see also:

• sodium physiology
• dehydration
• RCH guideline - hypernatraemia

• hypernatraemia may be life threatening if severe, of if sodium level rapidly rises or rapidly falls

• elderly patients with reduced thirst or ability to drink

• vomiting
• diarrhoea
• anorexia nervosa / eating disorders
• polyuria:
  • Diabetes insipidus
    • central
    • nephrogenic
  • glycosuria
  • solute diuresis
  • hypokalaemia
  • hypercalcaemia
  • renal disease

• if dehydrated with intravascular volume depletion, give initial 0.9% saline to restore intravascular volume, then “free-water” fluid Mx with an aim to slowly correct the hypernatraemia as below

• in general, no faster than 0.5mmol/L/hr, or 8-10 mmol/L per day
• those with severe acute hypernatraemia (documented as occurring over < 24hrs) can be considered for faster correction of 2-3mmol/L/hr for 2-3hrs and no more than 12mmol/L per day
• monitor electrolyte levels at least 4hrly

• see emedicine