Approach to Hyponatremia – Dr Anis

Approach to Hyponatremia – Dr. Anis

Dr. Anis, from the Nephrology department walk us through the physiology of water balance and the diagnostic approach to hyponatremia.

 

Educational Tidbits:

  • General Approach to Hyponatremia
    1. Check serum osms
      • Elevated serum osm: likely hyperglycemia or other osmotic agent
      • Normal serum osm: psuedohyponatremia (hyperproteinemia or hyperlipidemia)
      • Low urine osm: confirmed hypo-osmolar hyponatremia, proceed to b….2
    2. Check urine osms
      1. Urine osms < 100: non ADH dependent
        • Excess fluid intake (psychogenic polydipsia)
        • Decreased solute intake (beer potomania and tea and toast)
      2. Urine osms > 100: ADH is active!, assess volume status
  1. Check volume status
    1. Hypovolemic – use urine Na
      • Urine Na is low: extrarenal volume loss vs decreased volume intake
      • Urine Na is high: renal loss of water (think diuretic)
    2. Hypervolemic – again use urine Na
      • Urine Na is low: CHF, nephrotic syndrome, cirrhosis
      • Urine Na is high: CKD
    3.  Euvolemic
      • SIADH
      • Hypothyroidism
      • Glucocorticoid deficiency
      • Potassium depletion