Influenza b associated hemophagocytic lymphohistiocytosis complicated by influenza-associated pulmonary aspergillosis: a case report

Abstract Background Hemophagocytic lymphohistiocytosis is a severe hyperinflammatory syndrome with high mortality due to immune overactivation. Invasive pulmonary aspergillosis, once mainly seen in immunocompromised individuals, is increasingly identified in critically ill patients without traditional risk factors, especially in the context of severe viral pneumonia such as influenza. Case presentation A 21-year-old male presented to the emergency department with fever, myalgia, nausea, dysphagia, and diarrhea, subsequently developing acute hypoxemic respiratory failure. Initial evaluation revealed hepatosplenomegaly, marked hyperferritinemia, hypertriglyceridemia and elevated inflammatory markers. Influenza B infection was confirmed by nasopharyngeal RT-PCR, and secondary hemophagocytic lymphohistiocytosis was diagnosed. During hospitalization, invasive pulmonary aspergillosis was diagnosed by transbronchial biopsy, leading initiation of targeted treatment. Conclusion This case highlights the significance of influenza as a rare trigger of hemophagocytic lymphohistiocytosis in immunocompetent patients and underscores the risk of secondary invasive pulmonary aspergillosis during immunosuppressive therapy. It emphasizes the urgent need for clear management guidelines to address the challenges of simultaneous hyperinflammation and opportunistic fungal infection.