Hyponatremia - Revision history

Aidan: /* Management */

2026-04-06T15:16:50Z

Management

← Older revision		Revision as of 15:16, 6 April 2026
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	== Management ==		== Management ==

	* Depends on cause		* Depends on cause, but generally:
	** Hypovolemic: fluid resuscitation		** Hypovolemic: fluid resuscitation
	** Euvolemic: fluid restriction		** Euvolemic: fluid restriction
	** Hypervolemic: fluid restriction and/or diuretics		** Hypervolemic: fluid restriction and/or diuretics

⚫	* Goal rate of correction in chronic hyponatremia should be 4 to 6 mEq/L in 24 hours ~~(max of 8 mEq)~~ in order to reduce the risk of [[osmotic demyelination syndrome]]
			=== Monitoring ===
		⚫	* Goal rate of correction in chronic hyponatremia should be no more than 8 mEq in 24 hours in order to reduce the risk of [[osmotic demyelination syndrome]]
	* Monitor lytes q6h initially for moderate or severe hyponatremia		* Monitor lytes q6h initially for moderate or severe hyponatremia
			* Monitor urine output: an increased to 100+ mL/h could signal sudden suppression of vasopressin and can cause rapid increase in serum sodium (more common with hypovolemia treated with fluids)
			** Monitor serum sodium q2h until stabilized

	=== Severe Symptoms ===		=== Severe Symptoms ===
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	* Then check serum sodium after 20 minutes, while repeating the infusion		* Then check serum sodium after 20 minutes, while repeating the infusion
	* Repeat process twice or until increase of 5 mmol/L, then stop		* Repeat process twice or until increase of 5 mmol/L, then stop

			=== Hypovolemia ===

			* Restore volume status with either normal saline 0.9% of other balanced crystalloid 0.5-1 mlL/kg/h
			* In cases of shock, rapid fluid resuscitation is probably more important than controlled sodium correction
			* May need close monitoring

			=== Hypervolemia ===

			* Fluid restriction

			=== SIADH ===

			* All patients: fluid restriction
			* Moderate to severe: consider one or both of the following
			** Increasing solute intake with urea 0.25-0.5 g/kg p.o. daily
			** Low-dose loop diuretic plus oral sodium chloride (salt tabs)

			=== Overcorrection ===

			* Should be treated with prompt decrease in serum sodium concentration if >10 mmol/L in first 24 hours or >8 mmol/L in any other 24 hour period
			* Stop current treatment
			* Discuss with Nephrology whether to start D5w 10 mL/kg IV over 1h, or to start desmopressing 2 µg (up to q8h)

	==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.
			*Clinical practice guideline on diagnosis and treatment of hyponatremia. ''Eur J Endocrinol''. 2014;170(3):G1-G47. doi: [https://doi.org/10.1530/EJE-13-1020 10.1530/EJE-13-1020]

	[[Category:Nephrology]]		[[Category:Nephrology]]

Aidan: /* Management */

2026-04-06T15:05:24Z

Management

← Older revision		Revision as of 15:05, 6 April 2026
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	** Hypervolemic: fluid restriction and/or diuretics		** Hypervolemic: fluid restriction and/or diuretics
	* Goal rate of correction in chronic hyponatremia should be 4 to 6 mEq/L in 24 hours (max of 8 mEq) in order to reduce the risk of [[osmotic demyelination syndrome]]		* Goal rate of correction in chronic hyponatremia should be 4 to 6 mEq/L in 24 hours (max of 8 mEq) in order to reduce the risk of [[osmotic demyelination syndrome]]
			* Monitor lytes q6h initially for moderate or severe hyponatremia

