Changes in the threshold voltage and alterations of smooth-muscle physiology after bladder outlet obstruction

Current perspectives on congenital obstructive nephropathy

Congenital obstructive nephropathy is the leading cause of chronic renal disease in children. As a result, it represents a tremendous societal burden in terms of morbidity and mortality, as well as in health care expenses of caring for children with chronic kidney disease and end-stage renal disease. The various diagnostic, prognostic, and therapeutic challenges associated with congenital obstructive nephropathy highlight the importance of developing effective experimental models for studying this disease process. In this review, we define the clinical entity that is congenital obstructive nephropathy, outline the current standards of diagnosis and care, and discuss the utilization of current experimental models designed to help clarify some of the clinical conundrums associated with this important disease.

Late urodynamic findings after treating traumatic rupture of the posterior urethra in boys

OBJECTIVE

To investigate lower urinary tract (LUT) functions in a prospective study in boys treated for posterior urethral distraction (PUD), as posterior urethral stricture, erectile dysfunction and incontinence can occur after various treatments for this rare injury in children.

PATIENTS AND METHODS

Eleven boys were treated for PUD and resultant stricture between 1980 and 2000. Their age, the cause of trauma, extent of injury, previous treatment, and continence status were evaluated, and a urodynamic study conducted. Controls were 12 age-matched males who underwent similar cystometrography (CMG) and uroflowmetry.

RESULTS

The mean (SD) age at injury was 8 (4) years and the cause was traffic accident in nine and crush injury in two boys. Seven boys had an isolated urethral rupture, two also had a bladder neck injury and two also had a perforated bladder. No gross neurological impairment developed after trauma. Voiding cysto-urethrograms after initial therapy showed vesico-ureteric reflux in five boys, but in only one at the time of the urodynamic studies. At the time of urodynamic study, the mean (SD) age of the patients was 15 (6) years; seven were fully continent, one had intermittent leakage, two were incontinent, and one had nocturnal enuresis. CMG-electromyography (EMG) showed a reduced maximum cystometric capacity in nine patients, reduced compliance in 10, stable detrusor in 11, synergic detrusor-sphincter activity in 11, and residual urine in one. The uroflowmetry-EMG study showed prolonged voiding time and flow time, decreased maximum flow urinary rate (Q(max)) and mean flow rate (Q(avg)). The shape of the flow curve showed an uninterrupted low-amplitude pattern. Comparing these patients with age-matched controls, CMG and uroflowmetry studies showed that the maximum cystometric bladder capacity, compliance, Q(max) and Q(avg) were all significantly lower in patients with PUD, while voiding time and flow time were significantly higher.

CONCLUSION

The LUT deteriorates after treating PUD in boys. CMG and uroflowmetry findings are consistent with partial anatomical obstruction distal to the bladder. Our results are preliminary and full urodynamics, including pressure-flow studies, will be useful to support this conclusion. A urodynamic study should be integral in the management of PUD.