Document Type

Conference Proceeding

Publication Date



Introduction: Trimethoprim-sulfamethoxazole is a commonly used antibiotic for treatment of urinary tract infections (UTIs). It is also commonly used to treat nocardia infections. Less common are reports of nephrolithiasis consisting purely of N4-acetyl-sulfamethoxazole, the primary metabolite of trimethoprim-sulfamethoxazole. Case: A 70-year-old male with history of mantle cell lymphoma and T-cell leukemia treated with bone marrow transplant now with nocardia lung infection receiving trimethoprimsulfamethoxazole for the past 6 months who presented to the emergency room with confusion and a fall. He had no prior history of nephrolithiasis, but during hospitalization developed renal colic and was found to have obstructing right proximal ureteral calculi associated with declining renal function. The patient required ureteral stenting followed by interval ureteroscopy. During ureteroscopy, numerous small calculi were seen in the proximal ureter that were soft and dark orange in color. When he presented for stent removal 2 weeks postoperatively his stent was unretrievable and had to be removed later under general anesthesia. Stone analysis showed 100% N4-acetyl-sulfamethoxazole. The patient was referred to infectious disease for adjustment of antibiotic regimen. Conclusion: Pure N4-acetyl-sulfamethoxazole stones are exceptionally rare and have only been documented in a few case reports in patients receiving long term sulfonamides. This case provides an important reminder that although uncommon trimethoprimsulfamethoxazole related stones can lead to significant morbidity. Alternative antibiotics and treatment including alkalinization of the urine and diuresis can be considered for stone prevention and dissolution


The 95th Annual Meeting of the North Central Section of the AUA, Chicago, IL, October 6-9, 2021.

Included in

Urology Commons