Prevalence of hypercontractility in male and female infants with vesico-ureteral reflux.

PURPOSE: To establish whether infants with vesico-ureteral reflux (VUR) have bladder dysfunction, with difference in gender, age at presentation and severity. PATIENTS AND METHODS: 37 infants (24 male and 13 female) aged 2 to 24 months with II degrees to V degrees degree VUR underwent cystometry. Of those, 10 underwent natural filling cystometry. We considered: instability and maximal voiding detrusor pressure (VDP) to be "high" when it exceeded 90 cm H2O. We defined hypercontractility as high VDP and/or instability. RESULTS: The prevalence of hypercontractility was 75% (18/24) in male and 46% (6/13) in female infants (p<0.004). High VDP was found in 50% (12/24) of male and 7% (1/13) of female patients (p < 0.001); no significant difference was found between male (25%) and female ones (38%) with instability alone.The mean VDP was significantly higher in male than in female infants (p < 0.001), in patients < 1 year of age than in older ones (p<0.001) and in severe than in moderate reflux (p<0.006). The mean voiding detrusor pressure of male infants was higher in severe (108+/-46cm H2O) and bilateral (101.3+/-44cm H2O) than in moderate (76+/-24 cm H2O) and unilateral (73.7+/-24 cm H2O) and in infants < 1 year of age (101.7+/-42 cm H2O) than in older ones (70.2+/-21 cm H2O). Natural filling cystometry confirmed the results of standard urodynamic studies. CONCLUSIONS: Bladder dysfunction is confirmed also in infants with reflux, particularly in male younger patients, and it differs in gender. The pathogenesis of congenital reflux is not always a feature of malformation of the vesico-ureteral junction; therefore, patients with bladder dysfunction must be identified early.