Department of Medicine, Division of Nephrology and Hypertension, NYU Langone Hospital Long Island and NYU Long Island School of Medicines, Mineola, New York, NY 11501, USA.
Biomolecules. 2023 Apr 1;13(4):638. doi: 10.3390/biom13040638.
The application of pathophysiologic tenets has created significant changes in our approach to hyponatremia and hyponatremia-related conditions. This new approach incorporated the determination of fractional excretion (FE) of urate before and after the correction of hyponatremia and the response to isotonic saline infusion to differentiate the syndrome of inappropriate secretion of antidiuretic hormone (SIADH) from renal salt wasting (RSW). FEurate simplified the identification of the different causes of hyponatremia, especially the diagnosis of a reset osmostat and Addison's disease. Differentiating SIADH from RSW has been extremely difficult because both syndromes present with identical clinical parameters, which could be overcome by successfully carrying out the difficult protocol of this new approach. A study of 62 hyponatremic patients from the general medical wards of the hospital identified 17 (27%) to have SIADH, 19 (31%) with reset osmostat, and 24 (38%) with RSW with 21 of these RSW patients presenting without clinical evidence of cerebral disease to warrant changing the nomenclature from cerebral to renal salt wasting. The natriuretic activity found in the plasma of 21 and 18 patients with neurosurgical and Alzheimer's disease, respectively, was later identified as haptoglobin-related protein without signal peptide (HPRWSP). The high prevalence of RSW creates a therapeutic dilemma of deciding whether to water-restrict water-logged patients with SIADH as compared to administering saline to volume-depleted patients with RSW. Future studies will hopefully achieve the following: 1. Abandon the ineffective volume approach; 2. Develop HPRWSP as a biomarker to identify hyponatremic and a projected large number of normonatremic patients at risk of developing RSW, including Alzheimer's disease; 3. Facilitate differentiating SIADH from RSW on the first encounter and improve clinical outcomes.
病理生理原理的应用在我们对低钠血症和低钠血症相关疾病的治疗方法上带来了重大改变。这种新方法包括在纠正低钠血症前后测定尿酸的分数排泄（FE），以及对等渗盐水输注的反应，以区分抗利尿激素分泌不当综合征（SIADH）和肾性盐耗（RSW）。FEurate 简化了低钠血症不同病因的识别，特别是重置渗透压感受器和艾迪生病的诊断。区分 SIADH 和 RSW 一直非常困难，因为这两种综合征都具有相同的临床参数，而这可以通过成功实施这种新方法的困难方案来克服。对来自医院普通内科病房的 62 名低钠血症患者的研究发现，17 名（27%）患有 SIADH，19 名（31%）患有重置渗透压感受器，24 名（38%）患有 RSW，其中 21 名 RSW 患者没有临床证据表明患有脑部疾病，因此将命名从脑性盐耗改为肾性盐耗。在分别患有神经外科和阿尔茨海默病的 21 名和 18 名患者的血浆中发现的利钠活性后来被鉴定为无信号肽的结合珠蛋白相关蛋白（HPRWSP）。RSW 的高患病率造成了一个治疗上的困境，即需要决定是限制水摄入治疗患有 SIADH 的水潴留患者，还是给患有 RSW 的容量不足患者输注盐水。未来的研究有望实现以下目标：1. 摒弃无效的容量治疗方法；2. 开发 HPRWSP 作为生物标志物，以识别低钠血症和大量预计会发生 RSW 的正常钠血症患者，包括阿尔茨海默病患者；3. 首次就诊时有助于区分 SIADH 和 RSW，并改善临床结果。
