Nephrology Book


Aka: Hyponatremia, Low Serum Sodium
  1. Definition
    1. Serum Sodium < 135 meq/L
  2. Pathophysiology
    1. Hypoosmolar Hyponatremia is most common
    2. Sodium is the principal osmole
    3. Hyponatremia is a water excess state
  3. Symptoms: Acute Hyponatremia (develops over <24 hours)
    1. Symptom onset when Serum Sodium <125 meq/L
    2. Initial
      1. Nausea
      2. Vomiting
      3. Headache
    3. Later or Severe (Serum Sodium <120 meq/L)
      1. Seizure
      2. Coma
      3. Respiratory arrest
  4. Symptoms: Chronic Hyponatremia (develops over >48 hours)
    1. Lethargy
    2. Confusion
    3. Muscle cramps
    4. Neurologic Impairment
  5. Prognosis: Mortality
    1. Acute Hyponatremia (Serum Sodium <120 meq/L): 50%
      1. Mortality associated with cerebral edema
    2. Chronic Hyponatremia: 10%
      1. Mortality associated with underlying condition
  6. Approach
    1. Is patient hypervolemic?
      1. See Hypervolemic Hypoosmolar Hyponatremia
    2. Measure Serum Osmolarity
      1. Hyperosmolar Hyponatremia (Serum Osms >300)
      2. Hypoosmolar Hyponatremia (Serum Osms <280)
        1. Hypovolemic Hypoosmolar Hyponatremia
        2. Isovolemic Hypoosmolar Hyponatremia
        3. Hypervolemic Hypoosmolar Hyponatremia
      3. Normoosmolar Hyponatremia (Serum Osms 280-300)
  7. Management
    1. See specific Hyponatremia protocols based on Serum Osms
    2. See Hyponatremia Management
  8. References
    1. Kone in Tisher (1993) Nephrology, p. 87-100
    2. Levinsky in Wilson (1991) Harrison's IM, p. 281-84
    3. Rose (1989) Acid-Base and Electrolytes, p. 601-38

Hyponatremia (C0020625)

