title: Urinary citrate excretion in idiopathic nephrolithiasis.
abstract: OBJECTIVE
  To determine urinary citrate excretion in children with nephrolithiasis and normal controls.
  
  
  METHODS
  Prospective.
  
  
  METHODS
  Tertiary care center in New Delhi.
  
  
  METHODS
  This study was done on 50 children, below the age of 12 years, with idiopathic urinary calculi and 150 age and weight matched controls. The children were divided into 3 groups: Group 1 (1-4 years), Group 2 (5-8 years) and Group 3 (9-12 years). Urinary citrate was estimated in a 24-hour urine sample using colorimetric method. The stones removed from these children were also analysed.
  
  
  RESULTS
  There was a preponderance of urinary stones in males; the highest incidence being in Group 1. Excretion of citrate in 24-hour urine sample was significantly lower in patients compared to controls, for males in all age groups and for females in Group 3. However, there was no statistically significant difference in the urinary citrate value between males and females in a given age group for either controls or patients. The urinary citrate excretion increased with age in patients and controls, but the levels in patients were lower. Depending upon the constituents, four types of stones were identified, calcium phosphate, calcium oxalate, uric acid and magnesium ammonium phosphate. Nine stones had at least more than one major constituent. Hypocitraturia was detected in 43 percent cases. The incidence was 76 percent for calcium phosphate, 87 percent for calcium oxalate, 40 percent for uric acid stones and 50 percent for magnesium ammonium phosphate.
  
  
  CONCLUSIONS
  This study shows that low urinary citrate is associated with urinary stones in children, especially in endemic areas, in the absence of obvious etiological factors. Urinary citrate excretion should be determined in all children with nephrolithiasis.
mesh_terms: D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D019343:Citric Acid / Q000652:urine*; D005260:Female; D006801:Humans; D007223:Infant; D007669:Kidney Calculi / Q000737:chemistry / Q000652:urine*; D008297:Male; D011446:Prospective Studies
chemical_list: D019343:Citric Acid