Urinary Citrate excretion in patients with Urolithiasis

Abstract

Objective: To determine urinary citrate excretion in patients with urolithiasis and normal controls. A prospective study was coducted at ACPM Medical College, Dhule. Methods: This study was carried out on, 100 normal individuals and 100 kidney stone patients (76males and 24 females) with idiopathic urinary calculi and 100 ages and weight matched controls. The patients were divided into 3 groups: Group 1 (15-30 years), Group 2 (31-45 years) and Group 3 (46-60 years). Urinary citrate was estimated in a 24-hour urine sample using colorimetric method. The stones removed from these Patients were also analysed. Results: There was a preponderance of urinary stones in males; the highest incidence being in Group 2. 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. 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. Forty six stones had at least more than one major constituent. Hypocitraturia was detected in 93% cases. The incidence was 72% for calcium phosphate, 89% for calcium oxalate, 36% for uric acid stones and 25% for magnesium ammonium phosphate. Conclusion: This study shows that low urinary citrate is associated with urinary stones in patients, especially in endemic areas, in the absence of obvious etiological factors. Urinary citrate excretion should be determined in all patients with urolithiasis.