CHEMODISSOLUTION OF URINARY URIC-ACID STONES BY ALKALI THERAPY

Experience with chemodissolution of uric acid stones in 30 patients is presented. Chemodissolution was achieved either with infusion of 0.16 M i.v. lactate or oral sodium bicarbonate, in addition to liberal fluid intake and allopurinol wherever indicated. In some cases direct chemodissolution by in situ irrigation with sodium bicarbonate solution was done after an initial percutaneous nephrostomy. Seven patients presented with acute obstructive anuria. In this group, 5 of them had bilateral obstructive calculi, while 2 had unilateral obstruction in a solitary kidney. The latter 2 had complete recovery following intravenous lactate therapy. Of the 5 presenting with bilateral obstruction, 2 patients had complete response to chemodissolution, whereas the remaining 3 had only a partial response requiring surgery for ultimate salvage. In this group I, 6 patients are doing well with a normal serum creatinine at 3 months to 4 years follow-up, while 1 patient has a serum creatinine, stabilised at 3.2 mg%. In the second group, 23 patients presented with non-obstructing urinary stones. Flank pain was the commonest complaint and a concomitant history of gout was present in 6 patients. Hyperuricaemia was detected in 12 and hyperuricosuria in 19. All cases were managed by high fluid intake and oral sodium bicarbonate, with self-monitoring of urine pH, which was kept between 6.5 and 7.0. Allopurinol was administered in cases having hyperuricaemia and/or hyperuricosuria. Systemic alkali therapy in the form of intravenous molar lactate or sodium bicarbonate is effective and safe both in obstructive anuria and non-obstructive urinary uric acid stones.