Juvenile Idiopathic Arthritis Complicated by Macrophage Activation Syndrome: A Case Report

Juvenile Idiopathic Arthritis (JIA) is an autoimmune disorder affecting children under 16, causing joint inflammation, fever, rash, and iridocyclitis. In some cases, JIA can lead to Macrophage Activation Syndrome (MAS), a secondary hemophagocytic lymphohistiocytosis often triggered by systemic juvenile idiopathic arthritis (s-JIA). An 18-year-old male with a past medical history of JIA presented with persistent high-grade fever, abdominal distension, and systemic symptoms non-responsive to antibiotics. MAS was confirmed after bone marrow aspiration and high-dose intravenous methylprednisolone were used. The report emphasizes the importance of early recognition and treatment of MAS to prevent severe complications and improve outcomes in patients with JIA. This case report details the diagnostic process, including specific disease activity scoring, imaging findings, and key immunological markers, to strengthen the clinical presentation. It emphasizes the importance of early recognition and treatment of MAS to prevent severe complications and improve outcomes in patients with JIA, aligning with current registry data and systematic reviews on MAS in JIA.

Ectopic pregnancy, transvaginal ultrasound, creatine phosphokinase, diagnostic accuracy.