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Treatment of Symptomatic Hyponatremia

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ABSTRACT

Inadequate treatment of severe hyponatremia (< 120 mEq/L) can be associated with severe neurological damage. In acute (< 48 hours) hyponatremia, usually observed in the postoperative period, prompt treatment with hypertonic saline (3%) can prevent seizures and respiratory arrest. For patients with chronic (> 48–72 hours) symptomatic hyponatremia, correction must be rapid during the first few hours (to decrease brain edema) followed by a slow correction limited to 10 mmol/L over 24 hours to avoid the development of osmotic demyelinating syndrome. In patients with asymptomatic hyponatremia, slow correction is the appropriate approach. When patients are overtreated, neurologic damage can be prevented by relowering the serum sodium (SNa) so that the daily increase in SNa remains below 10 mmol/L/24 hours. Frequent measurements of SNa during the correction phase of SNa are mandatory to avoid overcorrection. The use of urea to treat hyponatremia represents an advantageous alternative to hypertonic saline.

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Brain Adaptation to Hyponatremia and Its Treatment

Understanding of the most appropriate therapeutic approach in the presence of hyponatremia requires a brief physiopathologic review. When blood tonicity diminishes, the brain will rapidly lower the electrolyte content of its interstitial fluid (Na+ and Cl) within minutes; then, intracellular potassium and organic osmolytes such as amino acids (eg, taurine, glutamine, glutamate), polyols (myoinositol), methylamines (creatine, etc) decrease. This prevents excessive cerebral edema, 4 which could

Risk Factors for Myelinolysis (ODS)

The most important factor is the daily difference in serum sodium level. Furthermore, about 80% of cases of ODS reported in the literature are associated with hypokalemia (often induced by thiazides). 12 Most ODS observations were reported in patients presenting with an initial SNa below 120 mEq/L. 4 However, in malnourished patients (chronic alcohol abuse, liver cirrhosis, heavy burns, hypocorticism, etc), ODS cases were reported with less severe hyponatremia. 13

In animals, there is a good

Treatment of Acute Hyponatremia

The circumstances inducing hyponatremia are very important diagnostic clues to recognizing hyponatremia as acute or chronic. Acute hyponatremia occurs generally in hospitalized patients and is most frequently iatrogenic. The main causes are outlined in Table 1. Some symptoms suggest intracranial hypertension: headache, nausea, vomiting, seizures, and deep coma. Sometimes these symptoms may be explosive in nature.

Exercise-induced hyponatremia occurs in association with overwhelming physical

Treatment of Symptomatic Chronic Hyponatremia (> 48 to 72 Hours), Subacute Hyponatremia, or Hyponatremia of Undetermined Duration

The clinical context in which hyponatremia develops may be helpful in differentiating acute from chronic hyponatremia. Severe neurologic symptoms often reflect cerebral edema, but this is not always true. 21 Extrahospital acquired hyponatremia is generally chronic, except for polydipsia, marathon runners, and ecstasy. Chronic hyponatremia may have a superimposed acute component. Hyponatremia of undetermined duration, especially when it is symptomatic, needs treatment combining rapid decrease of

Relowering of the SNA in Case of Overcorrection of Hyponatremia

An excessive rate of correction of hyponatremia may be secondary to the excessive administration of salt (error in calculation of doses to administer), and we have to remember that the administration of potassium in the solution contributes to increase the serum sodium. Most often this is caused by a predictable or unpredictable increase in the excretion of electrolyte free water. 22., 23. Frequent monitoring of SNa should enable avoidance of this complication. Data obtained in animals suggest

General Recommendations

When hyponatremia is associated with severe neurologic symptoms (vomiting, headaches, seizures, coma, etc), rapid correction of hyponatremia during the first hours is mandatory (Table 4). However, there is no reason to increase SNa by more than 8 to 10%. If the acute nature of hyponatremia is obvious (postoperative, duration < 48 hours), normalization of SNa is theoretically possible without inducing cerebral lesions. In those patients in whom the duration of hyponatremia is not definitely

Urea as Alternative Treatment for Symptomatic Hyponatremia

Urea represents a valuable therapeutic alternative in hyponatremia 4 (Table 6). This endogenous diuretic is able to rapidly diminish cerebral edema without any risk of volume overload and without the risk of transitory worsening of hyponatremia (as seen with the administration of mannitol, caused by water translocation). 30 The osmotic diuresis caused by urea is accompanied by sodium retention that also plays a role in the correction of hyponatremia. 31 Urea may also be used as a long-term

References (41)

  • G. Decaux

    Difference in solute excretion during correction of hyponatremia in patients with cirrhosis or SIADH by oral vasopressin V2 receptor antagonist VPA-985

    J Lab Clin Med

    (2001)
  • G. Decaux et al.

    Hyponatremia in the intensive care: from diagnosis to treatment

    Acta Clinica Belg

    (2000)
  • R.J. Anderson et al.

    Hyponatremia: a prospective analysis of its epidemiology and the pathogenic role of vasopressin

    Ann Intern Med

    (1985)
  • A. Soupart et al.

    Therapeutic recommendations for management of severe hyponatremia: current concepts on pathogenesis and prevention of neurologic complications

    Clin Nephrol

    (1996)
  • A.I. Arieff

    Hyponatremia, convulsions, respiratory arrest and permanent brain damage after elective surgery in healthy women

    N Engl J Med

    (1986)
  • J.C. Ayus et al.

    Postoperative hyponatremic encephalopathy in menstruant women

    Ann Intern Med

    (1992)
  • Kleinschmidt-de MastersB.K. et al.

    Rapid correction of hyponatremia causes demyelination: relation to central pontine myelinolysis

    Science

    (1981)
  • Y.H. Lien

    Role of organic osmolytes in myelinolysis. A topographic study in rats after correction of hyponatremia

    J Clin Invest

    (1995)
  • P.H. Yancey et al.

    Living with water stress: evolution of osmolyte systems

    Science

    (1982)
  • R. Laureno

    Central pontine myelinolysis following rapid correction of hyponatremia

    Ann Neurol

    (1983)
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    Many studies were supported by grants from the “Fonds National de la Recherche Scientifique” (1.5.228.90F/1.5.204.91F/1.5.175.94F/1.5.193.96F/1.5.198.97F/1.5.164.98F/1.5.141.00F/4574.01).

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