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

Purpose: To establish whether infants with vesico-ureteral reflux (VUR) hav e bladder dysfunction, with difference in gender, age at presentation and s everity. Patients and Methods: 37 infants (24 male and 13 female) aged 2 to 24 month s with II degrees to V" degree VUR underwent cystometry. Of those, 10 under went natural filling cystometry. We considered: instability and maximal voi ding detrusor pressure (VDP) to be "high" when it exceeded 90 cm H2O. We de fined hypercontractility as high VDP and/or instability. Results: The prevalence of hypercontractility was 75% (18/24) in male and 4 6% (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 m ale infants was higher in severe (10 +/- 46cm H2O) and bilateral (101.3 +/- 44cm H2O) than in moderate (76 +/- 24 cm H2O) and unilateral (73.7 +/- 24 c m H2O) and in infants < 1 year of age (101.7 +/- 42 cm H2O) than in older o nes (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 pathog enesis of congenital reflux is not always a feature of malformation of the vesico-ureteral junction; therefore, patients with bladder dysfunction must be identified early.