Tessitore N, Ortalda V, Fabris A, D'Angelo A, Rugiu C, Oldrizzi L, Lupo A, Valvo E, Gammaro L, Loschiavo C
Nephron. 1985;41(4):325-32. doi: 10.1159/000183609.
The frequency of renal tubular acidosis was evaluated in 28 adult patients with recurrent calcium nephrolithiasis (19 with 'renal' hypercalciuria, 9 with normocalciuria and no metabolic abnormality) and no evidence of obstruction or infection of the urinary tract. Eight patients with hypercalciuria (42%) had a defective renal reabsorption of bicarbonate, based on a fractional excretion of bicarbonate higher than 7% and a TmHCO3/GFR lower than 2.2 mEq/dl; 2 of them had an associated distal defect of acidification, as judged by a U-B pCO2 lower than 18 mm Hg in maximally alkaline urine. One patient with hypercalciuria had distal tubular acidosis, based on a urine pH higher than 5.3 during acidosis. Only 1 patient with normocalciuria had associated proximal and distal acidification defects. The remaining 8 patients displayed a normal renal acidifying capacity. The bicarbonate wastage was independent of serum PTH levels, vitamin D status and hypercalciuria and was associated with a defective tubular reabsorption of phosphate, increased random urinary pH and more active nephrolithiasis, with a prevalence of mixed calcium oxalate and phosphate stones. Our study shows a high incidence of defective tubular reabsorption of bicarbonate in patients with calcium nephrolithiasis and 'renal' hypercalciuria and suggests that the proximal acidification defect plays a pathogenetic role in promoting calcium nephrolithiasis.
对28例复发性钙肾结石成年患者（19例为“肾性”高钙尿症，9例为正常钙尿症且无代谢异常）进行肾小管酸中毒频率评估，这些患者无尿路梗阻或感染证据。8例高钙尿症患者（42%）存在碳酸氢盐肾重吸收缺陷，依据碳酸氢盐排泄分数高于7%且TmHCO3/GFR低于2.2 mEq/dl判断；其中2例伴有远端酸化缺陷，依据最大碱性尿中U-B pCO2低于18 mmHg判断。1例高钙尿症患者存在远端肾小管酸中毒，依据酸中毒期间尿pH高于5.3判断。仅1例正常钙尿症患者伴有近端和远端酸化缺陷。其余8例患者肾酸化能力正常。碳酸氢盐浪费与血清甲状旁腺激素水平、维生素D状态和高钙尿症无关，且与磷酸盐肾小管重吸收缺陷、随机尿pH升高及更活跃的肾结石形成相关，草酸钙和磷酸盐混合结石患病率较高。我们的研究表明，钙肾结石和“肾性”高钙尿症患者中碳酸氢盐肾小管重吸收缺陷发生率较高，提示近端酸化缺陷在促进钙肾结石形成中起致病作用。
