Hypercalciuria and pediatric stone recurrences with and without structural abnormalities

Purpose: This study defines to what extent hypercalciuria represents a risk factor for recurrent calcium oxalate or nonstruvite stones. Long-term followup of children with hypercalciuria after an initial stone episode allowed us to determine the rate of stone recurrence. Materials and Methods: A total of 44 pediatric patients with stones were diagnosed with hypercalciuria, including 7 with structural abnormalities and 37 with normal anatomy. Of these patients 27 had adequate long-term followup. Results: There were 9 stone recurrences in the 27 patients who were evaluated long term for an overall recurrence rate of 33%. Recurrences developed 3 to 15 years after the initial episode (average time to recurrence 7.2 years), and none of the patients with structural abnormalities had hydronephrosis at recurrence. Of the 9 patients with stone recurrences 3 were female and 6 were male, and 4 had multiple stone recurrence episodes. Of these 9 cases of recurrent stones 8 had a positive family history for stone disease in a first degree relative, whereas only 8 of 18 cases without stone recurrence had a positive family history (p = 0.04). Conclusions: Hypercalciuria is a risk factor for recurrence in the pediatric patient with stones with and without structural abnormalities. New stones can occur several years after the initial episode and can extend through postpuberty.