Breakthrough fungal pneumonia in Multiple myeloma post-immunosuppressive therapy with polypharmacy, complications, and outcome in elderly patient

Abstract

Background: Clonal proliferation of plasma cells in the bone marrow is a hallmark of Multiple myeloma (MM), a malignant neoplasm associated with severe immunological dysregulation. While novel agents have improved survival, they have also altered the infectious risk profile, making invasive fungal infections (IFIs) a growing threat in non-neutropenic elderly patients. Case: We describe a 78-year-old female with MM undergoing Lenalidomide maintenance who experienced severe breakthrough pneumonia subsequent to hip surgery. Initially resistant to broad-spectrum antibiotics, her condition was complicated by sepsis, atrial fibrillation, and acute heart failure. Advanced diagnostics revealed a dual infection comprising MRSA and probable invasive fungal disease, indicated by positive serum Galactomannan and Beta-D-Glucan. The patient was effectively treated with Voriconazole, Linezolid, and cardiac optimisation. Conclusion: This case highlights the significant risk posed by mixed infections in elderly immunocompromised patients. It underscores the essential role of early fungal biomarker testing and the management of complex polypharmacy when conventional treatment does not prevent clinical decline.