title: Crystal-associated nephropathy in patients with brushite nephrolithiasis.
abstract: BACKGROUND
  We have biopsied the renal cortex and papillae of patients who form brushite renal stones asking if this unusual stone type is associated with specific tissue changes. We contrasted these with biopsies of 15 calcium oxalate stone formers, three stone formers with intestinal bypass, and four normal subjects.
  
  
  METHODS
  We studied all ten brushite stone formers treated with percutaneous nephrolithotomy (PNL) during the past 3 years using digital video imaging of renal papillae, and obtained cortical and papillary biopsies. Biopsies were analyzed by light and electron microscopy, microinfrared spectroscopy, and electron diffraction.
  
  
  RESULTS
  Apatite crystals plugged scattered terminal collecting ducts whose cells were injured or dead, and surrounding interstitium inflamed and fibrotic. White papillary deposits of interstitial apatite particles, so called Randall's plaque, were also present. Glomerular changes and cortical tubular atrophy and interstitial fibrosis were moderate to severe.
  
  
  CONCLUSIONS
  Brushite stone formers combine the interstitial plaque of calcium oxalate stone formers with the collecting duct apatite plugs found in stone formers with intestinal bypass. Collecting duct injury and interstitial fibrosis are severe. Prominent cortical fibrosis, tubule atrophy, and glomerular pathology seem secondary to the collecting duct plugging. We believe crystallization obstructs and destroys terminal collecting duct segments thereby damaging nephrons, perhaps via intranephronal obstruction, and producing a hitherto unrecognized renal disease.
authors.affiliation: Department of Anatomy and Cell Biology, Indiana University School of Medicine, Indianapolis, Indiana 46220, USA. evan@anatomy.iupui.edu
authors.forename: Andrew P
authors.initials: AP
authors.lastname: Evan
authors.forename: James E
authors.initials: JE
authors.lastname: Lingeman
authors.forename: Fredric L
authors.initials: FL
authors.lastname: Coe
authors.forename: Youzhi
authors.initials: Y
authors.lastname: Shao
authors.forename: Joan H
authors.initials: JH
authors.lastname: Parks
authors.forename: Sharon B
authors.initials: SB
authors.lastname: Bledsoe
authors.forename: Carrie L
authors.initials: CL
authors.lastname: Phillips
authors.forename: Stephen
authors.initials: S
authors.lastname: Bonsib
authors.forename: Elaine M
authors.initials: EM
authors.lastname: Worcester
authors.forename: Andre J
authors.initials: AJ
authors.lastname: Sommer
authors.forename: Sam C
authors.initials: SC
authors.lastname: Kim
authors.forename: William W
authors.initials: WW
authors.lastname: Tinmouth
authors.forename: Marc
authors.initials: M
authors.lastname: Grynpas
mesh_terms: D000293:Adolescent; D000328:Adult; D001031:Apatites / Q000378:metabolism; D002130:Calcium Phosphates / Q000378:metabolism*; D002648:Child; D003460:Crystallization; D004847:Epithelial Cells / Q000473:pathology; D005260:Female; D005355:Fibrosis; D006801:Humans; D007668:Kidney / Q000473:pathology; D007669:Kidney Calculi / Q000473:pathology*; D007674:Kidney Diseases / Q000209:etiology*; D008297:Male; D008875:Middle Aged
chemical_list: D001031:Apatites; D002130:Calcium Phosphates; C494366:calcium phosphate, dibasic, dihydrate