Characteristics and outcome of intractable vasculitis syndrome in children: Nation-wide survey in Japan.

Objective: Primary systemic vasculitis (PSV) is a rare disorder in children and difficult to distinguish from other diseases. However, appropriate diagnosis and prompt treatment will affect on the morbidity and mortality of intractable PSV. In this study, we conducted a nationwide survey in Japan, to clarify epidemiology and clinical outcome of PSV.Methods: We had sent survey questionnaires to most of the Japanese institutions that employed pediatricians, requesting the number of patients with refractory PSV who were diagnosed and treated between 2007 and 2011. Respondents were asked to provide detailed information on the clinical and laboratory features of each case they had managed. Those with Kawasaki disease or Henoch-Shonlein purpura vasculitis (IgA vasculitis) were excluded.Results: Of all the institutions surveyed, 1123 (37.3%) patients responded, finally, total of 49 patients with intractable PSV, defined by those with resistant to treatment and steroid-dependent, or with any complication associated with prognosis, were selected. The diagnosis was Takayasu arteritis in 31, polyarteritis nodosa in 11, granulomatosis with polyangitis in 2, microscopic polyangitis in 1, and ANCA negative microscopic polyangitis in 1. In those with Takayasu arteritis, 67% were treated with an immunosuppressive agent, 22% with biological modifiers, and 16% with surgical procedures. In other types of disease, 88% of the patients were treated with an immunosuppressive agent, and 12% with biological modifiers. Two with Takayasu arteritis died being terminally ill.Conclusion: This nationwide survey establishes the heterogeneous characteristics of PSV in children. Although questionnaire-based, the results of our analysis should be useful in planning prospective studies to identify the most effective therapy for each subtype of multifaceted disease.