Importancia del déficit de inhibidores de la cristalización en la etiopatogenia de la urolitiasis / Importance of crystallization inhibitors deficit in the etiopathogenic of urolithiasis

RESUMO

Background: five percent of consultations at the emergency room of Catholic University Hospital are due to nephrolithiasis. The causes of this high frequency remain unknown. Aim: to know the main metabolic and anatomic factors involved in the genesis of nephrolithiasis. Patients and methods: 41 patients (31 male) were studied presenting with a renal colic were studied as soon as the acute episode subsided and without diet modifications. Fasting blood calcium and creatinine and 24 h urine calcium, uric acid, citrate, magnesium and pH were measured and an intravenous pyelogram was performed. 21 subjects without a history of nephrolithiasis were used as controls. Results: Patients with nephrolithiasis did not differ from controls in urinary calcium (159 ñ 67 and 172 ñ 67 mg/24 h respectively), uricosuria (417 ñ 171 and 431 ñ 121 mg/24 h respectively) or urinary magnesium (55 ñ 19 and 62 ñ 21 mg/24 h respectively, whereas urinary citrate was lower (219 ñ 172 vs 319 ñ 179 mg/24 h in controls p <0.05). All patients had a normal renal functions, urinary acidification and intravenous pyelogram. Seven percent of patients with nephrolithiasis had hypercalciuria, 2.4 percent had hyperuricosuria, 68.3 percent had a low urinary citrate and 44.4 percent had low urinary magnesium. Conclusions: in this sample, there is a strong association of nephrolithiasis with low levels of crystallization inhibitors in special with urinary citrate, a crystallization inhibitor