Successful endourological treatment for a rare case of atazanavir-induced urinary stones

Atazanavir, an anti-HIV drug, induces urinary stone formation. We herein report a case of atazanavir-induced bilateral ureteral stones treated with endourological procedures.

A 47-year-old male patient on atazanavir was admitted with right flank pain. The patient's serum creatinine level was 3.60 mg/dL. Plain computed tomography showed bilateral hydronephrosis. The left upper ureter was obstructed by a 13 × 12 × 9-mm mass, which had very low CT attenuation values. The lower part of the right ureter was obstructed, but no mass was observed. Given his medical history, we suspected bilateral ureteral obstruction caused by drug-induced stones. A ureteral stent was successfully inserted on the right side, but not on the left side. Thereafter, a bilateral ureteroscopic lithotripsy was performed. Infrared spectrophotometry revealed that the stone component was atazanavir.

Understanding the characteristics of these rare drug-induced stones will aid in the proper early diagnosis and treatment.