Definition (NCI) Lower than normal levels of sodium in the circulating blood.
Definition (NCI) A disorder characterized by laboratory test results that indicate a low concentration of sodium in the blood.
Definition (MSH) Deficiency of sodium in the blood; salt depletion. (Dorland, 27th ed)
Definition (PSY) Abnormally low blood sodium level.
Definition (CSP) abnormally low sodium levels in the blood; salt depletion.
Concepts Finding (T033)
MSH D007010
ICD10 E87.1
SnomedCT 89627008, 154756008, 190880004, 267507003
English Sodium, decreased level, Hyponatremias, HYPONATRAEMIA, HYPONATREMIA, LOW SALT SYNDROME, LOW SODIUM SYNDROME, SALT DEFICIENCY, SERUM SODIUM DECREASED, SODIUM BLOOD DECREASED, SODIUM DEPLETION, SYNDROME LOW SALT, Hyponatremia, NOS, Hyponatraemia, NOS, Hyponatremia, Sodium Serum Decreased, Decreased serum sodium, Hyponatremia syndrome, hyponatremia (diagnosis), hyponatremia, Blood sodium decreased, Sodium blood decreased, Na+ depletion, Sodium depletion, Hyponatraemic syndrome, Low salt syndrome, Syndrome low salt, Low sodium syndrome, Sodium [Na] deficiency, Hyponatremia [Disease/Finding], salt deficiency, depletion sodium, hyponatremia syndrome, decreasing level sodium, decreased serum sodium, deficiency salt, deficiency sodium, deficiencies sodium, sodium depletion, sodium deficiency, Serum sodium decreased, Hyponatremic syndrome, Hyponatraemia, Hyponatremia (disorder), hyponatremic; syndrome, low; salt syndrome, salt; syndrome, low, sodium; depletion, syndrome; hyponatremic, syndrome; salt, low, hyponatraemia
French HYPONATREMIE, Déplétion de Na+, Syndrome hyposodique, Sodium sanguin diminué, Sodium sérique diminué, Déplétion sodée, Syndrome de carence en sel, DEFICIT EN SEL, DEPERDITION SODIQUE, DIMINUTION DE LA NATREMIE, SYNDROME HYPONATREMIQUE, SYNDROME LIE A DEFICIENCE EN SEL, Natrémie diminuée, Syndrome hyponatrémique, Hyponatrémie
Portuguese HIPONATREMIA, Síndrome hiponatrémica, Síndrome hipossalina, Síndrome hiponatrémico, Sódio diminuído no sangue, Depleção de Na+, Sódio sérico diminuído, Depleção de sódio, BAIXA DO SODIO SERICO, DEFICIENCIA EM SAL, DEPLECCAO SODICA, SINDROME DE DEFICIENCIA EM SAL, SINDROME HIPONATREMICO, Natremia diminuída, Síndrome de hiponatremia, Hiponatremia
Spanish HIPONATREMIA, Depleción de Na+, Síndrome de depleción de sal, Síndrome de sodio bajo, Síndromé por déficit de sal, Depleción de sodio, Sodio disminuido sérico, Hyponatremia, Hyponatraemia, HIPOSALINO, SINDROME, SAL, DEFICIENCIA, SODIO BAJO, SINDROME, SODIO PLASMATICO DISMINUIDO, SODIO, DEPLECION, hiponatremia (trastorno), hiponatremia, Sodio disminuido en sangre, Síndrome hiponatrémico, Hiponatremia
Italian Iponatremia, Sindrome iponatremica, Sindrome da iposodiemia, Sodio sierico diminuito, Sindrome iponatriemica, Deplezione di sodio, Sodio ematico diminuito, Deplezione di Na+, Iponatriemia
Dutch serum natrium verlaagd, natrium bloed verlaagd, syndroom laag sodium, Na+ depletie, natriumdepletie, laag zout syndroom, laag natrium syndroom, hyponatriëmisch; syndroom, laag; zoutsyndroom, natrium; depletie, syndroom; hyponatriëmisch, syndroom; zout, laag, zout; syndroom, laag, bloed natrium verlaagd, hyponatriëmie, hyponatriëmisch syndroom, Hyponatriëmie, Natriëmie, hypo-
German Natrium im Serum erniedrigt, Na+ Depletion, Natrium niedrig Syndrom, Natriumdepletion, Salz niedrig Syndrom, Syndrom, Salz niedrig, NATRIUMABFALL BLUT, NATRIUMMANGELSYNDROM, NATRIUMSPIEGEL ERNIEDRIGT, NATRIUMVERLUST, SALZMANGELSYNDROM, SALZMANGEL, Hyponatriaemie, Hyponatriaemie-Syndrom, Natrium im Blut erniedrigt, Hyponatriämie
Japanese 低ナトリウム症候群, ナトリウム欠乏, 低ナトリウム血症, 低ナトリウム血症候群, Na+欠乏, 血清ナトリウム減少, 血中ナトリウム減少, ナトリウムケツボウ, ケッチュウナトリウムゲンショウ, テイナトリウムケツショウ, テイナトリウムケッショウ, テイナトリウムケツショウコウグン, テイナトリウムショウコウグン, ケッセイナトリウムゲンショウ
Swedish Hyponatremi
Czech hyponatriémie, Snížený sodík v séru, Sodík v krvi snížený, Hyponatremie, Hyponatremický syndrom, Snížený sodík v krvi, Deplece sodíku
Finnish Hyponatremia
Polish Hiponatremia
Hungarian Sóhiányos syndroma, Szérum nátrium csökkent, Sóhiányos tünetegyüttes, Nátrium vérszint csökkent, Nátriumhiányos syndroma, Na+ depletio, Hyponatraemiás syndroma, Hyponatraemia, Nátrium depletio
Derived from the NIH UMLS (Unified Medical Language System)

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