Síndrome de activación macrofágica en pacientes con artritis idiopática juvenil sistémica: análisis de 17 casos observados en un hospital terciario

introduction. macrophage activation syndrome is a severe complication of certain rheumatic diseases, mainly systemic juvenile idiopathic arthritis (sjia). the objective of this presentation is to describe the clinical and biochemical features of patients with sjia who developed mas, and their response to different therapeutic regimes. population, materials and methods. retrospective, observational analysis of children with a diagnosis of sjia who developed mas between 1993 and 2007. diagnosis of mas was formulated based upon clinical, biochemical and, in some cases, histopathological evidence. results. seventeen children (14 girls) were included. age varied between 1 and 16 years (median 10 years). mas developed during the first year of aijs course in 10 children (it was the presenting manifestation in 6). its main features were: continuous fever (100%), hepatomegaly (100%), splenomegaly (76%), cutaneous rash (59%), lymphadenopathy (53%), hemorrhage (53%), cns involvement (41%), edema (29%); elevated liver enzimes (94%), thrombocytopenia (76%), normal sedimentation rate (76%), hypertriglyceridemia (71%), coagulopathy (65%), leukopenia (59%), hypofibrinogenemia (47%); hemofagocytosis was found in 9 out of 13 (69%) patients who underwent biopsy. high-dose corticosteroids were prescribed in 17 cases and immunosupressants in 6. twelve patients remitted and 5 died due to multiorgan failure. conclusions. mas is a syndrome of variable severity that may cause significant morbimortality. presence of continuous fever, hepatosplenomegaly, coagulopathy, cns involvement, cytopenias and normal sedimentation rate in a child with aijs should prompt diagnosis, even without evidence of hemophagocytosis. immunosuppressive therapy was effective in the majority of the studied patients.