Hyponatremia: Difference between revisions

Revision as of 21:39, 9 May 2021

Differential Diagnosis

Pseudohyponatremia from lab error
Translational hyponatremia from mannitol or hyperglycemia
Hypovolemic
- U_Na >20: Renal losses, including mineralocorticoid deficiency
- U_Na <10: Non-renal losses
Euvolemic
- U_osm >100: SIADH, hypothyroidism, glucocorticoid deficiency
- U_osm <100: Primary polydipsia, low solute intake
- U_osm variable: Reset osmostat
Hypervolemic
- U_Na <10: CHD, cirrhosis, nephrosis
- U_Na >20: Renal failure

Investigations

Serum and urine osmolality and electrolytes (prior to treatment)
TSH and AM cortisol

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 == Differential Diagnosis ==
-* [[Pseudohyponatremia]] from lab error
+*[[Pseudohyponatremia]] from lab error
-* [[Translational hyponatremia]] from [[mannitol]] or [[hyperglycemia]]
+*[[Translational hyponatremia]] from [[mannitol]] or [[hyperglycemia]]
-* Hypovolemic
+*Hypovolemic
-** U<sub>Na</sub> &gt;20: Renal losses, including [[mineralocorticoid deficiency]]
+**U<sub>Na</sub> &gt;20: Renal losses, including [[mineralocorticoid deficiency]]
-** U<sub>Na</sub> &lt;10: Non-renal losses
+**U<sub>Na</sub> &lt;10: Non-renal losses
-* Euvolemic
+*Euvolemic
-** U<sub>osm</sub> &gt;100: [[SIADH]], [[hypothyroidism]], [[glucocorticoid deficiency]]
+**U<sub>osm</sub> &gt;100: [[SIADH]], [[hypothyroidism]], [[glucocorticoid deficiency]]
-** U<sub>osm</sub> &lt;100: [[Primary polydipsia]], low solute intake
+**U<sub>osm</sub> &lt;100: [[Primary polydipsia]], low solute intake
-** U<sub>osm</sub> variable: Reset osmostat
+**U<sub>osm</sub> variable: Reset osmostat
-* Hypervolemic
+*Hypervolemic
-** U<sub>Na</sub> &lt;10: CHD, [[cirrhosis]], [[nephrosis]]
+**U<sub>Na</sub> &lt;10: CHD, [[cirrhosis]], [[nephrosis]]
-** U<sub>Na</sub> &gt;20: [[Renal failure]]
+**U<sub>Na</sub> &gt;20: [[Renal failure]]
-== Investigations ==
+==Investigations==
-* Serum and urine osmolality and electrolytes (prior to treatment)
+*Serum and urine osmolality and electrolytes (prior to treatment)
-* TSH and AM cortisol
+*[[TSH]] and AM cortisol
-== Further Reading ==
+==Further Reading==
-* Milionis HJ, Liamis GL, and Elisaf MS. [https://www.cmaj.ca/content/166/8/1056 The hyponatremic patient: a systematic approach to laboratory diagnosis]. ''CMAJ''. 2002;166(8):1056-1062.
+*Milionis HJ, Liamis GL, and Elisaf MS. [https://www.cmaj.ca/content/166/8/1056 The hyponatremic patient: a systematic approach to laboratory diagnosis]. ''CMAJ''. 2002;166(8):1056-1062.
 [[Category:Nephrology]]