The optimal dose of potassium citrate in the treatment of children with distal renal tubular acidosis.
BACKGROUND
Distal renal tubular acidosis (RTA) is a common cause of intractable calcium nephrolithiasis. In adults, the use of potassium citrate (PC) in distal RTA effectively decreases metabolic acidosis and the risk of calcium oxalate stone but it cannot decrease the risk of calcium phosphate stone. However, there is no report for the optimal dose of PC and the risk of calcium stone in distal RTA in children.


OBJECTIVE
To evaluate the optimal dose of PC that minimizes the risk of calcium nephrolithiasis in children with distal RTA.


METHODS
Prospective study


METHODS
Children who have distal RTA and were followed-up for 4 months. Patients were studied in a control phase, 1 month of PC 2 mEq/kg/day, 2 months of PC 3 mEq/kg/day and 1 month of PC 4 mEq/kg/day. The urine specimens of 41 normal children were measured for the reference value of the parameters determining the risk of calcium stone.


RESULTS
Eight children (mean age of 10 +/- 3.7 years, female : male = 6: 2) with distal RTA were studied during the control phase and after receiving PC 2 mEq/kg/day for I month. Treatment with PC 2 mEq/kg/day was not able to normalize serum bicarbonate and caused no significant change in the urine citrate/creatinine ratio, and activity production of calcium phosphate stone but it caused a significant decrease in the urine calcium/citrate ratio. Although PC 3 mEq/kg/day for I month normalized plasma bicarbonate, only this dose given for 2 months caused a significant increase in the urine citrate/creatinine ratio and urine calcium/ citrate ratio to values that were not different from normal children, while the activity production of calcium phosphate stone did not decrease to normal level. The effect of PC 4 mEq/kg/day was similar to that of 3 mEq/kg/day.


CONCLUSIONS
Potassium citrate 3 mEq/kg/day for 2 months effectively normalized serum bicarbonate and decreased the risk of calcium oxalate stone but this treatment was theoretically unable to reduce the risk of calcium phosphate stone in children with distal RTA.
Tapaneya-Olarn
Wiwat
W
Department of Pediatrics, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok 10400, Thailand.
Khositseth
Sukkasem
S
Tapaneya-Olarn
Chaleomsri
C
Teerakarnjana
Narumon
N
Chaichanajarernkul
Upsorn
U
Stitchantrakul
Wasana
W
Petchthong
Thanom
T
D000141:Acidosis, Renal Tubular / Q000188:drug therapy*; D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D004232:Diuretics / Q000008:administration & dosage* / Q000627:therapeutic use*; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D008297:Male; D019357:Potassium Citrate / Q000008:administration & dosage* / Q000627:therapeutic use*
D004232:Diuretics; D019357:Potassium Citrate