Investigation Of NT-proBNP Level In Hyponatremia Due To Endocrine Causes

Research Article

Abstract

Introtuction: Inappropriate ADH secretion syndrome and pituitary insufficiency are endocrine causes of hyponatremia. The main reason in both groups is the direct or indirect increase in ADH secretion.Fluid retention occurs with the increase in ADH secretion. Fluid retention leads to cardiac strain, and it is thought that it may cause increased secretion of BNP and NT-proBNP .

Aim: Studies on the effects of natriuretic peptides on hyponatremia are scarce due to endocrine causes. The relationship between thyroid hormone disorders and Brain natriuretic peptide (BNP) has been examined in existing studies. Within the scope of this research.we aimed to elucidate the relationship between NT-proBNP and hyponatremia in inappropriate ADH secretion syndrome and pituitary insufficiency.

Method: This prospective study included 14 patients with hyponatremia, inappropriate ADH secretion syndrome, nine patients with pituitary insufficiency who applied to our institution, and 21 healthy volunteers with no systemic disease and serum sodium levels within the normal range. Laboratory tests of the patient group (fasting blood sugar, serum sodium level, spot urine sodium, creatinine, urine osmolarity, and anterior pituitary hormones of patients with suspected pituitary insufficiency) were recorded from the patient files .

Results: Basal sodium levels were statistically significant among the three groups. The median basal sodium level was 127 (meq/l) in the pituitary insufficiency group, 124 (meq/l) in the inappropriate ADH secretion syndrome group, and 138 (meq/l) in the control group (p<0.0001). The median NT-proBNP level was found to be 671 (pg/ml) in the pituitary insufficiency group, 499 (pg/ml) in the inappropriate ADH secretion syndrome group, and 119 (pg/ml) in the control group (p<0.0001). As a result of ROC analysis, serum NT-proBNP values were found to have diagnostic value in predicting hyponatremia due to endocrinological reasons (inappropriate ADH secretion syndrome and pituitary insufficiency) (AUC:0.87 95% confidence interval 0.763 – 0.977, p<0.0001). This value's recommended limit value is 141 (sensitivity: 91.3% and specificity: 66.7%).

Conclusion: This research elaborated that while plasma sodium levels were low in the inappropriate ADH secretion syndrome and pituitary insufficiency groups, the NT-proBNP levels were higher, showing a statistically significant difference between the three groups.