A STUDY OF RECURRENT STONE FORMERS WITH SPECIAL REFERENCE TO RENAL TUBULAR-ACIDOSIS

Forty-five patients with recurrent renal stone were examined for dista l renal tubular acidosis (dRTA) defects by acid challenge test (150 mg ammonium chloride/kg body weight). Their 24-h urine samples were anal ysed for creatinine, calcium, oxalic acid, inorganic phosphorus, uric acid, magnesium and citric acid. One-hour urine samples before acid lo ad and hourly samples for the 7 h following acid challenge test were c ollected and analysed for creatinine, calcium, citric acid, inorganic phosphorus, titratable acidity, and ammonium. The incidence of distal RTA defect was 22.2% in the patients examined. The major biochemical c haracteristics in RTA patients compared with patients without RTA were : (a) significantly higher urinary pH, (b) significantly lower excreti on of citric acid, (c) no significant difference in calcium excretion and (d) a tendency toward lower titratable acidity and ammonium excret ion.