Metabolic evaluation of urolithiasis and obesity in a midwestern pediatric population.

PURPOSE: The incidence of urolithiasis has been proved to be increasing in the adult population, and evidence to date suggests that the same holds true for the pediatric population. While adult urolithiasis is clearly linked to obesity, studies of pediatric patients have been less conclusive. We hypothesized that a population of otherwise healthy children with stones would have an increased body mass index compared to a control population, and that obese pediatric stone formers would have results on metabolic assessment that are distinct from nonobese stone formers. MATERIALS AND METHODS: We retrospectively reviewed the charts of all patients 10 to 17 years old with upper tract urolithiasis without comorbidities treated between 2006 and 2011. Mean body mass index of our population was compared to state data, and 24-hour urine collection results were compared between obese and nonobese patients with stones. RESULTS: The obesity rate in 117 patients with urolithiasis did not differ significantly from the obesity rate derived from the 2007 National Survey of Children's Health (observed/expected ratio 1.11, 95% CI 0.54-1.95). Using t-test and chi-square comparisons, overall 24-hour urine collection data did not show statistically significant differences. CONCLUSIONS: Our results do not confirm obesity as a risk factor for pediatric urolithiasis in otherwise healthy patients. We also found no substantial metabolic differences between healthy nonobese stone formers and obese patients. While the pediatric literature is mixed, our study supports the majority of published series that have failed to establish a link between pediatric urolithiasis and obesity.

Urolithiasis in patients on high dose felbamate.

PURPOSE: We report 4 cases of felbamate urolithiasis. We identified only 1 prior case report of a felbamate stone. Felbamate is an antiepileptic drug used to treat refractory seizures and has minor side effects when given in recommended doses. We analyzed the characteristics, evaluation, treatment and outcomes in this challenging group of patients. MATERIALS AND METHODS: Following institutional review board approval, we conducted a retrospective chart review of all patients who presented with a diagnosis of urolithiasis, were on felbamate and had stone analysis consistent with a felbamate origin. RESULTS: All 4 patients had refractory seizures and 3 had severe developmental delay. Presentation ranged from an incidental finding to gross hematuria to agitation and pain. Stones were not visible on plain x-ray except in 1 case involving mixed stone composition. Decrease or cessation of the drug has not been feasible in 2 patients, and 3 patients have had recurrent stones. Initial stone analysis did not correctly identify the stone composition as felbamate in 2 cases, suggesting that the origin of these stones may not always be recognized. CONCLUSIONS: We report the occurrence of felbamate stones in a series of patients on high dose felbamate therapy. Accurate diagnosis is made more difficult by the clinical complexity of the patient population (including severe developmental delay), the radiolucent nature of the stones and the possibility of inaccurate analysis of stone composition.

Advanced transitional cell carcinoma of the bladder in a 16-year-old girl with Hinman syndrome.

The present report describes a 16-year-old girl with a history of Hinman syndrome who was found to have invasive transitional cell carcinoma of the bladder. Bladder cancer is rare in children. Typically, the tumors are of low grade and stage. We present the first case of a teenage girl diagnosed with Hinman syndrome who developed an invasive bladder transitional cell carcinoma. The patient with a neurogenic bladder who has undergone bladder augmentation is at increased risk for bladder cancer. This risk may now have to be extended out to the non-neurogenic neurogenic bladder population if further cases are identified.