Pseudohyponatraemia - causes and mechanism (lipids, proteins)
Core concept
- Three different things get called "pseudohyponatraemia" - only one is an artefact
| Serum osmolality | Mechanism | |
|---|---|---|
| True pseudohyponatraemia | NORMAL | Laboratory artefact - solid phase of plasma expanded |
| Translocational (dilutional) | HIGH | Osmotic water shift from ICF -> ECF. Real, but water excess is not the problem |
| True hypotonic hyponatraemia | LOW | Genuine water excess relative to solute |
- *First test in any hyponatraemia is serum osmolality* - it splits the differential in one step
3 more sections, plus exam facts
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