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Are We Ignoring Dysnatremia?

      SEE RELATED ARTICLE p. 1125.e1
      Dysnatremia is the most common electrolyte disturbance encountered in hospitals. In this issue, Arampatzis et al confirmed that dysnatremia also is common in patients visiting the emergency department.
      • Arampatzis S.
      • Frauchiger B.
      • Fiedler G.M.
      • et al.
      Characteristics, symptoms and outcome of severe dysnatremias present on hospital admission.
      About 10% of emergency department visitors whose serum electrolytes were measured at a tertiary hospital in Switzerland had hyponatremia (serum Na <135 mEq/L), and 2% had hypernatremia (serum Na >145 mEq/L). Detailed information on those with severe hyponatremia (Na <125) or hypernatremia (Na >149) was analyzed. About a quarter of them required critical care, and overall mortality was 13% and 28% for hyponatremia and hypernatremia, respectively, although dysnatremia was not the direct cause of death (Table).
      • Arampatzis S.
      • Frauchiger B.
      • Fiedler G.M.
      • et al.
      Characteristics, symptoms and outcome of severe dysnatremias present on hospital admission.
      TableOutcome of Severe Hyponatremia and Hypernatremia
      • Arampatzis S.
      • Frauchiger B.
      • Fiedler G.M.
      • et al.
      Characteristics, symptoms and outcome of severe dysnatremias present on hospital admission.
      Na <121 mEq/LNa >149 mEq/L
      ICU2623
      Death1328
      No Na level next day1446
      No treatment418
      Na worse with treatment210
      Na over-corrected
      Change of serum Na >12 mEq/day.
      114
      Na properly corrected5119
      ICU=intensive care unit.
      Numbers are % of total hyponatremic or hypernatremic patients.
      low asterisk Change of serum Na >12 mEq/day.
      The most concerning fact is that only 51% of patients with severe hyponatremia and 19% of those with severe hypernatremia had Na corrected by 12 mEq/day or less in the first day. For patients with hyponatremia, 14% did not have their Na level measured on the next day, and 4% were untreated. It is possible that some of them had terminal diseases, and only palliative care was provided. Among all hyponatremic patients, 21% received treatment, but hyponatremia was worse on the next day, and 11% were overtreated with an increment of Na >12 mEq/day. For hypernatremic patients, 64% of them did not have follow-up Na level or treatment. Only part of this inaction is due to terminal diseases because the mortality was 28%. Only 4% of all hypernatremic patients were overcorrected with a reduction of Na >12 mEq/day.
      Whether a similar report card would be found in other hospitals is not clear. Severe hypernatremia is associated with a high mortality rate. In 2 large series of hospitalized patients with hypernatremia, 30-day mortality was 37% (Na >155)
      • Alshayeb H.M.
      • Showkat A.
      • Babar F.
      • Mangold T.
      • Wall B.M.
      Severe hypernatremia correction rate and mortality in hospitalized patients.
      and 41% (Na >150),
      • Palevsky P.M.
      • Bhagrath R.
      • Greenberg A.
      Hypernatremia in hospitalized patients.
      respectively. Palevsky et al
      • Palevsky P.M.
      • Bhagrath R.
      • Greenberg A.
      Hypernatremia in hospitalized patients.
      reported that 49% of hypernatremic patients did not receive hypotonic fluid within 24 hours of diagnosis. Hypernatremia was corrected in 47% by 72 hours.
      • Palevsky P.M.
      • Bhagrath R.
      • Greenberg A.
      Hypernatremia in hospitalized patients.
      In the other series, only 27% had hypernatremia corrected by 72 hours. More importantly, a slower correction rate of hypernatremia in the first 24 hours (<0.25 mEq/L/h) is an independent predictor of 30-day mortality (hazards ratio 2.63).
      • Alshayeb H.M.
      • Showkat A.
      • Babar F.
      • Mangold T.
      • Wall B.M.
      Severe hypernatremia correction rate and mortality in hospitalized patients.
      It appears that delayed and inadequate treatment for hypernatremia is quite common and may have serious consequences, including death.
      The deficits in hyponatremia management seem to be somewhat different from those in hypernatremia. Unlike hypernatremic patients, patients with hyponatremia often receive treatment early, but the problem is that their Na levels are not corrected as recommended by the guidelines. The pathogenesis of hyponatremia is complicated and can be associated with hypovolemia, hypervolemia, or euvolemia.
      • Lien Y.H.
      • Shapiro J.I.
      Hyponatremia: clinical diagnosis and management.
      Proper treatment of hyponatremia relies on identification of the cause of hyponatremia. Fenske et al
      • Fenske W.
      • Maier S.K.
      • Blechschmidt A.
      • Allolio B.
      • Stork S.
      Utility and limitations of the traditional diagnostic approach to hyponatremia: a diagnostic study.
      have shown that the accuracy of senior intensive care unit physicians in diagnosing etiologies of hyponatremia is only 32%. As a result, under- or overtreatment of hyponatremia does occur. It is well known that over-correction of hyponatremia is associated with osmotic demyelination syndrome,
      • Kleinschmidt-DeMasters B.K.
      • Norenberg M.D.
      Rapid correction of hyponatremia causes demyelination: relation to central pontine myelinolysis.
      however, undertreatment increases mortality.
      • Waikar S.S.
      • Mount D.B.
      • Curhan G.C.
      Mortality after hospitalization with mild, moderate, and severe hyponatremia.
      With the addition of vasopressin receptor antagonists for treating hypervolemic and euvolemic hyponatremia,
      • Berl T.
      • Quittnat-Pelletier F.
      • Verbalis J.G.
      • et al.
      Oral tolvaptan is safe and effective in chronic hyponatremia.
      we should be able to avoid undertreatment. The key for successful treatment of severe hyponatremia is frequent monitoring of Na level and adjusting treatment accordingly. We have recently experienced a case of unexpected massive aquaresis after tolvaptan treatment for hyponatremia and albumin infusion for paracentesis. We were able to avoid a potential catastrophe by close monitoring of Na level and adjusting fluid management.
      • Cho C.
      • Logan J.L.
      • Lien Y.H.
      Massive aquaresis after tolvaptan administration and albumin infusion in a patient with alcoholic cirrhosis.
      Although dysnatremia per se rarely causes mortality, its presence always indicates something wrong with the body and frequently predicts clinical outcomes. We should not ignore dysnatremia. It is time to face the challenge of identifying the causes of dysnatremia and carrying out a treatment plan to properly correct them.

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