title: Changing stone composition profile of children with nephrolithiasis.
abstract: OBJECTIVE
  To determine if this trend toward calcium phosphate stone formation exists in children.
  
  
  METHODS
  This is a retrospective study of medical records of 179 children managed at our medical center from 1992-2010 for whom stone analysis and other pertinent laboratory data were available. A comparison of patients managed from 1992-2000 (P1) and 2001-2010 (P2) was undertaken. Statistical analysis included nonparametric tests.
  
  
  RESULTS
  There were no significant differences in the mean age of the 2 cohorts. During both periods, boys comprised a significantly higher proportion during the first decade of life, whereas girls comprised a significantly higher proportion during the second decade. A higher percentage of patients had calcium oxalate (CaOx) stones in P1 compared to P2 (60% vs 47%, P = .0019). There was a significant increase in the percentage of patients having calcium phosphate stones in P2 compared to P1 (27% vs 18.5%, P = .008). Twenty-seven patients had recurrent stones. A comparison of the compositions of the first and last stones of patients within this group demonstrated an increasing proportion of brushite stones (3.7% vs 11.1%, P = .04). Twenty-four hour urine testing results were similar for those with CaOx and calcium phosphate stones.
  
  
  CONCLUSIONS
  An increasing proportion of children have calcium phosphate calculi. Brushite stones are more prevalent in children with recurrent stone events. The impetus of these shifts is not readily apparent.
authors.affiliation: Department of Urology, Wake Forest Baptist Medical Center, Winston-Salem, NC, USA.
authors.forename: Kyle D
authors.initials: KD
authors.lastname: Wood
authors.forename: Irina S
authors.initials: IS
authors.lastname: Stanasel
authors.forename: David S
authors.initials: DS
authors.lastname: Koslov
authors.forename: Patrick W
authors.initials: PW
authors.lastname: Mufarrij
authors.forename: Gordon A
authors.initials: GA
authors.lastname: McLorie
authors.forename: Dean G
authors.initials: DG
authors.lastname: Assimos
mesh_terms: D000293:Adolescent; D000367:Age Factors; D002129:Calcium Oxalate / Q000032:analysis*; D002130:Calcium Phosphates / Q000032:analysis*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007669:Kidney Calculi / Q000737:chemistry*; D008297:Male; D012008:Recurrence; D012189:Retrospective Studies; D012737:Sex Factors; D018709:Statistics, Nonparametric
chemical_list: D002130:Calcium Phosphates; D002129:Calcium Oxalate; C020243:calcium phosphate; C494366:calcium phosphate, dibasic, dihydrate