	=== Severe Symptoms ===		=== Severe Symptoms ===

Aidan: /* Investigations */

2026-04-06T15:03:56Z

Investigations

Show changes

Aidan at 13:42, 6 April 2026

2026-04-06T13:42:24Z

← Older revision		Revision as of 13:42, 6 April 2026
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	***** Hypouricemia and unchanged FE<sub>urate</sub>: renal salt wasting		***** Hypouricemia and unchanged FE<sub>urate</sub>: renal salt wasting
	**** U<sub>Na</sub> between 20 and 40 mmol/L		**** U<sub>Na</sub> between 20 and 40 mmol/L
	***** Bolus 2L/day normal saline for 2 days and trend sodium		***** Bolus 2 L/day normal saline for 2 days and trend sodium
	***** If S<sub>Na</sub> increases by ≥ 5 mmol/L: hypovolemia		***** If S<sub>Na</sub> increases by ≥ 5 mmol/L: hypovolemia
	***** If S<sub>Na</sub> increases by <5 mmol/L: [[SIADH]] or [[Reset osmostat syndrome\|reset osmostat]]		***** If S<sub>Na</sub> increases by <5 mmol/L: [[SIADH]] or [[Reset osmostat syndrome\|reset osmostat]]
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	* Depends on cause		* Depends on cause
			** Hypovolemic: fluid resuscitation
			** Euvolemic: fluid restriction
			** Hypervolemic: fluid restriction and/or diuretics
	* Goal rate of correction in chronic hyponatremia should be 4 to 6 mEq/L in 24 hours (max of 8 mEq) in order to reduce the risk of [[osmotic demyelination syndrome]]		* Goal rate of correction in chronic hyponatremia should be 4 to 6 mEq/L in 24 hours (max of 8 mEq) in order to reduce the risk of [[osmotic demyelination syndrome]]
			* For patients with hyponatremia (less than 125) with severe symptoms (coma, seizure, respiratory distress) or moderately severe symptoms with risk of (confusion or vomiting) who are at risk of progression, consider hypertonic saline 3% 100-150 mL IV bolus over 10-20 minutes
			** Trend sodium closely
			** Not indicated for asymptomatic or mildly symptomatic chronic hyponatremia

	==Further Reading==		==Further Reading==

Aidan: /* Diagnosis by Lab Criteria */

2024-03-09T20:05:52Z

Diagnosis by Lab Criteria

Aidan at 13:10, 16 September 2023

2023-09-16T13:10:28Z

← Older revision		Revision as of 13:10, 16 September 2023
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	=== Diagnosis by Lab Criteria ===		=== Diagnosis by Lab Criteria ===

	* Serum Na <134?		* Serum Na (S<sub>Na</sub>) <134?
	* Measure serum osmolality and urea level		* Measure serum osmolality (S<sub>osm</sub>) and urea level (S<sub>urea</sub>)
	** ~~Sosm~~ ≥ 280: normotonic/hypertonic		** S<sub>osm</sub> ≥ 280: normotonic/hypertonic
	*** ~~Ddx~~ includes [[pseudohyponatremia]] (from [[hyperlipidemia]], [[hyperparaproteinemia]], etc.), or presence of osmotically active substances ([[glucose]], [[mannitol]])		*** Differential includes [[pseudohyponatremia]] (from [[hyperlipidemia]], [[hyperparaproteinemia]], etc.), or presence of osmotically active substances ([[glucose]], [[mannitol]])
	** ~~Sosm~~ <280 mOsm/kg: true hyponatremia		** S<sub>osm</sub> <280 mOsm/kg: true hyponatremia
	*** Measure urine osmolality		*** Measure urine osmolality (U<sub>osm</sub>)
	*** ~~Uosm~~ <100 mOsm/kg: normal water excretion		*** U<sub>osm</sub> <100 mOsm/kg: normal water excretion
	**** [[Primary polydipsea]] or [[reset osmostat syndrome]]		**** [[Primary polydipsea]] or [[reset osmostat syndrome]]
	*** ~~Uosm~~ ≥ 100 mOsm/kg: impaired water excretion		*** U<sub>osm</sub> ≥ 100 mOsm/kg: impaired water excretion
	**** Exclude [[hypothyroidism]] and [[adrenal insufficiency]] with morning cortisol and TSH		**** Exclude [[hypothyroidism]] and [[adrenal insufficiency]] with morning cortisol and TSH
	**** Measure urine sodium		**** Measure urine sodium (U<sub>Na</sub>)
	**** ~~UNa~~ < 20 mmol/L: [[hypovolemia]], including EABV depletion ([[heart failure]], [[cirrhosis]], [[nephrotic syndrome]])		**** U<sub>Na</sub> < 20 mmol/L: [[hypovolemia]], including EABV depletion ([[heart failure]], [[cirrhosis]], [[nephrotic syndrome]])
	**** ~~UNa~~ > 40 mmol/L: [[SIADH]], [[Reset ostmostat syndrome\|reset ostmostat]], renal salt wasting		**** U<sub>Na</sub> > 40 mmol/L: [[SIADH]], [[Reset ostmostat syndrome\|reset ostmostat]], renal salt wasting
	***** Salt supplementation and water restriction		***** Salt supplementation and water restriction
	***** Normal ~~serum~~ urate and reduced ~~FEurate~~: SIADH		***** Normal S<sub>urate</sub> and reduced FE<sub>urate</sub>: SIADH
	***** Hypouricemia and unchanged ~~FEurate~~: renal salt wasting		***** Hypouricemia and unchanged FE<sub>urate</sub>: renal salt wasting
	**** ~~UNa~~ between 20 and 40 mmol/L		**** U<sub>Na</sub> between 20 and 40 mmol/L
	***** Bolus 2L/day normal saline for 2 days and trend sodium		***** Bolus 2L/day normal saline for 2 days and trend sodium
	***** If ~~SNa~~ increases by ≥ 5 mmol/L: hypovolemia		***** If S<sub>Na</sub> increases by ≥ 5 mmol/L: hypovolemia
	***** If ~~SNa~~ increases by <5 mmol/L: [[SIADH]] or [[Reset ostmostat syndrome\|reset ostmostat]]		***** If S<sub>Na</sub> increases by <5 mmol/L: [[SIADH]] or [[Reset ostmostat syndrome\|reset ostmostat]]
	****** ~~FEurea~~ >55%, ~~serum~~ urate <0.24, and ~~FEurate~~ >10%: SIADH		****** FE<sub>urea</sub> >55%, S<sub>urate</sub> <0.24, and FE<sub>urate</sub> >10%: SIADH
	****** Oral or IV water-loading test: [[Reset ostmostat syndrome\|reset ostmostat]]		****** Oral or IV water-loading test: [[Reset ostmostat syndrome\|reset ostmostat]]

