Our aim was to determine diagnostic criteria that can differentiate  rheumatic masks of OHD from sJIA.Methods.  The retrospective  study included 86 children with sJIA and 21 children with OHD who had rheumatic masks and were hospitalized in rheumatological departments with an initial diagnosis of sJIA. OHD were represented  by acute lymphoblastic leukemia (n = 17), neuroblastoma (n = 1), and lymphomas (n = 3).Results. Blast cells in the peripheral blood test were detected in 9/17 (53%) patients with acute leukemia at different times from the appearance of complaints and hospitalization. Diagnostic criteria for differentiating OHD from sJIA were the number of active joints  3 (diagnostic odds ratio, OR, 4.4, 95% confidence interval, CI, 1.5–13.2), CRP concentration < 15 mg/L (OR 5.6, 95% CI 1.7–18.4), platelets     307   109/L (OR 22.9, 95% CI 4.9–107.0), white blood cells     8.9   109/L (OR 50.2, 95% CI 6.3–401.3), albumin > 43.3% (OR 28.8, 95% CI 5.6–149.2),  absence of exanthema (OR 39.8, 95% CI 8.4–188.5).  The most frequent symptoms with the greatest specificity were night pain (sensitivity 0.57, specificity 1.0), bone pain (sensitivity 0.95, specificity 1.0), pathological fractures (sensitivity 0.14, specificity 1.0).Conclusion. The identified diagnostic criteria can be used for differential diagnosis of OHD with rheumatic masks and sJIA