Alvarado L C, Voyer L E, Bortolazzo G, Costa M A
Unidad de Nefrología, Hospital General de Niños Pedro de Elizalde, Buenos Aires, Argentina.
Medicina (B Aires). 1991;51(4):338-42.
The aim of this study was to investigate the effect of furosemide on urinary acidification in 7 healthy children (aged 7 to 9 years) 5 patients with normokalemic distal renal tubular acidosis (RTA) (aged 4 to 13 years) and in 1 patient with proximal RTA (aged 20 months). Furosemide was given (2 mg/kg orally) as a tool to stimulate H+ and K+ secretion by enhancing Na delivery and transport in distal tubular segments. Patients with distal RTA were diagnosed by means of the ammonium chloride test and the alkaline overload and the one with proximal RTA by the ammonium chloride test only. Urinary acidification was evaluated 1 hour before and until 4 hours after furosemide administration. Healthy children (Fig. 1) showed a significant fall in urinary pH, 5.8 +/- 0.27 to 4.88 +/- 0.18 (p less than 0.02) and increase of NH3 excretion from 38.58 +/- 10.33 to 79.09 +/- 10.38 microEq/min/1.73 m2 (p less than 0.05). There was a direct correlation between urinary pH and urinary flow: r = 0.62 p less than 0.01 (Fig. 3). In patients with distal RTA (Fig. 5) furosemide failed to lower urine pH below 6 and net acid excretion persisted low: 47.9 +/- 6.1 microEq/min/1.73 m2. In the patient with proximal RTA (Fig. 4) furosemide produced the same effect as in healthy children with a fall in urine pH to 4.4 and an increase in net acid excretion to 118 microEq/min/1.73 m2. Furosemide proved to be effective to differentiate the type of RTA.(ABSTRACT TRUNCATED AT 250 WORDS)
本研究旨在调查呋塞米对7名健康儿童（7至9岁）、5名正常血钾性远端肾小管酸中毒（RTA）患者（4至13岁）及1名近端RTA患者（20个月）尿液酸化的影响。给予呋塞米（2mg/kg口服），作为通过增强远端肾小管节段的钠递送和转运来刺激H⁺和K⁺分泌的工具。远端RTA患者通过氯化铵试验和碱负荷进行诊断，近端RTA患者仅通过氯化铵试验进行诊断。在给予呋塞米前1小时直至给药后4小时评估尿液酸化情况。健康儿童（图1）尿液pH值显著下降，从5.8±0.27降至4.88±0.18（p<0.02），NH₃排泄量从38.58±10.33增加至79.09±10.38微当量/分钟/1.73m²（p<0.05）。尿液pH值与尿流之间存在直接相关性：r=0.62，p<0.01（图3）。在远端RTA患者中（图5），呋塞米未能使尿液pH值降至6以下，净酸排泄持续较低：47.9±6.1微当量/分钟/1.73m²。在近端RTA患者中（图4），呋塞米产生了与健康儿童相同的效果，尿液pH值降至4.4，净酸排泄增加至118微当量/分钟/1.73m²。呋塞米被证明可有效区分RTA的类型。（摘要截断于250字）
