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Abstract: SA-PO222

Partial Fanconi Syndrome following Ifosfamide

Session Information

Category: Onconephrology

  • 1700 Onconephrology

Authors

  • Sosa, Piera A., Vanderbilt University Medical Center, Nashville, Tennessee, United States
  • Winer, Aaron, Vanderbilt University Medical Center, Nashville, Tennessee, United States
  • Hinojosa, Sebastian, Vanderbilt University Medical Center, Nashville, Tennessee, United States
  • Hung, Adriana, Vanderbilt University Medical Center, Nashville, Tennessee, United States
Introduction

Partial or complete Fanconi syndrome is a rare yet known complication of ifosfamide administration. Fanconi syndrome characteristically results in metabolic derangements including metabolic acidosis, hypokalemia, hypophosphatemia, and proteinuria. Although Ifosfamide can lead to Fanconi syndrome, not all patients develop this complication. Therefore, pharmacogenomics, the study of how a person’s genetic makeup affects their response to medications and drugs, should be considered when evaluating this disease process

Case Description

A male in his 70’s with recently diagnosed dedifferentiated retroperitoneal liposarcoma presented to the ED 6 days after completing a first cycle of ifosfamide-based chemotherapy. His chief complaint was nausea, vomiting, and weakness. Labs on presentation were notable for hypokalemia, hypophosphatemia, and metabolic acidosis. Given his immunocompromised status, a thorough infectious work-up was obtained and he was found to have bacteremia secondary to chemotherapy port infection. Over the next several days, he continued to have profound electrolyte derangements requiring substantial repletion that were initially attributed to refeeding syndrome. However, further investigation into his significant electrolyte wasting revealed a urinalysis with newly developed proteinuria and phosphaturia, without glycosuria, and a transtubular potassium gradient (TTKG) of 8. Based on his clinical presentation and lab findings, along with his recent chemotherapy initiation with ifosfamide, the patient was ultimately diagnosed with partial Fanconi syndrome. Electrolyte repletion requirement slowly improved throughout admission, demonstrating evidence of renal tubular recovery. He was sent home with daily oral electrolyte supplementation with close outpatient monitoring.

Discussion

Close electrolyte monitoring in patients undergoing chemotherapy treatment with ifosfamide is imperative to avoid missing Fanconi syndrome diagnosis and its detrimental complications. Notably, not all patients undergoing treatment with ifosfamide develop nephrotoxicity leading to Fanconi syndrome. Understanding the role of pharmacogenomics, such as variations in genes encoding CYP3A4 and CYP2B6, is an important area of further investigation to minimize adverse effects from ifosfamide.