Department of Paediatrics, Paediatric Nephrology, Ghent University Hospital, De Pintelaan 185, Ghent, Belgium.
Eur J Pediatr. 2018 Jan;177(1):79-84. doi: 10.1007/s00431-017-3029-2. Epub 2017 Oct 11.
There is evidence pointing to a decrease of the glomerular filtration rate (GFR) in a subgroup of nephrotic children, likely secondary to hypovolemia. The aim of this study is to validate the use of urinary potassium to the sum of potassium plus sodium ratio (UK/UK+UNa) as an indicator of hypovolemia in nephrotic syndrome, enabling detection of those patients who will benefit from albumin infusion. We prospectively studied 44 nephrotic children and compared different parameters to a control group (36 children). Renal perfusion and glomerular permeability were assessed by measuring clearance of para-aminohippurate and inulin. Vaso-active hormones and urinary sodium and potassium were also measured. Subjects were grouped into low, normal, and high GFR groups. In the low GFR group, significantly lower renal plasma flow (p = 0.01), filtration fraction (p = 0.01), and higher UK/UK+UNa (p = 0.03) ratio were noted. In addition, non-significant higher plasma renin activity (p = 0.11) and aldosteron (p = 0.09) were also seen in the low GFR group.
A subgroup of patients in nephrotic syndrome has a decrease in glomerular filtration, apparently related to hypovolemia which likely can be detected by a urinary potassium to potassium plus sodium ratio > 0.5-0.6 suggesting benefit of albumin infusion in this subgroup. What is Known: • Volume status can be difficult to assess based on clinical parameters in nephrotic syndrome, and albumin infusion can be associated with development of pulmonary edema and fluid overload in these patients. What is New: • Urinary potassium to the sum of urinary potassium plus sodium ratio can accurately detect hypovolemia in nephrotic syndrome and thus identify those children who would probably respond to albumin infusion.
有证据表明，一部分肾病儿童的肾小球滤过率（GFR）下降，可能继发于血容量不足。本研究旨在验证尿钾与钾钠比之和（UK/UK+UNa）作为肾病综合征血容量不足的指标的适用性，从而发现那些可能受益于白蛋白输注的患者。我们前瞻性地研究了 44 名肾病儿童，并将不同参数与对照组（36 名儿童）进行了比较。通过测量对氨基马尿酸和菊粉的清除率来评估肾灌注和肾小球通透性。还测量了血管活性激素和尿钠、尿钾。将研究对象分为低、正常和高 GFR 组。在低 GFR 组中，肾血浆流量（p=0.01）、滤过分数（p=0.01）显著降低，UK/UK+UNa 比值更高（p=0.03）。此外，低 GFR 组的血浆肾素活性（p=0.11）和醛固酮（p=0.09）也略有升高。
肾病综合征患者中存在肾小球滤过率下降的亚组，显然与血容量不足有关，通过尿钾与钾钠比比值>0.5-0.6 可以检测到这种情况，提示该亚组可能受益于白蛋白输注。已知：• 根据肾病综合征的临床参数，很难评估容量状态，白蛋白输注可能会导致这些患者发生肺水肿和液体超负荷。新发现：• 尿钾与尿钾加钠比值可以准确检测肾病综合征中的血容量不足，从而识别那些可能对白蛋白输注有反应的儿童。
