Macrophage activation syndrome in Kawasaki Disease: More common than we thought?

MAS may be a frequently under-recognized complication of KD, because the understanding of complications and diagnostic criteria are still in progress. The HLH 2009 criteria have low sensitivity and specificity for the diagnosis of MAS complicating KD. When hepatosplenomegaly is present in KD patients with abnormal laboratory findings, such as cytopenia, liver dysfunction, hyperferritinemia, elevated serum LDH, hypofibrinogenemia, and hypertriglyceridemia, the presence of MAS should be considered.