Acquired Bartter-Like Syndrome Associated with Gentamicin Administration

Although acute nonoliguric renal failure is a well-known nephrotoxic effect of aminoglycoside antibiotics, less recognized is acquired Bartter-like syndrome. Herein, we describe four female patients who presented with marked paresthesia, muscle weakness, and tetany following gentamicin therapy with total dose ranging from 1.2 g to 2.6 g. All were normotensive. Biochemical abnormalities included hypokalemia (K+ 1.8-2.3 mmol/L), metabolic alkalosis (HCO3− 31.9-34.2 mmol/L), hypomagnesemia (Mg2 + 0.9-1.2 mg/dL), hypermagnesiuria (fractional excretion of Mg 3-6%), hypocalcemia (free Ca2 + 2.0-4.1 mg/dL), and hypercalciuria (molar ratio of Ca2 +/creatinine 0.23-0.53), all consistent with Bartter-like syndrome. Serum immuno-reactive parathyroid hormone concentration was low despite the hypocalcemia. The Bartter-like syndrome lasted for 2 to 6 weeks after cessation of gentamicin, coupled with supplementation of K+, Ca2 +, and Mg2 +. These biochemical abnormalities resembled those seen in patients with gain-of-function mutations in the calcium-sensing receptor. We hypothesize that gentamicin, a polyvalent cationic molecule, induces the action of calcium-sensing receptor on the thick ascending loop of Henle and distal convoluted tubule to cause renal wasting of Na+, K+, Cr, Ca2 +, and Mg2 +.