Incidence of urinary tract infection in patients without bacteriuria undergoing SWL: comparison of stone types.

Extracorporeal shockwave lithotripsy (SWL) currently is accepted as the preferred treatment for most renal and upper ureteral calculi. However, little is known about the infection risks of SWL. In this study, the incidence and severity of urinary tract infection in 117 patients with renal calculi undergoing SWL were evaluated and the stone characteristics of those with and without infection were compared. The patients were followed clinically and bacteriologically 1 and 14 days after the procedure. Bacteriuria was noted in six patients within 24 hours after SWL. No bacteriuria was noted 2 weeks later. Of these patients, three were symptomatic (including dysuria, burning, and fever >38 degrees C). No patient was hospitalized. We found no significant correlation between the occurrence of bacteriuria and the number or size of the stones (P > 0.05), nor was there any correlation between bacteriuria and the stone-free rate or the location of the calculi (P > 0.05). However, there was a significantly higher risk of urinary tract infection in patients with struvite stones than in those with other types of stones (17.3% v 2.1%). In patients with infection stones, prophylactic antimicrobial chemotherapy is necessary even if bacteriuria is not present before SWL.