The macrophage activation syndrome (MAS) is an uncommon complication of chronic rheumatic diseases, specially systemic onset juvenile idiopathic arthritis (JIA). It can be triggered by infectious (viral or bacterial) or malignant diseases, non-steroidal anti-inflammatory or disease modified anti-rheumatic drugs, changes in the therapy and rheumatic diseases. The clinical features present at the onset are related mainly with central nervous system involvement, hepatic and renal failure and pancytopenia. We describe the clinical, evolutive features and treatment of three patients with JIA that developed MAS.
macrophage activation syndrome; juvenile idiopathic arthritis; hemophagocytosis; children; cyclosporine