A clinical study of upper urinary tract calculi treated with extracorporeal shock wave lithotripsy: association with bacteriuria before treatment.

To study the characteristics of upper urinary tract calculi associated with bacteriuria, we determined the relationships between the frequency of bacteriuria and some clinical factors such as location and size of calculi. Nine hundred and fifty-eight patients, 596 with renal calculi and 362 with ureteral calculi, were subjects in the present study. Bacteriuria was found in 75 patients, 57 with renal calculi (10%) and 18 with ureteral calculi (5%). The frequency of bacteriuria was significantly higher in patients with renal calculi than in those with ureteral stones (p < 0.05). In the patients with renal calculi, bacteriuria was most frequently associated with stones having a diameter of > 30 mm (19%), and secondarily with stones of 20-30 mm (12%). In contrast, the presence of bacteriuria was not related to the size of ureteral calculi. In conclusion, patients with renal stones of > 20 mm diameter have an increased risk of bacteriuria.