Hyponatraemia
Standard Treatment Guidelines and Essential Medicines List for South Africa, Hospital Level, Adults 2019 Edition
E87.1
DESCRIPTION
A serum sodium level < 135 mmol/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.
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CAUTION Rapid correction of chronic hyponatraemia may lead to osmotic demyelination syndrome, which is often irreversible and fatal. Sodium should be frequently monitored, and increases should be <8 mmol/L per day. |
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Figure 1: Approach to hyponatraemia
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MEDICINE TREATMENT
In the presence of fluid overload:
- Furosemide, oral, 40 mg twice a day in divided doses.
- Increase dose to control signs of fluid overload and to improve hyponatraemia.
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In the absence of fluid overload:
Consult with a specialist before administering sodium chloride, IV infusion.
- Sodium chloride, IV infusion. (see table 1 below)
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CAUTION
Hypertonic sodium chloride should be reserved for severe acute hyponatraemia (sodium level <120 mmol/L with severe symptoms) and exceptional circumstances. In general, each increase in TBW of 1 mmol will raise the serum sodium concentration by 1 mmol/L. |
| 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 hyponatraemia: - 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%, 30mL as an IV bolus over 15min | Symptomatic relief Correct hyponatraemia: - 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 |
Table 1: Management of hyponatraemia with sodium chloride.
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To calculate the infusion rate, consult a specialist. https://reference.medscape.com/calculator/643/sodium-correction-rate-for-hyponatremia
Standard Treatment Guidelines and Essential Medicines List for South Africa, Adult Hospital Level, 2020-2024_Version 1.0_17 October 2024
Chapter 7 Nephrology/Urological Disorders_7.2 Major Electrolyte Abnormalities_7.2.4 Hyponatraemia