Chandar J, Abitbol C, Zilleruelo G, Gosalbez R, Montané B, Strauss J
Department of Pediatrics, University of Miami, Jackson Memorial Medical Center, Florida, USA.
J Urol. 1996 Feb;155(2):660-3.
Abnormalities in renal tubular function have been observed in hydronephrotic urinary tract disease, resulting in metabolic acidosis, hyperkalemia and excessive free water diuresis. The frequency of these abnormalities, particularly in our infant population, was the impetus for our study.
We studied 50 infants selected from 199 patients followed for hydronephrosis before any surgical intervention during a 5-year period. Mean patient age was 1.5 +/- 1.0 months at the time of diagnosis by ultrasound, voiding cystourethrography and a radionuclide renal scan. Lesions were classified as unilateral or bilateral and graded according to severity of renal pelvic dilatation or grade of vesicoureteral reflux.
At least 1 abnormality of tubular function was present in 29 patients (58%) of whom the predominant abnormality was renal tubular acidosis in 23 (79%, 46% of the total study group). Renal tubular acidosis was diagnosed on the basis of a serum total carbon dioxide of 19 mM./l. or less with urinary pH 5.5 or greater. The defect appeared to be distal in most cases. Other abnormalities included defects in urinary concentrating ability in 10 patients (4 with unilateral urinary tract dilatation). Distal tubular aldosterone resistance in 6 patients (3 with unilateral dilatation) was demonstrated by hyperkalemia with a low transtubular potassium gradient of 3 or less and low fractional excretion of potassium. Although common in unilateral lesions, renal tubular dysfunction became more prevalent with an increase in severity score and bilaterality.
Renal tubular dysfunction is frequent in hydronephrotic infants with unilateral or bilateral disease. Although rarely life threatening and usually self-limiting, the metabolic consequences of these abnormalities require investigation to allow for appropriate medical management.
在肾积水性泌尿系统疾病中已观察到肾小管功能异常，可导致代谢性酸中毒、高钾血症和自由水利尿过多。这些异常情况的发生率，尤其是在我们的婴儿群体中的发生率，是我们开展这项研究的动力。
我们从199例在5年期间接受肾积水随访且未进行任何手术干预的患者中选取了50例婴儿进行研究。通过超声、排尿性膀胱尿道造影和放射性核素肾扫描诊断时，患者的平均年龄为1.5±1.0个月。病变分为单侧或双侧，并根据肾盂扩张的严重程度或膀胱输尿管反流的分级进行分级。
29例患者（58%）至少存在1种肾小管功能异常，其中主要异常为肾小管酸中毒的有23例（79%，占整个研究组的46%）。肾小管酸中毒的诊断依据是血清总二氧化碳浓度为19mmol/L或更低，且尿液pH值为5.5或更高。在大多数情况下，缺陷似乎是远端性的。其他异常包括10例患者（4例单侧尿路扩张）的尿液浓缩能力缺陷。6例患者（3例单侧扩张）出现高钾血症，肾小管钾梯度低至3或更低且钾排泄分数低，提示远端肾小管醛固酮抵抗。尽管肾小管功能障碍在单侧病变中很常见，但随着严重程度评分和双侧性的增加，其发生率更高。
肾小管功能障碍在单侧或双侧肾积水婴儿中很常见。尽管这些异常很少危及生命且通常为自限性，但这些异常的代谢后果需要进行调查，以便进行适当的医疗管理。
