Extracorporeal renal lithotripsy:: Evolution of residual lithiasis treated with thiazides

Objectives. To analyze the evolution of residual lithiasis after renal extracorporeal shock wave lithotripsy (ESWL) and to show the prolonged efficacy of thiazides in the treatment of residual lithiasis in patients with calcium lithiasis. Methods. We performed a longitudinal, analytical, 36-month study in 100 patients with residual calcium lithiasis after ESWL randomly distributed into two groups: 50 patients treated with placebo (controls, group 1) and 50 treated with hydrochlorothiazide, 50 mg/24 hr (group 2). All patients in both groups underwent imaging studies (simple radiography of the urinary tract and renal ultrasonography) and a metabolic urinary study. Results. The percentage of global expulsion of lithiasis during the follow-up period was significantly greater (chi-square exponent = 19.938, P = 0.001) in the patients treated with thiazides (72%) than in the control group (36%), although a large number of patients in this group underwent new ESWL sessions. During the follow-up period, we performed ESWL on 42% of the patients in group 1 and 18% of group 2, a statistically significant difference (chi-square exponent = 6.881, P = 0.032). Conclusions. The results of our study have shown that residual lithiasis progresses in 58% of patients undergoing observation, and new ESWL sessions will be necessary in 42%. We observed a significant relationship between the presence of a urinary lithogenic pattern and the progression of the residual lithiasis. The administration of thiazides stabilizes or reduces the growth of residual lithiasis and favors its spontaneous elimination, thus reducing the need for new sessions of ESWL. This effect of thiazides is highly significant in patients presenting with hypercalciuria.