Recurrent urinary tract infection (rUTI) is one of the most common problems in urological outpatient clinic that should not be underestimated. The etiology of rUTIs is not fully understood. Previous studies on voiding dysfunction causing rUTIs are rare. Patients with lower urinary tract dysfunction (LUTD) tend to have abnormal voiding patterns and large post-void residual volume (PVR). The impaired bladder emptying may play an important role in urothelial barrier dysfunction, increasing the susceptibility to bacterial colonization and subsequent UTI. This study aimed to evaluate the voiding dysfunctions identified by video-urodynamic study (VUDS) in women with rUTIs. We also investigated the treatment outcome after individualized treatment.

Over a 10-year retrospective study period, 98 female patients with rUTIs underwent VUDS in our hospital were included. Recurrent UTI was defined as at least three UTI episodes over the past one year or two episodes over 6 months. All the underlying disease, urine analysis reports, urine culture results, the results of VUDS findings and the treatment outcome of voiding dysfunction were carefully reviewed and analyzed.

Of the 98 female patients with rUTIs, the mean age was 64.2 ± 15.6 years. Voiding dysfunctions were found in 89 (90.8%) of the patients, including bladder neck dysfunction in 19 (19.4%), detrusor hyperactivity with impaired contractility in 10 (10.2%), detrusor overactivity in 37 (37.8%), detrusor underactivity in 20 (20.4%), dysfunctional voiding in 24 (24.5%), hypersensitive bladder in 22 (22.4%), and poor relaxation of the external sphincter in 19 (19.4%). Only 9 (9.2%) patients had normal urodynamic tracings (Fig.1). Compared with the control group, voiding dysfunctions in women with rUTIs have significant smaller cystometric bladder capacity (338.2 ± 138.0 mL), Qmax (11.9 ± 7.6 mL/s), corrected Qmax (0.6 ± 0.4 mL/s), voided volume (223.5 ± 139.9 mL/s), and significantly higher Pdet (23.1 ± 19.0 cmH2O), and larger PVR (119.3 ± 141.0 mL/s ) (Table 1). Only 6 (6.1%) patients with rUTIs were totally free from urinary tract infection after VUDS followed by individualized treatment.

Voiding dysfunction results in larger PVR, high Pdet and small bladder capacity, which may impair barrier function of the bladder urothelium. Recurrent UTI in these women might not be adequately eradicated unless the voiding dysfunction has been solved.

High incidence of urodynamic disorders was identified in women with rUTIs. Despite individualized treatment was given based on the VUDS findings, only few patients could be free from UTI. Factors other than voiding dysfunction should be considered in order to cure rUTIs.