Toblli J E, Rosemffet M G, Hunter B, Barcelo H A, Ravaglia C, Cocco J A
Departamento de Medicina Interna, Hospital Alemán, Buenos Aires, Argentina.
Medicina (B Aires). 1996;56(2):150-4.
The aim of this study was to investigate subclinical abnormalities in renal function suggestive of incomplete distal renal tubular acidosis (DRTA) in patients with rheumatoid arthritis (RA), using the gradient between PCO2 in urine and blood (U-B PCO2 gradient), which is a simple and sensitive test. We prospectively selected 45 patients in three groups (G). G 1 (n = 15p), with RA, mean age 44 years and mean disease duration 6.5 years. G2 (n = 10 p), with RA and Sjögren's syndrome (SS), mean age 47 years and mean disease duration 6.6 years. G 3 (n = 20) healthy volunteers, no history neither renal nor rheumatic diseases, mean age 37 years. Patients in G1 and G2 had no history of concurrent disease affecting renal parenchyma, their acid-base status and renal function were normal (Creatinine clearance above 70 ml/min/1.73m2). All patients received NSAIDs but none gold salts and/or D-Penicillamine. The ability to acidify the urine was evaluated in all cases by U-B PCO2 gradient, after a 500 ml NaHCO3 continuous infusion 1 molar solution through a peripheral vein. U-B PCO2 lower than 30 was considered pathological and diagnostic for DRTA. The urinary specimen for pH and PCO2 were kept under mineral oil and processed within 5 minutes of excretion. The blood samples for PCO2 were obtained from a peripheral vein and measured after obtaining a urinary pH 7.8 or above, pH and PCO2 were measured with a BMS 3 MK2 Radiometer, Copenhagen Denmark electrode and analizer. The U-BPCO2 results were (mean 2 sd): G1 = 47 +/- 26; G2 = 49.8 +/- 8.4; G3 = 52.5 +/- 12.2. There were no statistical differences among the three groups (F = 1.228727). In the G1, a single patient presented U-B PCO2 lower than 30 (U-B PCO2 = 5), having a long active disease at the evaluation time. In G2 and G3 no gradient alterations were recorded. We conclude, in spite of the fact that U-B PCO2 gradient is a very useful and sensitive tool for detecting dRTA, that there was no correlation between incomplete type dRTA and RA or between incomplete dRTA and RA associated to SS. In addition, no association was found between NSAID intake and dRTA.
本研究旨在利用尿与血中二氧化碳分压梯度（U-B PCO2梯度）这一简单且敏感的检测方法，调查类风湿关节炎（RA）患者中提示不完全性远端肾小管酸中毒（DRTA）的肾功能亚临床异常情况。我们前瞻性地选取了45名患者，分为三组（G组）。G1组（n = 15人），患有RA，平均年龄44岁，平均病程6.5年。G2组（n = 10人），患有RA和干燥综合征（SS），平均年龄47岁，平均病程6.6年。G3组（n = 20人）为健康志愿者，无肾脏及风湿性疾病史，平均年龄37岁。G1组和G2组患者无影响肾实质的并发疾病史，其酸碱状态及肾功能正常（肌酐清除率高于70 ml/min/1.73m2）。所有患者均服用非甾体抗炎药，但均未服用金盐和/或青霉胺。所有病例在经外周静脉持续输注500 ml 1摩尔浓度的碳酸氢钠溶液后，通过U-B PCO2梯度评估尿液酸化能力。U-B PCO2低于30被视为病理性，可诊断为DRTA。用于检测pH值和PCO2的尿液样本保存在矿物油下，并在排出后5分钟内进行处理。用于检测PCO2的血液样本从外周静脉采集，在尿液pH值达到7.8或更高后进行测量，pH值和PCO2使用丹麦哥本哈根BMS 3 MK2辐射计电极和分析仪进行测量。U-B PCO2结果（均值±标准差）为：G1组 = 47 ± 26；G2组 = 49.8 ± 8.4；G3组 = 52.5 ± 12.2。三组之间无统计学差异（F = 1.228727）。在G1组中，有一名患者的U-B PCO2低于30（U-B PCO2 = 5），在评估时疾病处于活动期较长。G2组和G3组未记录到梯度改变。我们得出结论，尽管U-B PCO2梯度是检测dRTA的非常有用且敏感的工具，但不完全性dRTA与RA之间或不完全性dRTA与合并SS的RA之间并无关联。此外，未发现非甾体抗炎药的摄入与dRTA之间存在关联。
