The clinical spectrum and treatment options of macrophage activation syndrome in the pediatric age

Macrophage activation syndrome is a rare and potentially fatal complication of many childhood pathological settings, most frequently reported in systemic onset-juvenile idiopathic arthritis. The disruption of the macrophage-lymphocyte interaction leads to uncontrolled proliferation of highly activated macrophages and T lymphocytes. The syndrome comprises a heterogeneous group of disorders featuring sepsis-like characteristics typically combined with impaired function of natural killer cells and cytotoxic T-cells, haemophagocytosis and hypercytokinemia, often resulting in fatal multiple organ failure. The clinical picture shows high grade fever, hepatosplenomegaly, pancytopenia, lymphoadenopathy, central nervous system involvement and consumptive coagulopathy. Macrophage activation syndrome is associated with high mortality: even though diagnostic criteria have been proposed, definite diagnosis can be a challenge for clinicians, especially in early phases. There is no standardized therapeutic protocol for macrophage activation syndrome, but it is widely recognized that aggressive treatment strategies might strongly influence prognosis. First line-therapy is usually represented by parenteral administration of high dose-corticosteroids, whilst cyclosporine is added in the steroid-resistant cases. In this paper we provide clinical clues and summarize the most recent studies about pathophysiology and management suggestions for macrophage activation syndrome.