Introduction
The reference range for sodium is 135 mmol/L - 145 mmol/L
Interpretation
Causes of hyponatraemia
Causes of hypernatraemia
- diuretics: thiazides, loop diuretics
- SIADH
- diarrhoea, vomiting, sweating
- IV dextrose, psychogenic polydipsia
- secondary hyperaldosteronism: heart failure, liver cirrhosis
- burns
- Addison's disease
- diuretic stage of renal failure
- hypothyroidism
Causes of hypernatraemia
- dehydration
- osmotic diuresis e.g. hyperosmolar non-ketotic diabetic coma
- diabetes insipidus
- excess IV saline