			== Management ==

			* Depends on cause
			* Goal rate of correction in chronic hyponatremia should be 4 to 6 mEq/L in 24 hours (max of 8 mEq) in order to reduce the risk of [[osmotic demyelination syndrome]]

	==Further Reading==		==Further Reading==

Aidan at 16:32, 6 May 2023

2023-05-06T16:32:45Z

← Older revision		Revision as of 16:32, 6 May 2023
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			== Etiologies ==

			* Medications: [[thiazide]] and thiazide-type diuretics, [[mannitol]], [[IVIG]], [[desmopressin]] (dDAVP), [[ecstasy]] (methylenedioxymethamphetamine), and some antidepressants, antiepileptics, and antipsychotics

	==Differential Diagnosis==		==Differential Diagnosis==

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	* Measure serum osmolality and urea level		* Measure serum osmolality and urea level
	** Sosm ≥ 280: normotonic/hypertonic		** Sosm ≥ 280: normotonic/hypertonic
	*** Ddx includes pseudohyponatremia (from hyperlipidemia, hyperparaproteinemia, etc.), or presence of osmotically active substances (glucose, mannitol)		*** Ddx includes [[pseudohyponatremia]] (from [[hyperlipidemia]], [[hyperparaproteinemia]], etc.), or presence of osmotically active substances ([[glucose]], [[mannitol]])
	** Sosm <280 mOsm/kg: true hyponatremia		** Sosm <280 mOsm/kg: true hyponatremia
	*** Measure urine osmolality		*** Measure urine osmolality
	*** Uosm <100 mOsm/kg: normal water excretion		*** Uosm <100 mOsm/kg: normal water excretion
	**** Primary ~~polydipsiea~~ or reset osmostat syndrome		**** [[Primary polydipsea]] or [[reset osmostat syndrome]]
	*** Uosm ≥ 100 mOsm/kg: impaired water excretion		*** Uosm ≥ 100 mOsm/kg: impaired water excretion
	**** Exclude hypothyroidism and adrenal insufficiency with morning cortisol and TSH		**** Exclude [[hypothyroidism]] and [[adrenal insufficiency]] with morning cortisol and TSH
	**** Measure urine sodium		**** Measure urine sodium
	**** UNa < 20 mmol/L: hypovolemia, including EABV depletion (heart failure, cirrhosis, nephrotic syndrome)		**** UNa < 20 mmol/L: [[hypovolemia]], including EABV depletion ([[heart failure]], [[cirrhosis]], [[nephrotic syndrome]])
	**** UNa > 40 mmol/L: SIADH, reset ostmostat, renal salt wasting		**** UNa > 40 mmol/L: [[SIADH]], [[Reset ostmostat syndrome\|reset ostmostat]], renal salt wasting
	***** Salt supplementation and water restriction		***** Salt supplementation and water restriction
	***** Normal serum urate and reduced FEurate: SIADH		***** Normal serum urate and reduced FEurate: SIADH
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	***** Bolus 2L/day normal saline for 2 days and trend sodium		***** Bolus 2L/day normal saline for 2 days and trend sodium
	***** If SNa increases by ≥ 5 mmol/L: hypovolemia		***** If SNa increases by ≥ 5 mmol/L: hypovolemia
	***** If SNa increases by <5 mmol/L: SIADH or reset ostmostat		***** If SNa increases by <5 mmol/L: [[SIADH]] or [[Reset ostmostat syndrome\|reset ostmostat]]
	****** FEurea >55%, serum urate <0.24, and FEurate >10%: SIADH		****** FEurea >55%, serum urate <0.24, and FEurate >10%: SIADH
	****** Oral or IV water-loading test: ~~reset~~ ~~osmostat~~ syndrome		****** Oral or IV water-loading test: [[Reset ostmostat syndrome\|reset ostmostat]]

