Abstract 193: Hemophagocytic lymphohistiocytosis following kawasaki disease:Differential Diagnosis in IVIG Refractory Kawasaki Disease

Abstract

Introduction: Hemophagocytic lymphohistiocytosis(HLH) is a systemic inflammatory disorder characterized by uncontrolled histiocytic proliferation, hemophagocytosis and up-regulation of inflammatory cytokines. Thus, both HLH and Kawasaki disease(KD) are characterized by prolonged fever, and are diagnosed by a clinical and laboratory scoring system, concurrent manifestation of HLH and KD has been described in the literature. We describe two cases of children who diagnosed as KD initially, but after intravenous gamma globulin(IVIG) failed to produce clinical response, were found to have HLH. Case report: A 3-year-old boy who had previous KD history 5 months ago was admitted for 9day fever and skin rash. His symptoms were fulfilled KD criteria, and echocardiography showed dilated right coronary artery of 4.2mm. He was treated with 2 cycles of IVIG until fever subsided. However, 2 days later, he got fever again and cytopenia(Hb<9.0), hypertriglyceridemia, high level of ferritin was shown and had splenomegaly on physical examination. In the suspicion of HLH, bone marrow biopsy was done and revealed hemophagocytosis, consistent with HLH. A second case of 11-month-old boy admitted for 8-day fever with Kawasaki feature. Although, he showed incomplete feature(fever, skin rash, conjunctival injection, cervical lymphadenopathy), echocardiography showed dilated left main coronary artery(3.5mm) and treated with IVIG. However, 2days after IVIG administration, he was still pyrexial. The laboratory findings fulfilled 5 diagnostic criteria of HLH; bicytopenia(anemia, thrombocytopenia), hypofibrinogenemia, hyperferritinemia, hemophagocytosis in bone marrow, raised level of soluble IL-2 receptor. In both cases, the patients treated according to the HLH protocol 2004, and after that clinical symptoms and laboratory findings were improved. Several causes of febrile illness, EBV, CMV, rubella, parvo-viral infection, for example, were excluded. Comment: There is considerable overlap between the clinical syndromes of KD and HLH and early recognition and treatment of these two disease entity is imperative to avoid fatal outcomes in severe cases. Thus, these should both be considered and excluded in any child with unremitting fever and rash.