Improved renal function following aggressive treatment of urolithiasis and concurrent mild to moderate renal insufficiency.

To our knowledge the prevalence of urinary stone disease and concurrent mild to moderate renal insufficiency has never been reported. A review of our last 2,000 urinary stone patients identified 33 (1.65%) with serum creatinine levels of 2.0 mg./dl. or greater at presentation. Chemical composition, location and complexity of the calculi, types of procedures required to render the patient stone-free and the effect of surgical intervention (independent of relief of obstruction) on renal function were evaluated. Mean serum creatinine level before surgical intervention and after placement of a ureteral stent or percutaneous nephrostomy tube in patients with evidence of obstruction was 3.2 mg./dl. (range 2.0 to 7.5). Complete or partial staghorn calculi were found in 21 of the 33 patients (64%), including 8 with bilateral staghorn calculi. Seven patients required 1 procedure, 1 required urinary alkalization alone and the other 25 required an average of 3.5 procedures each. Stone analysis revealed struvite, mixed calcium and uric acid to be the most common types. Followup creatinine values (the latest available within 1 year) and corresponding creatinine clearances showed remarkable improvement. The mean decrease in serum creatinine level was 1.2 mg./dl. (p < 0.001). There was no statistically significant difference in the rate of decrease between patients with pretreatment serum creatinine levels of 2.0 to 2.9 mg./dl. and those with initial values of 3.0 or more. Renal calculi and concurrent mild to moderate renal insufficiency warrant aggressive treatment. Patients demonstrate significant improvement in renal function independent of relief of obstruction.