Hyponatraemia

E87.1

DESCRIPTION

A serum sodium level <135mmol/L.

Mild to moderate symptoms: Headache, nausea, vomiting, fatigue, gait disturbances, and confusion.
Severe symptoms: Seizures, obtundation, coma, and respiratory arrest.

Acute hyponatraemia develops within hours due to self-inflicted water-intoxication.

Rapid correction may lead to central pontine myelinolysis, which is often irreversible. Sodium should be frequently monitored and increases should be <9 mmol/L per day.

APPROACH

HYPONATRAEMIA.jpg

MEDICINE TREATMENT

In the presence of fluid overload:

  • Furosemide, oral, 40 mg 12 hourly.
    • Increase dose to control signs of fluid overload and to improve hyponatraemia.

LoEIII [13]

In the absence of fluid overload:

Consult with a specialist before administering sodium chloride, IV infusion.

  • Sodium chloride, IV infusion.

CAUTION

Hypertonic sodium chloride should be reserved for severe acute hyponatraemia (sodium level <120 mmol/L with severe symptoms) and exceptional circumstances.

One litre of NaCl infusate Total Na (mmol/l) Indication Fluid Aim
5% NaCl

Expect an increase of 2-3 mmol/L for every 60 mL 		855
  • Sodium level < 120 mmol/L and
  • Severe symptoms (see above).
    or
  • Acute hyponatraemia due to water intoxication.
    		•  • Hypertonic sodium chloride, 5%, 60 mL as an IV bolus over 15 min

  • If symptoms persist/ worsens or sodium is not improving, consult a specialist
    		•
  • Symptom relief

  • Correct hypona-traemia:
    - 4-6 mmol/L immediately
    AND
    - Maximum 8 mmol/L in 1st 24 hrs
    		•
    5% NaCl

    Expect an increase of 2-3 mmol/L for every 60 mL     		855
  • Sodium level <120 mmol/L with mild to moderate symptoms

    • or
  • Chronic hyponatraemia
  • Hypertonic sodium chloride, 5%, 30 mL as an IV bolus over 15 min
    		•
  • Symptomatic relief.

  • Correct hypona-traemia:
    - Maximum 8 mmol/L in 1st 24 hrs
    • 0,9% NaCl 154
  • Sodium level >120 mmol/L

  • Dehydrated.

  • Asymptomatic or mild symptoms
    		•
  • Sodium chloride, 0.9%, IV infusion, 1L 8 hourly
  • Rehydration.
    		•

    LoEIII [14]

    To calculate the infusion rate, consult a specialist. https://reference.medscape.com/calculator/643/sodium-correction-rate-for-hyponatremia