	==Further Reading==		==Further Reading==

Aidan: Text replacement - ">=" to "≥"

2022-09-30T15:31:00Z

Text replacement - ">=" to "≥"

← Older revision		Revision as of 15:31, 30 September 2022
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	* Serum Na <134?		* Serum Na <134?
	* Measure serum osmolality and urea level		* Measure serum osmolality and urea level
	** Sosm >= 280: normotonic/hypertonic		** Sosm ≥ 280: normotonic/hypertonic
	*** Ddx includes pseudohyponatremia (from hyperlipidemia, hyperparaproteinemia, etc.), or presence of osmotically active substances (glucose, mannitol)		*** Ddx includes pseudohyponatremia (from hyperlipidemia, hyperparaproteinemia, etc.), or presence of osmotically active substances (glucose, mannitol)
	** Sosm <280 mOsm/kg: true hyponatremia		** Sosm <280 mOsm/kg: true hyponatremia
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	*** Uosm <100 mOsm/kg: normal water excretion		*** Uosm <100 mOsm/kg: normal water excretion
	**** Primary polydipsiea or reset osmostat syndrome		**** Primary polydipsiea or reset osmostat syndrome
	*** Uosm >= 100 mOsm/kg: impaired water excretion		*** Uosm ≥ 100 mOsm/kg: impaired water excretion
	**** Exclude hypothyroidism and adrenal insufficiency with morning cortisol and TSH		**** Exclude hypothyroidism and adrenal insufficiency with morning cortisol and TSH
	**** Measure urine sodium		**** Measure urine sodium
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	**** UNa between 20 and 40 mmol/L		**** UNa between 20 and 40 mmol/L
	***** Bolus 2L/day normal saline for 2 days and trend sodium		***** Bolus 2L/day normal saline for 2 days and trend sodium
	***** If SNa increases by >= 5 mmol/L: hypovolemia		***** If SNa increases by ≥ 5 mmol/L: hypovolemia
	***** If SNa increases by <5 mmol/L: SIADH or reset ostmostat		***** If SNa increases by <5 mmol/L: SIADH or reset ostmostat
	****** FEurea >55%, serum urate <0.24, and FEurate >10%: SIADH		****** FEurea >55%, serum urate <0.24, and FEurate >10%: SIADH

Aidan: /* Investigations */

2021-05-10T16:22:17Z

Investigations

@@ Line 1: / Line 1: @@
-== Differential Diagnosis ==
+==Differential Diagnosis==
 *[[Pseudohyponatremia]] from lab error
@@ Line 18: / Line 18: @@
 *Serum and urine osmolality and electrolytes (prior to treatment)
 *[[TSH]] and AM cortisol
 ==Further Reading==

