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Hyponatremia Management

Notes

Hyponatremia Management

Acute (< 48 hrs) Hyponatremia Management

Overview

Time of Development

  • Acute (within last 48 hours)
  • Chronic (longer than 48 hours)

Key Symptoms

  • GI - Nausea or vomiting
  • Motor - Ataxia or tremor
  • Cognitive - Confusion, seizures, and coma

Key Physical Exam Findings

  • Peripheral edema from volume overload
  • Cerebral edema, which can manifest with neurological signs of coma

Severity

  • < 120 mEq/L is severe
  • 120 to 130 mEq/L is moderate
  • 130 to 135 mEq/L is mild

Common Acute Causes

  • IV fluid over-load in surgery
  • Water intoxication (marathon runners, psychotic polydipsia, etc...)

Management

Treatment Indication

  • Treat when sodium is < 130 mEq/L (if acute).

General Goal

  • The goal in all patients is general to get a 5 mEq/L increase over the first few hours but to avoid over-correction over 24 hours – so it's treat rapidly, early, monitor closely (hourly) and then level off to give the brain a chance to adapt and avoid osmotic demyelination.

Symptomatic

  • In any acutely symptomatic patient, you need to worry about the development of cerebral edema, so you need to treat rapidly to avoid increased intracranial pressure, so give a rapid 100 ML 3% hypertonic saline infusion (over 10 minutes) to any symptomatic patient.

Asymptomatic

  • If they are not acutely symptomatic, you can be less aggressive and use 50 ML of 3% saline, check sodium hourly, and repeat a bolus if needed.

Autocorrecting

  • If the acute hyponatremia is already autocorrecting (from water diuresis), NO saline bolus is needed, and you can just monitor hourly, again targeting a 5 mEq/L increase. Of course, if the sodium drops instead of increases, give the 50 ML 3% saline bolus.

Additional Management

  • Stop other IV fluids to avoid worsening the hyponatremia.
  • Restrict any electrolyte-free water intake.
  • Look for any underlying causes.
    • Look for meds that could contributing (thiazide diuretics)
    • Look for possible SIADH: recent surgery, pain, certain medications, etc...
  • In SIADH, you'll want to consider additional treatments (salt tablets, loop diuretics, etc…).