A Rare Fatal Case of Hemophagocytic Lymphohistiocytosis With Central Pontine Myelinolysis in the Setting of Epstein-Barr Virus Reactivation.

Hemophagocytic lymphohistiocytosis (HLH) is a rare hyperinflammatory disorder associated with infections, malignancies, autoimmune conditions, and inflammatory states. HLH is characterized by unregulated cytokine release and immune activation, leading to widespread tissue damage. In this case, we describe a male in his 30s who presented to the emergency department with concerns about sepsis after being diagnosed with mastoiditis a week earlier. Further investigation revealed persistent fevers, pancytopenia, hepatosplenomegaly, hyperferritinemia, and hypertriglyceridemia, fulfilling the diagnostic criteria for HLH. Additional serologic testing revealed a significantly elevated Epstein-Barr virus (EBV) viral load on PCR, with positive immunoglobulin G (IgG) and negative IgM, consistent with EBV reactivation. HLH in the setting of EBV reactivation is rare and may be associated with a poor prognosis. Central pontine myelinolysis is a commonly fatal neurologic condition that is rarely attributed to HLH but should be considered when other causes are ruled out such as electrolyte derangements and rapid correction.