title: Hypercalciuria and pediatric stone recurrences with and without structural abnormalities.
abstract: OBJECTIVE
  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.
  
  
  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.
authors.affiliation: Department of Urology, LeBonheur Children's Medical Center and University of Tennessee, Memphis, Memphis, Tennessee, USA.
authors.forename: H N
authors.initials: HN
authors.lastname: Noe
mesh_terms: D002118:Calcium / Q000652:urine*; D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D012008:Recurrence; D012189:Retrospective Studies; D012307:Risk Factors; D014545:Urinary Calculi / Q000453:epidemiology / Q000652:urine*
chemical_list: D002118:Calcium