Mild Chronic Hyponatremia in the Ambulatory Setting

Abstract

Mild chronic hyponatremia, as defined by a persistent (>72 hours) plasma sodium concentration between 125 and 135 mEq/L without apparent symptoms, is common in ambulatory patients and generally perceived as being inconsequential. The association between increased mortality and hyponatremia in hospitalized patients in various settings and etiologies is widely recognized. This review analyzes the significance of mild chronic hyponatremia in ambulatory subjects and its effects on mortality and morbidity. It addresses whether this disorder should even be treated and if so, which patients are likely to benefit from treatment. The available approaches to correct hyponatremia in such patients in the context of recently published panel-generated recommendations and guidelines are described.

Urea for the Treatment of Hyponatremia

“…Hyponatremia, defined as a plasma sodium ,135 mEq/L, is the most common electrolyte disorder, and it is associated with increased mortality (1) and health resource utilization (2) in hospitalized patients. It has also been recently recognized that mild and seemingly asymptomatic hyponatremia is associated increased morbidity, including neurocognitive deficits, gait disturbances, falls, bone fractures, and osteoporosis (3). Although standard therapeutic interventions for hyponatremia, including fluid restriction and oral sodium chloride tablets, are commonly used (4), evidence of their efficacy from clinical trials is lacking.…”

“…Although standard therapeutic interventions for hyponatremia, including fluid restriction and oral sodium chloride tablets, are commonly used (4), evidence of their efficacy from clinical trials is lacking. Moreover, patient adherence to these treatments, particularly fluid restriction, is commonly suboptimal (3). The discovery of vasopressin antagonists provided a new drug class targeting elevated vasopressin levels that mediate most forms of hyponatremia (5).…”

Association of serum sodium levels with all‐cause and cardiovascular mortality in chronic kidney disease: Results from a prospective observational study

“…However, there has been no study that has investigated cardiovascular deaths in relation to dysnatraemia in non‐dialysis chronic kidney disease (CKD) patients in an ambulatory setting. The authors of a recent review acknowledge that there have been many studies performed in ambulatory participants in the general population, but none specific to renal disease …”

Hyponatremia in solid-tumor cancer patients: uncertainty regarding the use of vaptans

“…Mild chronic hyponatremia, defined as a persistent (>72 h) plasma sodium concentration of between 125 and 135 mmol/L without apparent symptoms, is common in ambulatory patients and is generally perceived as inconsequential. The relationship between increased mortality and the presence of hyponatremia in these patients is widely recognized and has been reviewed recently [8]. De las Peñas et al failed to mention the fundamental prerequisite for the management of these patients: restricted water intake [1].…”

“…De las Peñas et al failed to mention the fundamental prerequisite for the management of these patients: restricted water intake [1]. Although fluid intake is difficult to controldetermining which beverages are permitted and their individual tolerances-and its efficacy has only been demonstrated for a population of children with meningitis, a restricted fluid regimen should probably be prescribed systematically [8] Finally, few studies have thus far compared vasopressin antagonists with alternative treatment methods for hyponatremia [9]. In our opinion-and in accordance with the current European guidelines-a second-line therapy (following fluid restriction) with urea, prescribed at daily divided doses of 30-60 g, should be preferred to the use of vaptans for the treatment of SIADH [3].…”