Abstract
Hemophagocytic lymphohistiocytosis (HLH) is a rare disease more commonly found in neonates and adolescents. It can be classified as primary/genetic or acquired following viral infection, lymphomas, or autoimmune diseases. There is not enough evidence of the prevalence of this disease in adults, but, when diagnosed, it is most commonly secondary to viruses, such as Epstein-Barr virus (EBV). We report an adult case of HLH secondary to EBV in a 27-year-old Hispanic male with no significant past medical history, who presented to the emergency department with constant fatigue, myalgia, nausea, vomiting, right upper quadrant abdominal pain, and dizziness. He met six out of eight potential criteria for HLH, including splenomegaly, fever, cytopenia, hypofibrinogenemia, hyperferritinemia, and positive sCD25. He was diagnosed based on the HLH-2004 diagnostic criteria and was treated with the HLH-94 protocol. After being hospitalized for almost two months, the patient failed to respond to treatment and passed away. Prompt treatment of HLH is advised due to rapid deterioration.