Kidney Week

Abstract: TH-PO0415

Acquired Bartter-Like Syndrome Following Polymyxin Therapy in an Elderly Patient: A Case Report

Session Information

• Fluid, Electrolyte, and Acid-Base Disorders: Clinical - 1
  November 06, 2025 | Location: Exhibit Hall, Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Fluid, Electrolytes, and Acid-Base Disorders

• 1102 Fluid, Electrolyte, and Acid-Base Disorders: Clinical

Author

• Hulwi, Hasan, New York Presbyterian Queens Hospital, Flushing, New York, United States

Hasan Hulwi, MD

Introduction

Bartter syndrome is a rare inherited tubulopathy characterized by salt wasting, hypokalemia, and metabolic alkalosis. Acquired Bartter-like syndromes have been reported in association with nephrotoxic agents such as polymyxins. Polymyxin-induced nephrotoxicity, which affects up to 60% of patients, involves proximal tubular accumulation via megalin/PEPT2-mediated endocytosis, leading to tubular injury. We present a case of a 77-year-old female who developed Bartter-like syndrome following six days of polymyxin-B therapy, highlighting a rare but significant adverse effect.

Case Description

A 77-year-old female with a past medical history of hypertension, hyperlipidemia, deep vein thrombosis, prediabetes, and obesity, who presented to ER with asymptomatic hypokalemia (serum potassium: 2.5 mmol/L), was detected on routine outpatient labs. She had recently been hospitalized for a left lower extremity cellulitis and was treated with initially treated with piperacillin/tazobactam, followed by Polymyxin-B and Meropenem. Patient was discharged to continue intravenous meropenem, polymyxin-B (100mg IV BID), and the addition of oral doxycycline for two weeks. During her stay at a rehabilitation facility, routine bloodwork revealed persistent hypokalemia. Laboratory investigations are shown in Table 1.

Discussion

This case illustrates a polymyxin rare but important adverse effect: an acquired Bartter-like syndrome. We presume that the patient developed persistent hypokalemia, hypomagnesemia, and hypocalcemia, with borderline high bicarbonate, approximately 20-21 days after polymyxin-B exposure. Despite preserved renal function at the time of discharge and readmission, her electrolyte panel was consistent with a Bartter-like syndrome. Polymyxin-induced nephrotoxicity is well-documented, with incidence rates up to 60%, typically manifesting as acute tubular injury. Its ability to mimic Bartter syndrome through distal tubular dysfunction is less commonly recognized.

Table 1 – Serum electrolytes

Digital Object Identifier (DOI)

• doi: 10.1681/ASN.2025s22h98gw