Aminoglycoside nephrotoxicity following single-dose cystoscopy prophylaxis

OBJECTIVE: To report a case of gentamicin-associated acute tubular necrosis following single-dose exposure. SETTING: Central-city, university-affiliated teaching hospital. PATIENT: An 82-year-old man, admitted for evaluation of shortness of breath, appetite reduction with weight loss, and stable renal insufficiency, developed urinary retention, which prompted a urologic evaluation followed by a cystoscopy. INTERVENTIONS: A single 1.6-mg/kg (actual body weight) dose of gentamicin was administered as prophylaxis prior to this procedure. RESULTS: A significant decline in renal function was observed 48 hours following gentamicin administration. A nephrology evaluation excluded pre- and postrenal causes and attributed this episode of nonoliguric acute tubular necrosis to a single dose of gentamicin. CONCLUSIONS: Although not consistent with currently proposed mechanisms and reported onset of aminoglycoside-induced nephrotoxicity, an etiology other than that concluded by this case report appears unlikely.