Bladder dysfunction in boys with posterior urethral valves.

UNLABELLED

Posterior urethral valve (PUV) is a congenital urethral obstruction affecting boys. As a result of the obstruction in fetal life, these boys often have a persisting bladder dysfunction, which is one of the main causes of the late onset renal failure seen in 1/3 of the boys and is also responsible for the delayed achievement of continence. The aim of this study was to characterize the bladder dysfunction from infancy through childhood and adolescence in boys with neonatally diagnosed PUV with the intention of designing a bladder treatment regimen starting in infancy. Paper I: 16 infant boys with PUV were followed with repeated standard cystometries. At presentation the bladders were hypercontractile with low capacity. During the first three years of life the urodynamic pattern changed, with vanishing hypercontractility and increasing bladder capacity, even though the instability remained unchanged. Paper II: 12 boys were followed with standard cystometries between 4 and 12 years of age and compared with a group of 6 postpubertal boys with PUV. The urodynamic pattern continued to change, with decreasing instability and contractility. A major problem was emptying difficulties. Paper III: The voiding pattern during the day versus the night in 10 incontinent and 6 continent boys with PUV was evaluated by long-term natural filling cystometry. The voiding pattern, with small frequent voidings during the day and few or no voidings during the night with high bladder volumes in the morning, could be explained by pronounced instability during the day whereas the bladders were stable during the night. Paper IV: The method of "4 hour voiding observation" was presented as a non-invasive method for basic assessment of bladder function in non-toilet trained children and the voiding pattern in 43 healthy infants was demonstrated. Paper V: The voiding pattern, with special attention to emptying difficulties, in 25 small children with PUV compared to healthy children of corresponding age, was evaluated with the "4 hour voiding observation."

CONCLUSIONS

Boys with PUV have a bladder dysfunction with a changing urodynamic pattern over time with decreasing contractility and instability. In small boys the instability was pronounced during daytime while during the night the bladders were mainly stable. Most boys with PUV and bladder dysfunction end up with a deconpensated bladder. A major problem was bladder emptying difficulties. The "4 hour voiding observation" is an excellent non-invasive method of identifying those patients in need of early bladder treatment, i.e. with clean intermittent catheterisation.