Síndrome de activación de macrófagos y artritis juvenil de inicio sistémico

Title: Macrophage activation syndrome and juvenile rheumatoid arthritis Macrophage activation syndrome is an abnormal activation of the histiocytic system, which reflects an inappropriate response of the immune system. It can be primary or reactive; in secondary cases, it is mainly associated with autoimmune disorders, most frequently with systemic onset juvenile rheumatoid arthritis (SOJRA). The etiology is still unknown, but several infectious agents have been implicated. It is defined as an acute clinical state of severe hepatic failure, disseminated intravascular coagulation and encephalopathy, associated with the variable presence in bone marrow of activated macrophages with signs of hemophagocytosis. Early diagnosis and treatment improve prognosis of this potentially lethal disorder.