This Month in Pediatric Urology

Article Outline

• Testicular Microlithiasis in Asymptomatic Children
• Nomograms for Predicting Resolution of Vesicoureteral Reflux
• Cystatin-C and Outcome of Prenatal Infravesical Obstruction
• Efficacy and Safety of Oxybutynin in Children With Neurogenic Detrusor Overactivity
• Pediatric Urology and the Internet
• Copyright

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Testicular Microlithiasis in Asymptomatic Children 

Testicular microlithiasis is considered a benign disorder in the pediatric population yet there is little information regarding the prevalence in asymptomatic boys. Its prevalence is reported to be 1.9% in symptomatic boys, 0.6% to 9% in symptomatic men and 2.4% to 5.6% in asymptomatic men. To determine the incidence of testicular microlithiasis in an asymptomatic population, Goede et al (page 1516) from Alkmaar, the Netherlands invited more than 2,600 boys to participate in a testicular screening study, of whom 670 responded. The boys, 98% of whom were white, had no history of gonadal surgery, hernia, hydrocele or undescended location of the testis. All boys underwent testicular ultrasonography. Microlithiasis was defined as echogenic foci measuring 1 to 3 mm. Classic microlithiasis was defined as greater than 5 foci and limited microlithiasis was defined as fewer than 5 foci. Classic testicular microlithiasis was identified in 16 boys (2.4%) with a mean age of 11.7 years.

The presence of testicular microlithiasis increased with age from 0.5% in the younger boys (age less than 6 years) to 4% in the older boys (age greater than 12 years). The authors developed a grading system of microlithiasis but it did not provide any further insight into the prevalence when patients were stratified by age. Screening scrotal ultrasound confirmed the absence of testicular microlithiasis in the male siblings of 9 of the 16 boys. The 2.4% prevalence rate in this study is similar to that reported in asymptomatic men. The authors do not believe that classic testicular microlithiasis is a prerequisite to a premalignant lesion. They do recognize that their findings are limited to white children and, therefore, ethnicity may have a role in the development of microlithiasis.

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Nomograms for Predicting Resolution of Vesicoureteral Reflux 

Estrada et al (page 1535) from Boston, Massachusetts developed a nomogram for predicting yearly resolution of primary vesicoureteral reflux. This information was culled from an electronic longitudinal database allowing the authors to assess 2,462 children with vesicoureteral reflux. The advantage of a reliable nomogram has obvious benefits when counseling families regarding the pros and cons of prophylactic antibiotics and operative intervention based on the potential for resolution. The end point was to define factors that influence the resolution of reflux based on reliable, universally obtained data. Only patients with primary vesicoureteral reflux were included in the study. Reflux was graded based on the international study and reflux resolution was confirmed following 1 negative voiding cystourethrogram or radionuclide cystogram. Of the children 26% had undergone surgery but this did not influence the nomogram values.

Reflux resolved in 1,257 (51%) of the patients within 1.95 years of diagnosis. Surgery was necessary within 2.3 years of diagnosis because of breakthrough urinary infections, reflux scarring, nonresolution of reflux or parental preference. Variables associated with earlier time to resolution included male gender, unilateral reflux in girls, a single renal moiety, age less than 1 year, lower reflux grades and reflux diagnosed because of a sibling evaluation or history of prenatal hydronephrosis. Overall, unilateral reflux resolved faster in all patients than did bilateral reflux in female patients. The authors compare the differences in their nomogram with the 1997 reflux guideline statement. They also address limitations of their study particularly its retrospective nature and reliance on a computational model to address possible combinations of clinical variables. Ultimately, they provide a yearly nomogram for spontaneous resolution of reflux within 5 years of diagnosis.

