The valve bladder syndrome: pathophysiology and treatment with nocturnal bladder emptying.

PURPOSE: We determine the etiology and treat the specific pathophysiology of the valve bladder syndrome.

MATERIALS AND

METHODS

Defined as persisting or progressive severe hydroureteronephrosis without residual or recurrent obstruction, the valve bladder syndrome developed in 18 boys who underwent successful ablation of the posterior urethral valve. Serial radiographic, renal function, renographic, urodynamic and perfusion studies were performed for a mean time of 11 years.

RESULTS

The cause of the valve bladder syndrome proved to be sustained bladder over distention due to a combination of polyuria with 24-hour urine volume greater than 2 l. in 10 boys, impaired bladder sensation in 18 and residual urine volume in 14. Treatment of over distention during the daytime alone was unsuccessful. Nocturnal bladder emptying was performed with an indwelling nighttime catheter, intermittent nocturnal catheterization and/or frequent nocturnal double voiding. Hydronephrosis markedly improved once nocturnal bladder emptying was started and was comparable to the results after urinary diversion.

CONCLUSIONS

The valve bladder syndrome is not due to a permanent prenatal alteration in bladder anatomy and function. Instead, it appears to result from sustained postnatal bladder over distention due to a combination of polyuria, impaired bladder sensation and residual urine volume, which represent sequelae of prenatal valve injury. These factors synergize to prevent bladder normalization after valve ablation and progressively reduce functional bladder capacity to maintain bladder over distention. Bladder decompensation, upper tract dilation, and renal injury develop and characterize the valve bladder syndrome. Because current therapy, including intermittent catheterization, leaves the bladder full throughout the night, it remains markedly over distended. Nocturnal bladder emptying is the specific antidote for this pathophysiological situation, and results in prompt and impressive improvement or elimination of hydronephrosis in these and similar groups of patients. This response to nocturnal bladder emptying suggests that the bladder is not the primary cause for the valve bladder syndrome.