Hypocomplementemia Associated with Macrophage Activation Syndrome in Systemic Juvenile Idiopathic Arthritis and Adult Onset Still’s Disease: 3 Cases: Table 1.

Abstract

To the Editor: Macrophage activation syndrome (MAS) is a life-threatening complication seen in association with childhood inflammatory diseases, most commonly in systemic juvenile idiopathic arthritis (sJIA)1,2,3. MAS has also been described in the setting of adult-onset Still’s disease (AOSD), systemic lupus erythematosus, drug reactions, and viral infections4,5. Decrease in C3 has been documented in patients with lupus and MAS4; however, to our knowledge, hypocomplementemia has not been previously described as associated with MAS in sJIA or AOSD. We describe 2 patients with sJIA, and a third with AOSD, who developed MAS with hypocomplementemia during the acute phase of illness. Patient 1, a 9-year-old boy, presented with high quotidian fever, evanescent rash, and arthritis. He had leukocytosis (24 × 109/l) with elevated markers of inflammation: erythrocyte sedimentation rate (ESR) 52 mm/h and C-reactive protein (CRP) 17.3 mg/dl. Liver enzymes and renal function were normal. Ferritin was 5623 ng/ml. Serologic tests for Epstein-Barr virus, parvovirus, cytomegalovirus, Lyme disease, mycoplasma, and group A streptococcus were negative. Complement levels, obtained by the primary intensive care team, showed slightly increased C3 (166 mg/dl) and normal C4 (32 mg/dl). He was discharged with a diagnosis of new-onset sJIA and prescribed indomethacin. Several days later, he returned to clinic with worsening symptoms and petechial … Address correspondence to Dr. Gorelik; E-mail: mark.gorelik{at}chp.edu