Prolonged Fever and Intravenous Immunoglobulin Resistance in Kawasaki Disease: Should Macrophage Activation Syndrome Be Considered?

Introduction: Macrophage activation syndrome (MAS) is a rare and potentially fatal complication of Kawasaki disease (KD). Typically, MAS presents as the exacerbation of KD, manifested by prolonged fever and resistance to treatment. Early and accurate diagnosis might be challenging due to overlapping features of MAS and intravenous immunoglobin (IVIG)-resistant KD and lack of validated diagnostic criteria. Case Presentation: In this article, we report four cases of KD with prolonged fever that were eventually diagnosed and treated as MAS. Three cases were boys and one infant was a girl. The mean age of the cases was 29 months. Three cases had typical and one case had atypical KD. Two cases had abnormal findings in echocardiography and three cases had hepatomegaly. In laboratory evaluation, all of them had thrombocytopenia, increased liver enzymes, and hyperferritinemia. All the patients were treated with intravenous high-dose methylprednisolone (pulse therapy) after IVIG therapy, two cases with oral cyclosporine, and one case with infliximab. There was no mortality in our cases, and in long-term follow-up, all the patients had normal clinical, laboratory, and echocardiography findings. Conclusions: KD resistant to IVIG and sustained fever have high diagnostic values in MAS with underlying KD.