Introduction: Bladder stones constitute approximately 5% of all urinary tract stones. In recent years, improved access to health care and improved nutritional status in children has led to a reduction of stone cases in many Asian countries. In the case of bladder stone in children, the term giant bladder stone which is based only on the stone burden cannot be applied, considering the capacity of a child's bladder that continues to increase with age. Objective: This current study aims to propose a new term related to giant bladder stones in pediatric patient populations concerning the stone burden, bladder capacity, and renal impairment related to the bladder stone. Methods: Thirty-four children with bladder stones in our center between January 2014 to August 2019 were admitted to the study. Data regarding patient's age, clinical symptoms, dietary history, socioeconomic status, laboratory investigations include complete blood examination, urinalysis and urine culture, presence of hydronephrosis, stone size, nutritional status, and type of procedure were collected. Estimated stone volume (ESV) was measured using Ackermann's formula, while estimated bladder capacity (EBC) was calculated using Koff formulas. Receiver operating characteristic (ROC) curve was constructed to determine the best cut-off value for determining what ESV to EBC ratio value at which a bladder stone cause hydronephrosis. Result: Hydronephrosis was noted in 12 patients. A significant difference in the mean ESV and ESV to EBC ratio was found between those two groups (p < 0.001 and 0.006 respectively). ROC curve was used to assess the accuracy of the ESV to EBC ratio as a predictor of hydronephrosis incidence with the area under the curve 0.768 (95% CI 0.624 to 0.949). Cut-off value of this ESV to EBC ratio is 0.0286 with a sensitivity 94.40%, specificity 62.50%, positive predictive value 73.91%, and negative predictive value 90.90%. Conclusion: We propose to use the term giant in pediatric cases using the EBV to EBC ratio above 0.028. Highlights

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Introduction: Mirabegron, a b3-adrenoceptor (b3-AR) agonist approved for the treatment of overactive bladder (OAB) symptoms in the adult population, is the first of a new class of compounds with a different mechanism of action. Mirabegron act during the bladder storage phase by relaxing the detrusor muscle thus increase bladder capacity without any significant impact on voiding. Although antimuscarinic agents are commonly used for daytime incontinence associated with overactive bladder and also for patient with congenital cause such as spina bifida, mirabegron could be an effective treatment option in children with neurogenic bladder, as shown in adult populations. In this systematic review, we aimed to evaluate the available literature regarding efficacy and safety of mirabegron in pediatric population. Method: This systematic review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. Result: The symptoms analyzed were frequency, urgency, nocturnal enuresis (NE) and daytime incontinence (DI). 37 (53%) out of 70 children were still receiving treatment at 6 months; 30 received mirabegron monotherapy, and 7 received combination therapy with anticholinergic (Solifenacin n = 4, Desmopressin n = 2, both n = 1). After six months, blood pressure monitoring and ECGs were normal in all patients. For patients on monotherapy, 6 of 17 (35%) had improvement in NE, 11 of 19 (58%) in DI, 12 of 20 (60%) in frequency, and 8 of 21 (38%) in urgency symptoms. For patients receiving combination therapy, 2 of 6 (33%) had improvement in NE, 2 of 4 in DI (50%), 2 of 4 (50%) in frequency, and 4 of 6 (67%) had improvement in urgency. Conclusion: The CV safety of mirabegron, the only clinically available β3-adrenoceptor agonist, appears to be good and comparable with that of antimuscarinic agents, the current first-line therapy for OAB. However, Further long-term data are desirable especially in patients with poorly controlled hypertension, arrhythmia, or cardiac heart failure. Highlights