Ultrasound bladder measurements in children with severe primary nocturnal enuresis: pretreatment and posttreatment evaluation and its correlation with treatment outcome.

PURPOSE

Results from our previous study demonstrated a high predictive value using ultrasound bladder measurements to identify abnormal bladder function in children with enuresis or urinary tract infection. We prospectively evaluated the role of ultrasound measured bladder parameters for the assessment of bladder dysfunction and posttreatment bladder functional changes (if any), and their correlation with treatment outcome in children with primary nocturnal enuresis.

MATERIALS AND METHODS

Patients presenting with severe primary nocturnal enuresis (more than 3 wet nights weekly) were prospectively recruited. At study entry each patient underwent ultrasound, and natural and conventional filling cystometric studies. Bladder volume and wall thickness index was calculated based on ultrasound studies and classified as thick (less than 70), normal (70 to 130) or thin (more than 130). The criteria for diagnosing urodynamic patterns included normal, overactive and underactive detrusor activity. Correlation between the ultrasound measured parameters and urodynamic findings was then evaluated. Patients were treated based on our standardized treatment protocol. Bladder measurements were repeated in those children who had completed treatment. The McNemar test was used for comparing posttreatment changes in bladder measurements corresponding to treatment outcome in different groups, and p values less than 0.05 were regarded as statistically significant.

RESULTS

A total of 35 children (23 males, 12 females; mean age 9.03 years) were prospectively recruited. At study entry bladder volume and wall thickness index was normal in 8 patients, less than 70 in 24 and more than 130 in 3. When bladder volume and wall thickness index was correlated with ultrasound 87.5% of the patients with a normal index exhibited a normal bladder pattern on imaging. In addition, 96% of the patients with an index of less than 70 exhibited bladder overactivity on ultrasound. All of the children with a normal index had either a complete or good response to treatment, whereas 62.5% of those with an index of less than 70 did not respond to treatment. On followup bladder dysfunction had resolved in 37.5% of the children with an initial index of less than 70, all of whom had a good response to the treatment. Bladder dysfunction persisted in 62.5% of the patients, all of whom had partial or no response to treatment (p <0.001).

CONCLUSIONS

Ultrasound measured bladder parameters correlated well with ultrasound findings, changes in bladder function and treatment outcome in children with primary nocturnal enuresis. This study further confirms that this specially designed ultrasound protocol can provide useful predictive clues that may be helpful in differentiating between various treatment subtypes, guiding clinical management and minimizing the need for invasive urodynamic studies.