Bacteriuria following extracorporeal shock-wave lithotripsy in patients whose urine was sterile before the procedure

Incidence of infectious complications after extracorporeal shock wave lithotripsy in patients without associated risk factors

PURPOSE

We determined the incidence of infectious complications (asymptomatic bacteriuria, urinary tract infection and urosepsis) in patients without associated risk factors treated with extracorporeal shock wave lithotripsy.

MATERIALS AND METHODS

We performed an observational, prospective cohort study between October 2010 and June 2013. We included all patients without risk factors who were treated with extracorporeal shock wave lithotripsy for kidney or ureteral lithiasis. All patients underwent urine culture 5 days before the procedure. Another urine culture was performed 7 days after lithotripsy. No patient received antibiotics.

RESULTS

Initially 366 patients with a mean ± SD age of 53 ± 13 years were enrolled in the study. A total of 64 patients (17.5%) underwent extracorporeal shock wave lithotripsy with a previously placed Double-J® stent. After lithotripsy urine culture was positive in 20 patients (5.8%), of whom 4 (1.2%) presented with symptomatic urinary infection and the remaining 4.6% showed no symptoms. Urosepsis did not develop in any case. In our study patient age was an independent risk factor for bacteriuria after lithotripsy.

CONCLUSIONS

The incidence of infectious complications after extracorporeal shock wave lithotripsy in patients without risk factors is low. This leads us to conclude that without defined risk factors antibiotic prophylaxis is not justified. Also, elderly patients were more at risk for bacteriuria after extracorporeal shock wave lithotripsy and, thus, for a possible infectious complication.

Urinary Tract Infections after Extracorporeal Shock Wave Lithotripsy

Extracorporeal shock wave lithotripsy (ESWL) has been using since a long time in the treatment of urolithiasis; until now it is not universally stated if such a procedure represents a risk factor for the development of complications (such as pyelonephritis) and if the same procedure needs an antimicrobial prophylaxis. We began a prospective study in order to evaluate the clinical and microbiological follow-up of all the patients undergoing ESWL at the Centre of urologic lithotripsy of the University of Pisa into a two months period.

Methods

Fifty-four consecutive patients were enrolled (38 males and 16 females). All the patients were studied, examining their urine samples before ESWL and after one week and evaluating their risk factors for urinary tract infections.

Results

12 (22.2 %) out of 54 patients had a significant bacteriuria (≥ 104 CFU/mL) before undergoing ESWL; such bacteriuria persisted in eight of the twelve patients even though they received an appropriate antimicrobial therapy. 41 (75.9%) patients without a significant bacteriuria at the enrollment remained asymptomatic –with sterile urine- after ESWL and they did not receive therapy. One patient with multiple stones, who had a clinical history of previous urinary infections, developed an acute pyelonephritis after ESWL when she stopped the antibiotic terapy.

Conclusions

Such preliminary data seem to show that the risk of developing urinary infections after ESWL is represented primarily by a history of previous urinary infections and by the presence of an asymptomatic urinary tract infection before ESWL. The decision about the need of an antimicrobial prophylaxis should be taken in every single case basing on the peculiar clinic history of the patient.

[Metastatic cerebral abscess from Klebsiella pneumoniae after extracorporal shock wave lithotripsy for kidney stone (a case report)]

Extra-corporeal Shock Wave Lithotripsy (ESWL) is widely used to treat urinary calculi. With increasing numbers of ESWL, more patients prone to infectious complications. A 62-year-old man presented with cerebral abscess following ESWL. The authors discuss presenting conditions, risk factors and preventive measures.

Antimicrobial prophylaxis prior to shock wave lithotripsy in patients with sterile urine before treatment: a meta-analysis and cost-effectiveness analysis

OBJECTIVES

To determine the efficacy and cost-effectiveness of routine antimicrobial prophylaxis prior to shock wave lithotripsy (SWL) in patients with a sterile pretreatment urine culture.

METHODS

A structured MedLine search revealed eight prospective, randomized, controlled trials (RCTs) of active treatment versus placebo or no treatment (n = 885) and six clinical series (non-RCTs; n = 597) addressing the use of antimicrobial prophylaxis for SWL. A meta-analysis was performed on the eight RCTs, with the primary outcome being the diagnosis of a urinary tract infection (UTI) post-SWL. A cost analysis was performed comparing a prophylactic strategy (prophylaxis for every patient and treatment for post-SWL UTIs) with a treatment-only strategy for post-SWL UTIs using various antimicrobial combinations and the median probability of post-SWL UTIs determined by meta-analysis.

RESULTS

The incidence of post-SWL UTIs ranged from 0% to 28% in the control group and from 0% to 7.7% in the patients who underwent prophylaxis. Combining the placebo/no-drug treatment arms in the six RCTs by meta-analysis (Bayesian analysis) resulted in a median probability of a post-SWL UTI of 5.7% (95% confidence interval [CI] 3.8% to 8.4%). For the drug treatment arms, the median probability of a UTI was 2.1% (95% CI 0.9% to 3.6%). Relative risk (RR) analysis resulted in an overall RR of post-SWL UTIs with prophylaxis versus without prophylaxis of 0.45 (95% CI 0.22 to 0.93) (P = 0.0005). Depending on the antimicrobial regimen used for prophylaxis and treatment, a prophylactic strategy added minimally to the overall treatment cost of SWL, and proved cost beneficial when taking into consideration serious UTIs requiring inpatient treatment.

CONCLUSIONS

A policy of antibiotic prophylaxis prior to SWL in patients with sterile pretreatment urine cultures is efficacious in reducing the rate of post-SWL UTIs. Discounting inpatient episodes for sepsis and acute pyelonephritis, however, the strategy is not cost-effective. In contrast, using literature-derived incidence estimates for post-SWL urosepsis or pyelonephritis necessitating inpatient treatment, prophylaxis becomes both efficacious and cost-effective, and thus constitutes a dominant strategy.