Hypernatraemia
Standard Treatment Guidelines and Essential Medicines List for South Africa, Hospital Level, Adults 2019 Edition
E87.0
DESCRIPTION
A serum sodium level > 145 mmol/L.
- Mild to moderate symptoms: Lethargy, weakness, irritability
- Severe symptoms: Convulsions, coma
In patients who develop hypernatraemia outside of the hospital, it is usually due to water losses (decreased thirst sensation or inability to drink water, e.g. (delirium/reduced consciousness), gastro-intestinal losses (diarrhoea) or renal losses (diabetes insipidus)).
In hospitalised, critically ill patients it is usually the result of sodium gain (administration of too much sodium-containing intravenous solutions).
GENERAL MEASURES
Treat the cause.
Calculate the water deficit:
- Calculate Total body water = correction factor X weight (kg). Correction factor is 0.6 for men, 0.5 for women and elderly men, and 0.45 for elderly women.
- Calculate water deficit:
Click on image to enlarge.
See online calculator: https://www.msdmanuals.com/professional/multimedia/clinical-calculator/water-deficit-in-hypernatremia
MEDICINE TREATMENT
Correction fluid:
- Oral fluids or via NGT.
If unable to give fluids orally:
- Dextrose 5%, IV infusion.
- Monitor for hyperglycaemia. Rate of correction of hypernatraemia should be slower than 10 mmol/L over 24 hours to prevent cerebral oedema and rarely, osmotic demyelination syndrome.
Ongoing obligatory water loss through skin and stool (estimated at 30 mL/hour) must also be replaced:
LoE:IVbxxiii
- Calculate desired water replacement in the first 24 hours:
๐๐๐ก๐๐ ๐๐๐๐๐๐๐ก ร 10 ๐๐๐๐/๐ฟ รท (๐๐๐๐ข๐ [๐๐+] โ 140) - Calculate hourly infusion rate =
Desired water replacement in the first day รท 24 hours + 30 mL/hour.
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_7.2.3 Hypernatraemia