Both Tim, Hoorn Ewout J, Zietse Robert, van Laar Jan A M, Dalm Virgil A S H, Brkic Zana, Versnel Marjan A, van Hagen P Martin, van Daele Paul L A
Division of Clinical Immunology and Division of Nephrology and Transplantation, Department of Internal Medicine and Department of Immunology, Erasmus Medical Center, Rotterdam, The Netherlands
Division of Clinical Immunology and Division of Nephrology and Transplantation, Department of Internal Medicine and Department of Immunology, Erasmus Medical Center, Rotterdam, The Netherlands.
Rheumatology (Oxford). 2015 May;54(5):933-9. doi: 10.1093/rheumatology/keu401. Epub 2014 Oct 29.
Our objectives were to analyse the prevalence of distal renal tubular acidosis (dRTA) in primary SS (pSS) and to compare a novel urinary acidification test with furosemide and fludrocortisone (FF) with the gold standard ammonium chloride (NH4Cl) to detect dRTA.
Urinary acidification was assessed in 57 pSS patients using NH4Cl and FF. A urinary acidification defect was defined as an inability to reach a urinary pH of <5.3 after NH4Cl.
The prevalence of complete dRTA (urinary acidification defect with acidosis) was 5% (3/57). All three patients had positive SSA/Ro and SSB/La autoantibodies and impaired kidney function. The prevalence of incomplete dRTA (urinary acidification defect without acidosis) was 25% (14/57). Compared with patients without dRTA, patients with incomplete dRTA had significantly lower venous pH and serum bicarbonate and higher urinary pH. SSB/La antibodies were more prevalent in the dRTA groups (P < 0.05). Compared with NH4Cl, the positive and negative predictive values of FF were 46% and 82%, respectively. Vomiting occurred more often during the urinary acidification test with NH4Cl than with FF (9 vs 0, P < 0.05).
Incomplete dRTA is common in pSS and causes mild acidaemia and higher urinary pH, which may contribute to bone demineralization and kidney stone formation. FF cannot replace NH4Cl in testing urinary acidification in pSS, but may be considered as a screening tool, given its reasonable negative predictive value and better tolerability.
我们的目的是分析原发性干燥综合征（pSS）中远端肾小管酸中毒（dRTA）的患病率，并将一种新型速尿和氟氢可的松（FF）尿液酸化试验与检测dRTA的金标准氯化铵（NH₄Cl）试验进行比较。
使用NH₄Cl和FF对57例pSS患者的尿液酸化情况进行评估。尿液酸化缺陷定义为服用NH₄Cl后无法使尿液pH值<5.3。
完全性dRTA（伴有酸中毒的尿液酸化缺陷）的患病率为5%（3/57）。所有3例患者均有抗SSA/Ro和抗SSB/La自身抗体阳性且肾功能受损。不完全性dRTA（无酸中毒的尿液酸化缺陷）的患病率为25%（14/57）。与无dRTA的患者相比，不完全性dRTA患者的静脉血pH值和血清碳酸氢盐显著降低，尿液pH值升高。抗SSB/La抗体在dRTA组中更常见（P<0.05）。与NH₄Cl相比，FF的阳性预测值和阴性预测值分别为46%和82%。与FF相比，NH₄Cl尿液酸化试验期间呕吐更常发生（9例vs 0例，P<0.05）。
不完全性dRTA在pSS中常见，可导致轻度酸血症和尿液pH值升高，这可能导致骨质脱矿和肾结石形成。在pSS尿液酸化检测中，FF不能替代NH₄Cl，但鉴于其合理的阴性预测值和更好的耐受性，可作为一种筛查工具。
