McSherry E, Sebastian A, Morris R C
J Clin Invest. 1972 Mar;51(3):499-514. doi: 10.1172/jci106838.
In four infants with renal tubular acidosis (RTA), including three with apparently classic RTA and one with Fanconi syndrome (FS), the physiologic character of the renal acidification defect was investigated. In two of the infants with apparently classic RTA, the acidification defect was physiologically separable from that described in both adult patients and children with classic RTA (type 1 RTA) in the following ways. (a) The fractional excretion of filtered bicarbonate (C(HCO3)/C(ln)) was not trivial but substantial (6-9%), as well as relatively fixed, over a broad range of plasma bicarbonate concentrations (15-26 mmoles/liter). (b) This value of C(HCO3)/C(ln), combined with a normal or near normal glomerular filtration rate, translated to renal bicarbonate wasting (RBW). (c) RBW at normal plasma bicarbonate concentrations was the major cause of acidosis, and its magnitude was the major determinant of corrective alkali therapy (5-9 mEq/kg per day), just as in the patient with FS, who was found to have type 2 ("proximal") RTA. (d) Persistence of RBW at substantially reduced plasma bicarbonate concentrations, which did not occur in FS, accounted for the spontaneous occurrence of severe acidosis and its rapid recurrence after reduction in alkali therapy. (e) During severe acidosis the urinary pH was >7, a finding reported frequently in infants with apparently classic RTA and "alkali-resistant" acidosis but rarely in adult patients with classic RTA. Continued supplements of potassium were required to maintain normokalemia during sustained correction of acidosis with alkali therapy. Yet, in at least two of the three infants with apparently classic RTA, but in distinction from the patient with FS and other patients with type 2 RTA, fractional excretion of filtered potassium decreased when plasma bicarbonate was experimentally increased to normal values. In one of the two infants with apparently classic RTA and RBW, C(HCO3)/C(ln) and the therapeutic alkali requirement decreased concomitantly and progressively over 2 yr, but RBW continued. Renal tubular acidosis has persisted in all four patients for at least 3 yr, and in three for 4 years.
对4例肾小管酸中毒（RTA）患儿进行了研究，其中3例表现为典型RTA，1例患有范科尼综合征（FS），探讨了其肾酸化缺陷的生理特征。在2例表现为典型RTA的患儿中，其酸化缺陷在生理上与成年患者及典型RTA（1型RTA）患儿不同，具体如下：（a）在较宽的血浆碳酸氢盐浓度范围（15 - 26毫摩尔/升）内，滤过碳酸氢盐的分数排泄率（C(HCO3)/C(ln)）并非微不足道，而是相当可观（6 - 9%），且相对固定。（b）C(HCO3)/C(ln)这一数值，结合正常或接近正常的肾小球滤过率，导致了肾碳酸氢盐丢失（RBW）。（c）正常血浆碳酸氢盐浓度时的RBW是酸中毒的主要原因，其程度是纠正性碱治疗（5 - 9毫当量/千克/天）的主要决定因素，这与患有2型（“近端”）RTA的FS患儿情况相同。（d）血浆碳酸氢盐浓度大幅降低时RBW仍持续存在，这在FS患儿中未出现，这导致了严重酸中毒的自发发生及其在碱治疗减少后迅速复发。（e）在严重酸中毒期间，尿pH值＞7，这一发现常见于表现为典型RTA和“耐碱”酸中毒的婴儿，但在成年典型RTA患者中很少见。在用碱治疗持续纠正酸中毒期间，需要持续补充钾以维持血钾正常。然而，在3例表现为典型RTA的患儿中，至少有2例与FS患儿及其他2型RTA患者不同，当血浆碳酸氢盐通过实验性增加至正常水平时，滤过钾的分数排泄率降低。在2例表现为典型RTA且存在RBW的患儿中，有1例的C(HCO3)/C(ln)和治疗所需碱量在2年中同时逐渐降低，但RBW仍持续存在。所有4例患者的肾小管酸中毒至少已持续3年，3例已持续4年。
