Epstein-Barr Virus Infection Complicated by a Splenic Infarct in a Patient With Methylenetetrahydrofolate Reductase (MTHFR) Mutation.

Splenic infarction has been reported as a rare complication of infectious mononucleosis (IM), documented in only a few case reports. We present the case of a patient diagnosed with IM complicated by splenic infarction, with thrombophilia workup revealing a homozygous methylenetetrahydrofolate reductase (MTHFR) mutation and elevated homocysteine levels. Infections play a critical role in thrombosis formation through various mechanisms, primarily inflammation due to cytokine production, which alters the coagulation cascade and promotes platelet activation. Elevated homocysteine is considered a weak prothrombotic factor, with its effect amplified by the presence of other risk factors. The prothrombotic effects of homocysteine are poorly understood and are thought to involve proinflammatory effects, oxidative stress, and platelet adhesion. This case adds to the growing body of literature associating Epstein-Barr virus (EBV) infection with splenic infarction. Timely diagnosis and management with anticoagulation therapy can help prevent complications associated with splenic infarction.