The role of hypercalciuria in a subgroup of dysfunctional voiding syndromes of childhood

Purpose: Idiopathic hypercalciuria is believed to be the cause of a variety of urinary tract complaints in clinical pediatrics, including urinary freq uency, urgency, and/or dysuria, often associated with gross or microscopic hematuria. In children noncalculous manifestations of idiopathic hypercalci uria are reportedly more common than urolithiasis. We determine the use of the calcium-to-creatinine ratio for the evaluation of different subsets of functional voiding disorders. Materials and Methods: We retrospectively evaluated 288 patients with funct ional voiding disorders during the last 8 years. Patients presenting with i solated urinary tract infection were not included in the study. A thorough history with emphasis on voiding patterns was elicited and a routine urinal ysis was performed in all patients. Patients were divided into 5 groups of 22 with total gross hematuria and dysfunctional voiding pattern, 102 with m icrohematuria and dysfunctional voiding pattern, 66 with isolated childhood daytime frequency, 45 with the isolated dysuria syndrome and 53 with combi ned childhood frequency-urgency-dysuria syndrome. The season at presentatio n was noted to determine a seasonal pattern. In 149 patients urine was eval uated for a spot calcium-to-creatinine ratio. Results: Mean age of the 95 (33%) males and 193 (67%) females was 6.1 years (range 2 to 14) and mean duration of symptoms was 10 months (1 week to 10 years). The incidence of idiopathic hypercalciuria was 28% in cases with gr oss hematuria and dysfunctional voiding, 30% with microscopic hematuria and dysfunctional voiding, 21% with pure childhood daytime frequency, 22% with pure dysuria, and 28% with frequency, urgency and dysuria. The patients we re treated predominantly with behavioral therapy, correction of faulty void ing habits, anticholinergics and minor diet modification in some. Mean foll owup of 6.5 months (range 1 month to 10 years) was available for 153 patien ts (53%). Resolution of symptoms along with marked improvement in voiding h abits was noted in 136 (89%) patients, moderate improvement in 10 (6.5%) an d persistent symptoms with minimal improvement in 7 (4.5%). Treatment with thiazides was used in only 6 (2%) patients who had intractable symptoms and a markedly elevated urine calcium-to-creatinine ratio of whom 5 responded favorably. Conclusions: Idiopathic hypercalciuria may have a significant role in cases of functional voiding disorders. It affects the different subsets of voidi ng disorders with remarkable consistency but the exact mechanism remains un known. Although a significant number of patients with voiding dysfunction h ave an elevated calcium-to-creatinine ratio, the majority respond to standa rd behavioral therapy and pharmacotherapy in the form of anticholinergics, and treatment directed toward hypercalciuria is not required in most cases.