Hyponatremia Treatment Guidelines 2007: Expert Panel Recommendations

Abstract

Although hyponatremia is a common, usually mild, and relatively asymptomatic disorder of electrolytes, acute severe hyponatremia can cause substantial morbidity and mortality, particularly in patients with concomitant disease. In addition, overly rapid correction of chronic hyponatremia can cause severe neurologic deficits and death, and optimal treatment strategies for such cases are not established. Hyponatremia is the most common disorder of electrolytes encountered in clinical practice, occurring in up to 15% to 30% of both acutely and chronically hospitalized patients. 1 Although most cases are mild and relatively asymptomatic, hyponatremia is important clinically because: (1) acute severe hyponatremia can cause substantial morbidity and mortality; (2) mortality is higher in patients with hyponatremia who have a wide range of underlying diseases; and (3) overly rapid correction of chronic hyponatremia can cause severe neurologic deficits and death.Despite knowledge of hyponatremia since the mid-20th century, this common disorder remains incompletely understood in many basic areas because of its association with a plethora of underlying disease states, and its multiple etiologies with differing pathophysiologic mechanisms. 2 Optimal treatment strategies have not been well defined, both for these reasons and because of marked differences in symptomatology and clinical outcomes based on the acuteness or chronicity of the hyponatremia. 3 Vasopressin receptor antagonists have long been anticipated as a more effective method to treat hyponatremia by virtue of their unique aquaretic effect to selectively increase solute-free water excretion by the kidneys. 4 The recent approval of the first such agent, conivaptan, for clinical use by the US Food and Drug Administration (FDA) heralds the beginning of a new era in the management of hyponatremic disorders. However, effective therapy with these agents will require intelligent guidelines for their use. To this end, a panel of experts in hyponatremia convened to review current therapies for hyponatremia and to evaluate the situations in which aquaretic agents should be considered as alternatives or supplements to accepted current therapies. This review is a summary of the conclusions of this panel.

Hyponatremia and Mortality

“…Some have shown better outcomes with rapid correction rates (22), whereas others have found this to be associated with excess neurologic damage (23). The "correction rate debate" has somewhat settled on experts' consensus of a limit of 10 to 12 mmol/L per d, in which initial rates may be faster if hyponatremia is certain to be acute, and rates should be slower if hyponatremia is likely chronic (24). Perhaps it is not so much the optimal correction rate that is key to better outcomes but rather the prevention of hyponatremia.…”

Les troubles de l’équilibre hydrosodé chez les patients hospitalisés

“…]. 53 For the most part, these drugs have been used for hyponatremia associated with normovolemic or edematous states (i.e., SIADH, heart failure). [57][58][59][60][61][62] While preliminary data are promising that these agents may be alternatives to fluid restriction or saline administration, clinical experience is limited, particularly to support their use in managing acute severe hyponatremia.…”

“…Therefore, the rate of correction should ideally be limited to B10 mmol l -1 and B18 mmol l -1 over the first 24 and 48 h, respectively. 53 This course of action requires frequent monitoring of serum [Na ? ] in response to therapy and continual assessment for over-correction.…”

“…can be increased at a rate of 1.0 mmol l -1 per hour for 3-4 h; however, the same true rate of correction over the first 24 and 48 h should be observed. 53 For asymptomatic patients, serum [Na ? ] must be corrected slowly, as cerebral adaptation has occurred at a recommended rate \10-12 mmol l -1 and \18 mmol l -1 per 24 and 48 h, respectively.…”

“…must be corrected slowly, as cerebral adaptation has occurred at a recommended rate \10-12 mmol l -1 and \18 mmol l -1 per 24 and 48 h, respectively. 53 After correction of hyponatremia, the development of central pontine myelinolysis appears most commonly associated with the underlying chronicity of hyponatremia (i.e., allowance for cerebral adaptation) and the rate of rise of serum [Na ? ] within the first 48 h. 54 Sterns et al 54 found no neurologic complications for patients with serum [Na ? ]…”