Nephrolithiasis in medullary sponge kidney.

Seventy-one patients with documented Medullary Sponge Kidney (MSK) and nephrolithiasis underwent complete metabolic evaluation. These patients constituted 7.3% of our calcium stone-forming population Metabolic anomalies (hypercalciuria, hyperoxaluria, hypocitraturia and hyperuricosuria) were observed in 82% of patients. No patient was hypercalcemic and none had hyperparathyroidism. Thus the patients with medullary sponge kidney and renal stones had the same spectrum of metabolic anomalies as the overall population of idiopathic stone formers. Although these patients may have anatomic anomalies which determine stasis of urine and infection causing stone formation, they should be evaluated and treated appropiately for any metabolic defect.