Specimen Name Result Units Range
Plasma Sodium 165 mmol/L (135-145)
Potassium 3.2 mmol/L (3.5-5.5)
Chloride 123 mmol/L (100-109)
Bicarbonate 25 mmol/L (22-32)
Anion Gap 20 mmol/L (7-17)
Glucose 4.0 mmol/L (3.8-5.5)
Urea 21.0 mmol/L (2.7-7.2)
Creatinine 210 μmol/L (60-110)
Osmolality 370 mmol/kg (275-295)
Urine Sodium 5 mmol/L (> 20)
Osmolality 900 mmol/kg

Unconscious 46yo female with fever T ≈ 38-40°C
Hyperosmolar Hypernatraemia
  • hypernatraemia & uraemia → likely hypovolaemia (usually H2O loss)
  • inadequate maintenance fluid / IVT
  • extra-renal losses - vomiting, diarrhoea, fistulae, sweating

Diabetes insipidus → hypotonic urine, ∴ unlikely

H2O Deficit Estimation