Epstein-Barr virus induced haemophagocytic lymphohistiocytosis.

Haemophagocytic lymphohistiocytosis (HLH) is a rare condition of uncontrolled immune activation as a result of an inherited genetic defect or in response to malignancy, autoimmune disease, rheumatological disease, AIDS infection or post-transplant immunosuppression. Described here is the case of a 19-year-old Caucasian man who presented with complaints of worsening fever, new-onset jaundice and lethargy after failing treatment for suspected infectious mononucleosis. Physical examination was significant for fever and splenomegaly while laboratory results revealed transaminitis, cytopaenia, indirect hyperbilirubinaemia and elevated ferritin, raising the likelihood of both autoimmune haemolytic anaemia and HLH. He tested positive for Epstein-Barr virus (EBV), and bone marrow biopsy revealed hypercellular marrow with haemophagocytosis and no evidence of malignancy. High dose steroids were initiated with significant improvement in haemoglobin, resulting in a final diagnosis of HLH secondary to acute EBV infection. The patient was discharged on continued high-dose prednisone with planned taper and consideration of outpatient rituximab therapy for 4 weeks. High clinical suspicion and prompt evaluation were critical to early treatment and decreased morbidity.