Abstract: FR-PO270
Lysozyme Toxicity Causing Proximal Tubulopathy in Patient with Acute Monocytic Leukemia
Session Information
- Onconephrology: From AKI to CKD and Everything in Between
November 03, 2023 | Location: Exhibit Hall, Pennsylvania Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Onconephrology
- 1700 Onconephrology
Authors
- Sehmbey, Gurbir S., University of Utah Health, Salt Lake City, Utah, United States
- Abraham, Josephine, University of Utah Health, Salt Lake City, Utah, United States
Introduction
Acute leukemia is a common malignancy that is often associated with acute kidney injury. While rare, lysozyme-induced nephropathy can occur in patients with monocytic leukemia. This condition is caused by overproduction of lysozyme, which is released into blood circulation, filtered by the glomerulus, and reabsorbed by the proximal tubule. The resulting tubular injury can lead to renal insufficiency and electrolyte imbalances.
Case Description
22 years old male was admitted to the hospital with fever. Upon admission, labs revealed marked leukocytosis, white blood cell count of 114.94 k/uL. Bone marrow biopsy confirmed a diagnosis of acute monoblastic/monocytic leukemia. The patient was noted to have acute kidney injury with serum creatinine of 1.48 mg/dL. Urine microscopy was with numerous granular casts and few eumorphic red blood cells. Kidney ultrasound showed normal-sized kidneys, increased parenchymal echogenicity and no hydronephrosis. After rapid resolution of AKI to a baseline creatinine of 0.6mg/dL patient was noted to have hypokalemia with serum potassium of 3.2 mmol/L, hypophosphatemia with phosphorus of 1.4 mg/dL ( normal range 2.2-4.5mg/dL) and uric acid levels of 1.3 mg/dL ( normal range of 3.5-8.5mg/dL). Given the high percentage of blasts and monocytes, lysozyme-induced nephropathy with Fanconi syndrome was considered. Fractional excretion of potassium was > 10%, indicating increased renal loss of potassium. Additional testing revealed elevated serum lysozyme levels (>10.00 ug/mL; normal range 0 – 2.75 ug/mL), supporting a diagnosis of lysozyme-induced nephropathy. Patient was started on aggressive fluid hydration; electrolytes were replaced. The patient was eventually started chemotherapy with normalization of white blood cell count and renal function.
Discussion
Lysozyme-induced nephropathy is a rare complication of acute or chronic monocytic neoplasms associated with overproduction of lysozyme resulting in elevated serum and urine levels. Lysozyme is freely filtered by the glomerulus and reabsorbed in the proximal tubule. Lysozyme can be toxic to proximal tubule cells leading to acute tubular injury, renal insufficiency, hypokalemia due to renal potassium wasting and Fanconi syndrome. Kidney biopsy can be helpful to establish a diagnosis. Recognition of this rare etiology for AKI is important and may guide management of acute and chronic leukemias.