A Rare Case of Mononucleosis-Induced Splenic Infarction in a Patient With Sickle Cell Trait.

Splenic infarction is a rare complication of Epstein-Barr virus (EBV) mononucleosis, particularly in patients with underlying hematologic conditions. We present a rare case of EBV-associated splenic infarction in a 20-year-old male with sickle cell trait (SCT), highlighting the potential overlap between SCT and infection-related ischemic complications. The patient presented to the emergency department with one week of left upper quadrant pain, fever, night sweats, dyspnea, and concentrated urine following suspected dehydration after outdoor activity. Initial Monospot testing was negative. CT imaging revealed multiple splenic infarcts, and the patient was admitted with presumed splenic infarction secondary to an acute sickling crisis. His clinical course improved with supportive care, and he was discharged the following day. Peripheral blood smear obtained after discharge revealed atypical lymphocytes, and follow-up serologic testing two weeks later confirmed markedly elevated EBV viral capsid antigen IgM, supporting the diagnosis of infectious mononucleosis-associated splenic infarction. The patient was counseled on contact precautions and activity restrictions, with complete symptom resolution. Although the initial presentation suggested SCT-related vaso-occlusion, EBV was ultimately identified as the likely trigger. This case highlights the limitations of early Monospot testing and the importance of considering EBV infection in young patients with splenic infarction, even when SCT offers an alternative explanation. Additionally, it raises the possibility of overlap between SCT and infection-related ischemic complications.