Hypernatraemia

Usually due to ↓ free water in ICU context
Can cause delirium (thirst!!)

  • The alert but not thirsty hypernatraemia patient has a hypothalamic problem

things we do that cause hypernatraemia

  • Na/K administration
    • usually from fluids and meds that we're giving
  • not enough free water
  • ↑ GI water loss - vomiting, NG aspirate, diarrhoea incl. osmotic laxatives
  • renal water loss due to diabetes insipidus
  • diuresis
    • loop diuretics
    • SGLT-2 inhibitors
    • polyuric phase of AKI recovery (when urea gets cleared, it takes water with it)

clinical features

  • Hyperreflexia, myoclonic jerks, nystagmus. (36578134)
  • Weakness

investigations

  • Urine Osm (physiologically expect to be high → inappropriately low or normal Osm suggest DI)

management approach

What is the free water deficit?