Polymyxin-B induced Bartter-like syndrome: an unusual adverse effect.

Introduction and importance: Bartter syndrome is a rare autosomal recessive disorder affecting renal tubular function leading to disturbances in electrolyte and volume homeostasis. It can also manifest as Bartter-like syndrome (BLS), a rare side effect of certain medications. Polymyxin-B, an antibiotic used to treat multidrug-resistant infections is infrequently associated with BLS. Hence, early diagnosis of this adverse effect is crucial to prevent severe electrolyte imbalances. Case presentation: A 73-year-old female with coronary artery disease, chronic obstructive pulmonary disease, and hyperlipidemia, presented with fever, respiratory distress, and hypoxia on mechanical ventilation. Initial labs showed leukocytosis, anemia, and normal potassium. Despite receiving broad-spectrum antibiotics there was no improvement in her clinical condition. A sputum culture revealed pandrug-resistant Acinetobacter baumannii, sensitive only to Polymyxin-B. After six days of receiving polymyxin-B, the patient developed fever, hypotension, hypokalemia, hypomagnesemia, and polyuria. Urine studies indicated increased potassium excretion. A diagnosis of BLS was made. Polymyxin-B was discontinued, and the patient's electrolytes normalized. She was discharged with daily potassium and magnesium supplements. Clinical discussion: BLS can result from polymyxin-B-induced tubular dysfunction characterized by hypokalemia and hypomagnesemia. Early recognition allowed for the timely discontinuation of polymyxin-B, which rapidly reversed her electrolyte disturbances. Conclusion: This case underscores the importance of recognizing polymyxin-B-induced BLS. Clinicians should be vigilant for electrolyte disturbances in patients receiving treatment with polymyxin-B, ensuring timely interventions to mitigate adverse outcomes.