1. Labs
    • Serum:
      • Electrolytes q1h x6h
      • Osmolality q2h x 6h
      • LFT
      • Serum Uric acid (diuretics)
      • TSH
      • Cortisol (endocrine)
    • Urine:
      • Analysis, Lytes, Urea, Uric Acid (diuretics), Osm, Creat
  2. Treat CNS dysfunction
    • AMS, seizing, neuro findings
      • 3% saline 100mL IV over 10mins (or 2mL/kg), raises Na ~2mmol/L
      • May repeat once (Want more? Repeat Na prior to correction)
    • Consider Head CT if still wonky
  3. Hang tight (avoid osmotic demyelination)
    • Fluid restrict, Foley, Fall precautions and Admit (no more fluids!)
      • Rule of 6’s: Six-a-day for safety (6mEq/L x 24h), Six in six hours for severe symptoms then stop (seizure, AMS)
        • Note: Care when replacing potassium as it will raise Na
      • Only give some NS if truly hypotensive
    • If overcorrected → dDAVP 2mcg IV/sc x1, D5W 6mL/kg over one hour and consult renal


  • Euvolemia
    • SIADH, stress
    • Drug: Thiazide diuretics, Ecstasy, SSRI
    • Endocrine: Hypothyroid, Adrenal insufficiency
    • Exercise-induced (Marathon)
    • Cerebral salt-wasting (subarachnoid)
  • Hypervolemia
    • Renal failure
    • Cardiac failure
    • Cirrhosis
    • Primary polydipsia, beer potomania, tea-toast diet
  • Hypovolemia (Renal vs. Extrarenal)