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
- 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
- Check urine osms
- Urine osms < 100: non ADH dependent
- Excess fluid intake (psychogenic polydipsia)
- Decreased solute intake (beer potomania and tea and toast)
- Urine osms > 100: ADH is active!, assess volume status
- Urine osms < 100: non ADH dependent
- Check serum osms
- Check volume status
- 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)
- Hypervolemic – again use urine Na
- Urine Na is low: CHF, nephrotic syndrome, cirrhosis
- Urine Na is high: CKD
- Euvolemic
- SIADH
- Hypothyroidism
- Glucocorticoid deficiency
- Potassium depletion
- Hypovolemic – use urine Na