Evaluation of Blood Volume State Using the Quotient of Urine Sodium and Potassium Excretion in Primary Nephrotic Syndrome in Children

ABSTRACT

PURPOSE: Edema is one of the cardinal features of nephrotic syndrome. Although the pathogenesis of edema is not entirely understood, it is caused by hypovolemia or hypervolemia by different mechanisms. Accordingly it is important to evaluate the volume status of patients in order to treat the edema, but it is difficult to evaluate the patient's volume status only by clinical parameters. The quotient of urine sodium and potassium excretion UK/(UNa+UK) is introduced as a more useful way to evaluate volume status. In this study we will propose the usefulness of UK/(UNa+UK) in evaluating the volume status of children with nephrotic syndrome. METHODS: Primary nephrotic syndrome patients at Yeungnam University Hospital since January 1995 to June 2005, were included in the study. We analyzed clinical parameters such as tachycardia, cardiomegaly, pleural effusion, blood chemistry and urinalysis prospectively. We defined hypovolemia when UK/(UNa+UK) exceeded 60%. Intravenous albumin and diuretics were administered to hypovolemic edematous patients. On the other hand, hypervolemic edematous patients were treated only with diuretics. RESULTS: There were 50 cases of primary nephrotic syndrome patients(hypervolemia 29 vs hypovolemia 21). There were no significant differences in clinical symptoms and laboratory findings except for FeNa. While FeNa and UK/(UNa+UK) had a significant negative correlation, BUN and UK/(UNa+UK) had a significant positive correlation. Urine output after edema treatment was effective and there were no treatment-related side effects in both groups. CONCLUSION: FeNa, BUN and UK/(UNa+UK) are a useful parameters for evaluating volume status of edematous nephrotic syndrome patients. We could suggest a therapeutic option for using albumin and/or diuretics according to volemic status by means of measured UK/(UNa+UK).