Bladder dynamics and vesicoureteral reflux: Factors associated with idiopathic lower urinary tract dysfunction in children

Purpose: The objective of this study was to determine the clinical, demographic, urodynamic and prognostic characteristics related to vesicoureteral reflux among patients with idiopathic lower urinary tract dysfunction. Materials and Methods: We retrospectively reviewed the records of 348 children with idiopathic detrusor overactivity or dysfunctional voiding who had been examined for vesicoureteral reflux between 1995 and 2005 at a university hospital. Demographic, clinical and urodynamic parameters were compared between groups according to the presence, grade, laterality and resolution of vesicoureteral reflux. Results: Among the 348 patients 8 infants were excluded from statistical analysis and are discussed separately. Among the 340 remaining patients 1 year and older vesicoureteral reflux was documented in 155 (46%), of whom 32% had bilateral reflux. Of the overall cases 60% were grade III or higher. Mean age in the refluxing group (6.5 +/- 2.8 years) was significantly lower than in the nonrefluxing group (7.6 +/- 2.5 years, p<0.001). Continent children presented with a significantly higher rate of vesicoureteral reflux compared to incontinent children (74% vs 42%, p<0.001). Among the patients who had urinary tract infection the presence of reflux increased the rate of renal cortical abnormalities (45% vs 17%, p 0.001). However, among patients who were free of urinary tract infection the presence of reflux was not associated with cortical abnormalities (25% vs 24%, p>0.05). Median maximum filling pressure was higher in the refluxing group compared to the nonrefluxing group (40.0 vs 34.0 cm H2O, p<0.001). Detrusor overactivity and dysfunctional voiding showed similar rates for development of vesicoureteral reflux. Reflux was resolved with medical treatment in 40% of the patients. The resolution rate was significantly higher in children with nondilating reflux and initial lower median cystometric bladder capacity. Conclusions: Vesicoureteral reflux is associated with daytime incontinence, urinary tract infection, younger age and renal cortical abnormalities among patients with idiopathic lower urinary tract dysfunction. Increased intravesical pressures seem to be the primary factor for inducing reflux in idiopathic lower urinary tract dysfunction. Initial bladder capacity predicts the resolution of reflux.