Aidan at 01:39, 10 May 2021

2021-05-10T01:39:48Z

← Older revision		Revision as of 01:39, 10 May 2021
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	== Differential Diagnosis ==		== 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> >20: Renal losses, including [[mineralocorticoid deficiency]]		**U<sub>Na</sub> >20: Renal losses, including [[mineralocorticoid deficiency]]
	** U<sub>Na</sub> <10: Non-renal losses		**U<sub>Na</sub> <10: Non-renal losses
	* Euvolemic		*Euvolemic
	** U<sub>osm</sub> >100: [[SIADH]], [[hypothyroidism]], [[glucocorticoid deficiency]]		**U<sub>osm</sub> >100: [[SIADH]], [[hypothyroidism]], [[glucocorticoid deficiency]]
	** U<sub>osm</sub> <100: [[Primary polydipsia]], low solute intake		**U<sub>osm</sub> <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> <10: CHD, [[cirrhosis]], [[nephrosis]]		**U<sub>Na</sub> <10: CHD, [[cirrhosis]], [[nephrosis]]
	** U<sub>Na</sub> >20: [[Renal failure]]		**U<sub>Na</sub> >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]]		[[Category:Nephrology]]

← Older revision		Revision as of 20:05, 9 March 2024
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	*** Measure urine osmolality (U<sub>osm</sub>)		*** Measure urine osmolality (U<sub>osm</sub>)
	*** U<sub>osm</sub> <100 mOsm/kg: normal water excretion		*** U<sub>osm</sub> <100 mOsm/kg: normal water excretion
	**** [[Primary ~~polydipsea~~]] or [[reset osmostat syndrome]]		**** [[Primary polydipsia]] or [[reset osmostat syndrome]]
	*** U<sub>osm</sub> ≥ 100 mOsm/kg: impaired water excretion		*** U<sub>osm</sub> ≥ 100 mOsm/kg: impaired water excretion
	**** Exclude [[hypothyroidism]] and [[adrenal insufficiency]] with morning cortisol and TSH		**** Exclude [[hypothyroidism]] and [[adrenal insufficiency]] with morning cortisol and TSH
	**** Measure urine sodium (U<sub>Na</sub>)		**** Measure urine sodium (U<sub>Na</sub>)
	**** U<sub>Na</sub> < 20 mmol/L: [[hypovolemia]], including EABV depletion ([[heart failure]], [[cirrhosis]], [[nephrotic syndrome]])		**** U<sub>Na</sub> < 20 mmol/L: [[hypovolemia]], including EABV depletion ([[heart failure]], [[cirrhosis]], [[nephrotic syndrome]])
	**** U<sub>Na</sub> > 40 mmol/L: [[SIADH]], [[Reset ~~ostmostat~~ syndrome\|reset ~~ostmostat~~]], renal salt wasting		**** U<sub>Na</sub> > 40 mmol/L: [[SIADH]], [[Reset osmostat syndrome\|reset osmostat]], renal salt wasting
	***** Salt supplementation and water restriction		***** Salt supplementation and water restriction
	***** Normal S<sub>urate</sub> and reduced FE<sub>urate</sub>: SIADH		***** Normal S<sub>urate</sub> and reduced FE<sub>urate</sub>: SIADH
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	***** Bolus 2L/day normal saline for 2 days and trend sodium		***** Bolus 2L/day normal saline for 2 days and trend sodium
	***** If S<sub>Na</sub> increases by ≥ 5 mmol/L: hypovolemia		***** If S<sub>Na</sub> increases by ≥ 5 mmol/L: hypovolemia
	***** If S<sub>Na</sub> increases by <5 mmol/L: [[SIADH]] or [[Reset ~~ostmostat~~ syndrome\|reset ~~ostmostat~~]]		***** If S<sub>Na</sub> increases by <5 mmol/L: [[SIADH]] or [[Reset osmostat syndrome\|reset osmostat]]
	****** FE<sub>urea</sub> >55%, S<sub>urate</sub> <0.24, and FE<sub>urate</sub> >10%: SIADH		****** FE<sub>urea</sub> >55%, S<sub>urate</sub> <0.24, and FE<sub>urate</sub> >10%: SIADH
	****** Oral or IV water-loading test: [[Reset ~~ostmostat~~ syndrome\|reset ~~ostmostat~~]]		****** Oral or IV water-loading test: [[Reset osmostat syndrome\|reset osmostat]]

	== Management ==		== Management ==