Does early treatment of macrophage activation syndrome prevent fatal outcome in patients with severe systemic juvenile idiopathic arthritis?

Macrophage activation syndrome (MAS), a rare complication of various diseases, mainly systemic inflammatory connective tissue disorders, is being increasingly recognized. Most frequently MAS occurs in systemic juvenile idiopathic arthritis (sJIA), yet description of typical clinical features is challenging. Prognosis of the syndrome is often poor therefore prompt diagnosis and appropriate medical treatment are critical for survival. We report the case of MAS diagnosed in a 7-year-old boy with severe generalized sJIA presenting description of our dilemmas associated with the diagnosis. We identified the condition as MAS on the basis of criteria defined by Ravelli et al. To make diagnosis of MAS was difficult, especially because some clinical symptoms are characteristic both for MAS and sJIA. Owing to deterioration of a general condition of the patient we took the risk of including treatment with cyclosporine. This treatment significantly improved the condition of the child and in our opinion prevented a fatal outcome