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Cystatin-C and Outcome of Prenatal Infravesical Obstruction 

Cystatin-C, a proteinase inhibitor, is constantly secreted by cells and because of its low molecular weight it is freely filtered from the glomerulus. Cystatin-C is under investigation to determine if it is more effective in assessing renal function than serum creatinine. It may be beneficial for assessing in utero function in that it does not cross the placental barrier as does creatinine. Acar et al (page 1542) from Istanbul performed a pilot assessment of Cystatin-C obtained from fetal bladder aspiration and amniocentesis of 14 male fetuses with presumed infravesical obstruction based on association with bilateral hydronephrosis, distended thickened bladder wall, keyhole sign and oligohydramnios. They compared these fetuses to a control group of male fetuses undergoing amniocentesis for nonobstructive reasons. A total of 3 bladder punctures were performed 48 hours apart in each obstructive case. Following the third urine sample Cystatin-C was consistently higher than the prior samples in all fetuses, with the level in the amniotic fluid of the obstructed group being statistically higher than that of the control group. Identification of fetal obstructive uropathy is becoming increasingly frequent. However, determining survival outcome remains an inexact science based on the assessment of multiple factors with variable reliability. Cystatin-C may become an appropriate parameter to add to the assessment of outcome, since its presence in the amniotic fluid could limit the need for direct fetal bladder aspiration.

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Efficacy and Safety of Oxybutynin in Children With Neurogenic Detrusor Overactivity 

Oxybutynin is the most common antimuscarinic therapy used in children with neurogenic bladder dysfunction. Alternatives to oral therapy have been investigated to improve patient compliance and decrease secondary effects. In adults transdermal delivery has been shown to be as effective as oral therapy in efficacy and safety, and provides a lower plasmic concentration of N-desethyloxybutynin (DEO). Adverse effects of oxybutynin due to the active metabolite of DEO have been reported. Cartwright et al (page 1548) performed a multi-institutional study to evaluate the efficacy of transdermal delivery of oxybutynin to children with neurogenic detrusor overactivity who had previously taken either oral or transdermal oxybutynin but had no prior operative intervention, anatomical urinary tract abnormalities or skin disorders. Oxybutynin was delivered transdermally to 41 patients and orally to 16. Efficacy was evaluated by assessing the mean catheterized urine volume which increased 30 ml and 52 ml from baseline in the transdermal and oral groups, respectively. Both treatment groups demonstrated improvement in urodynamic parameters including maximal cystometric bladder capacity and a decrease in involuntary detrusor contractions. Pharmacokinetics of the plasma revealed a considerably lower level of DEO in the transdermal group compared to the oral therapy group. However, sparse sampling and timing issues prevented statistical comparison.

Seven patients in the transdermal therapy experienced 12 treatment related adverse events, 9 of which were related to site application. The only drug related adverse event in the oral therapy group was vasodilatation in 1 patient. The authors clearly note the difficulty they had with recruitment and enrollment, and how this impacted the ability to compare the efficacy of transdermal to the oral therapy. However, their results support a transdermal approach as alternative therapy to oral dosing in a child who is intolerable to a pill or suspension. In addition, the transdermal approach may provide less exposure to the anticholinergic effects of DEO.

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Pediatric Urology and the Internet 

“I saw on the internet …” is the start of a clinic conversation that is occurring with increasing frequency and often recounts information unrelated to the condition of the child. We have to accept that our patients and their families are exploring the internet for information regarding cause, evaluation and treatment, which has resulted in concern for the legitimacy of information found randomly on the web. Routh et al (page 1569) from Boston, Massachusetts selected 5 common pediatric urological conditions and compared them to 5 uncommon conditions. They used standard search terms and Google™ as the search engine. Common and uncommon sites provided high quality information but the majority of sites were not recognized by any accrediting body for medical information. The reading level required to master understanding of these sites was also high. There was no practical difference in the information between common and uncommon topics other than the fact that the diagnosis and natural history of common topics were better represented. It was interesting to note that the last updates were performed 1.8 years for common topics and 2.5 years for uncommon topics. This study provides useful insight when creating your own web site in that it is prudent to have your information succinct and directed to a grade level that can be easily understood by the lay public. In addition, maintaining your site with updates as needed is beneficial.