A case of chronic myelomonocytic related lysozyme-induced nephropathy

Abstract

Background Lysozyme-induced nephropathy (LyN) is a rare cause of acute kidney injury (AKI) in patients with chronic myelomonocytic leukemia (CMML). Diagnosing LyN is challenging due to the numerous potential and concurrent aetiologies. Previous case reports have demonstrated the diagnostic utility of serum and urinary lysozyme measurements, which may correlate with renal dysfunction; however, the role of renal imaging remains unclear and renal biopsy remains essential for diagnosis.Case presentation An independent 80-year-old male presented to an Australian tertiary hospital with stage 3 AKI on a background of CMML previously treated with thioguanine and hydroxycarbamide. Renal tract ultrasound revealed expansile, non-vascular material bilaterally in renal collecting systems which was confirmed by renal biopsy to be lysozyme-induced nephropathy causing renal dysfunction. Despite escalated anti-leukaemic treatment he progressed to stage 4 chronic kidney disease contributing to increasing frailty and eventually pursued voluntary assisted dying after a fall with terminal traumatic injuries.Conclusions LyN is a rare cause of acute kidney injury amongst patients with chronic myelomonocytic leukaemia. This case highlights a rare instance of LyN and illustrates potential radiological markers that may aid in diagnosis. It also emphasizes the complexity of managing LyN in the context of underlying haematological malignancies.