Incidence and clinical features of renal tubular acidosis-1 in urolithiasis.

To elucidate the frequency and clinical picture of renal tubular acidosis-1 (RTA-1) in nephrolithiasis, the acid-loading test was performed in 474 patients with calcium-containing stones. RTA-1 was detected in a total of 11 patients (6 men and 5 women, 2.3%). The incidence of RTA-1 in female patients tended to be higher than in male patients (3.2 vs. 1.9%). One male patient had the complete form, the others had incomplete form. There was a tendency that RTA-1 patients were younger than non-RTA-1 patients in men, and the former were older than the latter in women. The percentages of positive family history and positive past history were 27 and 45%, respectively. Stones were single in 7 cases and multiple in 4 cases. They were unilateral in 10 cases, and bilateral in 1 case. Hypercalciuria was detected in 2 of the 11 cases, hyperuricosuria was present in none of the 11 cases, and hyperoxaluria in 2 of 8 cases examined. Stones were composed of calcium oxalate in 2 cases, calcium phosphate in 2, and calcium oxalate mixed with calcium phosphate in 3.