[Macrophage activation syndrome in Chinese children with systemic onset juvenile idiopathic arthritis]

To review and analyze the clinical features, treatment, and outcome of macrophage activation syndrome (MAS) in children with systemic onset juvennil rheumatoid arthritis (SOJRA).

Retrospective review and analysis were performed on cases with MAS from a prospectively collected database of children with SOJRA from the year of 2003 to 2006 in the Hospital.

Twenty four patients (21 boys, 3 girls) were diagnosed as having MAS with SOJRA. Mean age of the patients with MAS at diagnosis was 7 years, and the duration prior to diagnosis of MAS was 12 months. No trigger factors were found except in one case whose MAS was triggered by use of methotrexate and in another by parvovirus B19 infection. High grade fever, new onset hepatosplenomegaly and lymphadenopathy, pancytopenia, liver dysfunction were common clinical features in all the 24 cases (100%). Bleeding from skin, mucous membrane and gastrointestinal tract were noted in 9 cases (38%). Twelve (50%) cases had CNS dysfunction (high intracranial pressure, seizure and coma). Six cases (25%) developed ARDS. One patient suffered from renal damage. The laboratory test revealed elevated live enzymes and ferritin, decreased value of ESR, albumin, complete blood count and fibrinogen in all the 24 cases. Bone marrow examination supported the diagnosis of definite hemophagocytosis in the 24 cases. Lymph node biopsy was done for one case and histopathological examination showed that the node was full of activated macrophage. As to treatment, five cases only received high dose steroids (three of them died), 14 cases were treated with high dose steroids plus cyclosporine (one died), two were treated with steroids plus cyclosporine and etoposide (none died). The causes of deaths were ARDS and CNS involvement. In three of the cases who died, treatment was given up by their parents.

MAS is a rare and potentially fatal complication of SOJRA. Most of our patients were male. Bone marrow studies support the diagnosis. CNS involvement and ARDS were poor prognostic signs. Early diagnosis and aggressive therapy are essential.