The changing urodynamic pattern from infancy to adolescence in boys with posterior urethral valves

Objective To determine whether bladder dysfunction in boys with posterior u rethral valves (PUV) changes from a uniform pattern of hypercontractility d uring infancy to the hypocontractility found in adolescence, by reviewing s erial urodynamic studies. Patients and methods Thirty boys with PUV and no voiding symptoms underwent a total of 86 urodynamic tests (mean 2.8 each). The first urodynamic study was undertaken at 1-4 years of age in 15 boys and at 5-13 years in 15. The y were re-evaluated at least 3 years later; 15 patients underwent the first and last urodynamic study, respectively, at a mean age of 2.8 and 7.7 year s (group A), 10 boys at 6.2 and 8.5 years (group B) and five at 9.4 and 15. 2 years (group C). In 10 boys aged >5 years the first and last pressure-flo w studies (PFS) were analysed using an advanced analysis (PFA) to better id entify hypocontractility. Results Bladder dysfunction was found in 21 of 30 (70%) boys at the first e valuation and in 18 (60%) at the last. In 25 boys the urodynamic pattern ch anged. Of the 15 boys in group A, 10 of 12 who had hypercontractility chang ed to normal (seven), low compliance (one) or hypocontractility (two), and two remained stable; two of the remaining three with normal urodynamic stud ies changed to hypocontractility, while one was unchanged. Among the 10 boy s in group B, six with hypercontractility changed hypocontractility (three) ; to normal (three) or hypocontractility (three); two with normal urodynami c findings and one with low compliance changed to hypocontractility. Of the five boys in group C who showed severe hypocontractility after puberty, th ree had a normal pattern, one low compliance and one hypercontractility bef ore puberty. The PFA showed a 'weak' detrusor in four of the seven boys who were considered normal on standard PFS. At the urodynamic follow-up, the P FA pattern changed to a 'weak' detrusor in four boys who had a normal (two) or strong (two) detrusor at the first evaluation. Conclusions Bladder dysfunstion in boys with PUV changes during childhood a nd through adolescence. The urodynamic pattern of hypercontractility genera lly found soon after valve ablation gradually changes to hypocontractility in many boys and this pattern seems to be the rule after puberty. The evide nce from this series supports the hypothesis that long-term detrusor hypera ctivity in boys with PUV leads to detrusor failure, but a longitudinal 15-y ear follow-up from birth to puberty is needed to validate this concept.