Effect of potassium citrate therapy on stone recurrence and regrowth after extracorporeal shockwave lithotripsy in children

BACKGROUND AND PURPOSE: Stone disease in children may cause functional and morphologic changes in the urinary tract during longer-term follow-up. Prevention of stone recurrence will be possible only with careful metabolic evaluation and appropriate management. The possible preventive effects of potassium citrate therapy on true stone recurrence, as well as regrowth rates after shockwave lithotripsy (SWL), were evaluated in children treated for renal stones. PATIENTS AND METHODS: Following assessment of the efficacy of SWL, 96 children (72 male, 53 female aged 4 to 14 years with a mean of 6.6 years) were evaluated for the effects of potassium citrate on residual fragments as well as true new stone formation during long-term follow-up. All children had calcium-containing stones with normal renal morphology and function without any urinary-tract infection. Depending on the outcome of treatment, patients with and without residual stones were allocated independently to Group I (N = 52) and Group II (N = 44), which were matched for sex and age. Group I was given oral potassium citrate 1 mEq/kg daily for 12 months; the remaining children served as controls. Follow-up ranged from 12 to 36.6 months, with a mean of 24.4 months. Follow-up results for at least a year with respect to the stone recurrence or stone growth rates were recorded in both groups. RESULTS: Stone-free children undergoing no specific therapy had significant new stone formation compared with the group receiving potassium citrate on a regular basis (34.6% and 7.6%, respectively). Children with residual fragments receiving no specific preventive measure also showed significant new stone formation, along with enlargement of the fragments. CONCLUSION: In addition to stone removal, treatment of pediatric urolithiasis requires a thorough metabolic evaluation. Depending on the abnormalities, each patient should be advised on adequate drinking to increase the urine volume in accordance with body size. Although children with hypocitraturia may well benefit from therapeutic agents that raise the urine citrate concentration, our results did clearly show that all children bearing residual fragments should be counseled on adequate fluid intake along potassium citrate treatment to prevent stone regrowth or formation during long-term follow-up.