Epstein–Barr virus-associated hemophagocytic lymphohistiocytosis in a small child

Hemophagocytic lymphohistiocytosis (HLH) is a rare, potentially lethal disorder, characterized by a dysregulation of the immune response, leading to a severe inflammatory syndrome. Epstein–Barr virus (EBV)-associated HLH is a form of secondary HLH, a fulminant presentation of an otherwise benign viral infection. Patient concerns: We report the case of a 3-year-old girl who presented with fever, signs of accute upper respiratory tract infection and spontaneous, disseminated ecchymoses. Initial laboratory tests revealed pancytopenia. A bone marrow aspirate was performed, which revealed megaloblasts and numerous macrophages, with abundant foamy cytoplasm. Megaloblastic anemia was excluded, as the levels of vitamin B12 and folic acid were both within normal ranges. Diagnosis. Hyperferritinemia, hypertriglyceridemia, hypofibrinogenemia, and splenomegaly were relevant criteria for the diagnosis of HLH, in accordance with the bone marrow specimen. Positive immunoglobulin M antibodies for EBV were supportive of an acute EBV infection, which was the most probable trigger of HLH. The patient's evolution was complicated by a massive epistaxis, in the context of thrombocytopenia which required plasma, thrombocyte, and erythrocyte substitutes. Intervention. The patient was started on a treatment regimen of 8 weeks with etoposide and dexamethasone. Outcome: Her evolution was favorable, the treatment being successful in remission induction. Conclusion: Our case emphasizes the diagnostic challenges of HLH, in a patient with EBV infection whose evolution was hindered by a severe epistaxis, with potentially fatal outcome.