Abstract
Measurement of the urinary sodium concentration can often help differentiate the various etiologies of hyponatremia. An elevated urinary sodium concentration is detected in the syndrome of inappropriate antidiuretic hormone (SIADH); however, the use of diuretics confounds the validity of this measurement. In this Practice Point commentary, I discuss the findings of Fenske et al., who suggest that the fractional excretion of uric acid (FEUA) is the best biomarker to determine whether hyponatremia is caused by SIADH in patients taking diuretics. An FEUA cutoff ≥12% had a positive predictive value of 100% for a diagnosis of SIADH in patients receiving diuretics, whereas an FEUA <8% excluded SIADH in this group. Here, I place the findings of Fenske et al. into clinical context, and discuss the utility of the FEUA and other biochemical markers for the diagnosis of SIADH in the presence of diuretics.
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References
Fenske W et al. (2008) Value of fractional uric acid excretion in differential diagnosis of hyponatremic patients on diuretics. J Clin Endocrinol Metab 93: 2991–2997
Decaux G et al. (1985) Mechanisms of hypouricemia in the syndrome of inappropriate secretion of antidiuretic hormone. Nephron 39: 164–168
Milionis HJ et al. (2002) The hyponatremic patient: a systemic approach to laboratory diagnosis. CMAJ 166: 1056–1062
Liamis G et al. (2007) Uric acid homeostasis in the evaluation of diuretic-induced hyponatremia. J Investig Med 55: 36–44
Decaux G et al. (1994) Uric acid, anion gap and urea concentration in the diagnostic approach to hyponatremia. Clin Nephrol 42: 102–108
Decaux G et al. (2000) Evidence that chronicity of hyponatremia contributes to the high urate clearance observed in the syndrome of inappropriate antidiuretic hormone secretion. Am J Kidney Dis 36: 745–751
Sonnenblick M et al. (1988) Increased uric acid clearance in the syndrome of inappropriate secretion of antidiuretic hormone. Isr J Med Sci 24: 20–23
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Steinman, T. Can the fractional excretion of uric acid distinguish the etiology of hyponatremia in patients taking diuretics?. Nat Rev Endocrinol 4, 602–603 (2008). https://doi.org/10.1038/ncpendmet0973
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DOI: https://doi.org/10.1038/ncpendmet0973