Hyponatremia diagnostic study of choice: Difference between revisions

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{{CMG}}; {{AE}} {{Saeedeh}}
{{CMG}}; {{AE}} {{Saeedeh}}
== Overview ==
== Overview ==
* The page name should be '''"[Disease name] diagnostic study of choice"''', with only the first letter of the title capitalized. Note that the page is called "Diagnostic study of choice."
 
* '''Goal:'''
Best diagnostic test to measure hyponatremia, serum sodium < 135 mEq/L, is direct ion-specific electrode potentiometry. Other tests are associated with false results in certain conditions.
**To describe the most efficient/sensitive/specific test that is utilized for diagnosis of [disease name].
**To describe the gold standard test for the diagnosis of [disease name].
**To describe the diagnostic criteria, which may be based on clinical findings, physical exam signs, pathological findings, lab findings, findings on imaging, or even findings that exclude other diseases.
* As with all microchapter pages linking to the main page, at the top of the edit box put <nowiki>{{CMG}}</nowiki>, your name template, and the microchapter navigation template you created at the beginning.
* Remember to create links within WikiDoc by placing <nowiki>[[square brackets]]</nowiki> around key words which you want to link to other pages. Make sure you makes your links as specific as possible. For example, if a sentence contained the phrase anterior spinal artery syndrome, the link should be to [[anterior spinal artery syndrome]] not [[anterior]] or [[artery]] or [[syndrome]].  For more information on how to create links, click [[here]].
* Remember to follow the same format and capitalization of letters as outlined in the template below.
* You should include the name of the disease in the first sentence of every subsection.


Different etiologies of hyponatremia are differentiated based on serum osmolality, urine osmolality, and urine sodium.


===== Template statements =====
To see the different caused of hyponatremia, click [[Hyponatremia causes#Causes|here]].


=== Gold standard/Study of choice: ===
== Study of choice ==
* [Name of the investigation] is the gold standard test for the diagnosis of [disease name].
* The following result of [gold standard test] is confirmatory of [disease name]:
** Result 1
** Result 2
* The [name of the investigation] should be performed when:
** The patient presented with symptoms/signs 1. 2, 3.
** A positive [test] is detected in the patient.
* [Name of the investigation] is the gold standard test for the diagnosis of [disease name].
* The diagnostic study of choice for [disease name] is [name of the investigation].
* There is no single diagnostic study of choice for the diagnosis of [disease name].
* There is no single diagnostic study of choice for the diagnosis of [disease name], but [disease name] can be diagnosed based on [name of the investigation 1] and [name of the investigation 2].
* [Disease name] is mainly diagnosed based on clinical presentation.
* Investigations:
** Among patients who present with clinical signs of [disease name], the [investigation name] is the most specific test for the diagnosis.
** Among patients who present with clinical signs of [disease name], the [investigation name] is the most sensitive test for diagnosis.
** Among patients who present with clinical signs of [disease name], the [investigation name] is the most efficient test for diagnosis.


==== The comparison table for diagnostic studies of choice for [disease name] ====
Previously, there were two methods to determine serum sodium <ref>{{Cite journal
{|
|- style="background: #4479BA; color: #FFFFFF; text-align: center;"
! style="background: #FFFFFF; color: #FFFFFF; text-align: center;" |
! style="background: #4479BA; color: #FFFFFF; text-align: center;" |Sensitivity
! style="background: #4479BA; color: #FFFFFF; text-align: center;" |Specificity
|-
! style="background: #696969; color: #FFFFFF; text-align: center;" |Test 1
| style="background: #DCDCDC; padding: 5px; text-align: center;" |✔
| style="background: #DCDCDC; padding: 5px; text-align: center;" |...%
|-
! style="background: #696969; color: #FFFFFF; text-align: center;" |Test 2
| style="background: #DCDCDC; padding: 5px; text-align: center;" |...%
| style="background: #DCDCDC; padding: 5px; text-align: center;" |✔
|}
<small> ✔= The best test based on the feature </small>


===== Diagnostic results =====
| author = [[F. S. Apple]], [[D. D. Koch]], [[S. Graves]] & [[J. H. Ladenson]]
The following result of [investigation name] is confirmatory of [disease name]:
* Result 1
* Result 2


===== Sequence of Diagnostic Studies =====
| title = Relationship between the direct-potentiometric and flame-photometric measurement of sodium in the blood
The [name of investigation] should be performed when:
* The patient presented with symptoms/signs 1, 2, and 3 as the first step of diagnosis.
* A positive [test] is detected in the patient, to confirm the diagnosis.


=== Diagnostic Approach to Hyponatremia ===
| journal = [[Clinical chemistry]]


| volume = 28
| issue = 9
| pages = 1931–1935
| year = 1982
| month = September
| pmid = 7127808
}}</ref>   :
* Flame emission spectrophotometry
* Ion-specific electrode (ISE) potentiometry
ISE potentiometry has two different subtypes: Direct (undiluted) and indirect (diluted).
'''Direct ISE''' measures plasma sodium directly from a whole-blood sample and it's not associated with either pseudohyponatremia or pseudonormonatremia.
FES or indirect ISE requires sample dilution before assay  <ref name="HussainAhmad20152">{{cite journal|last2=Ahmad|first2=Zahid|last3=Garg|first3=Abhimanyu|year=2015|title=Extreme hypercholesterolemia presenting with pseudohyponatremia - a case report and review of the literature|journal=Journal of Clinical Lipidology|volume=9|issue=2|pages=260–264|doi=10.1016/j.jacl.2014.11.007|issn=19332874|last1=Hussain|first1=Iram}}</ref> and both are associated with pseudohyponatremia.
===== <big>Sequence of Diagnostic Studies</big> =====
The most diagnostic studies which can help to diagnose and differentiate between different causes of hyponatremia are: Serum osmolality, urine osmolality, urine sodium.
<br>
'''Biochemical evaluation for finding the etiologies of hyponatremia :'''
* Serum sodium
* Serum osmolality
* [[Serum potassium]]
* Serum chloride
* [[Serum creatinine]]
* Serum other solutes
* Serum [[urea]]
* Blood Glucose
* Total protein and albumin
* Serum [[lipids]]
* Total bilirubin and direct bilirubin
* Red and white cell blood count
* Serum [[Cortisol level|cortisol]]
* Adrenocorticotropine hormone
* [[ADH|ADH level]]
* [[TSH]]
* Urine sodium
* Urine chloride
* [[Urine osmolality]]
* Urine for other solutes
* Fraction excretion of sodium
* Calculated [[GFR]]
<br>
For differential diagnosis click [[Hyponatremia differential diagnosis|here]].
<br>
=== Diagnostic Approach to Hyponatremia <ref name="AdroguéMadias2014">{{cite journal|last1=Adrogué|first1=Horacio J.|last2=Madias|first2=Nicolaos E.|title=Diagnosis and Treatment of Hyponatremia|journal=American Journal of Kidney Diseases|volume=64|issue=5|year=2014|pages=681–684|issn=02726386|doi=10.1053/j.ajkd.2014.06.001}}</ref> <ref name="SahaySahay2014">{{cite journal|last1=Sahay|first1=Manisha|last2=Sahay|first2=Rakesh|title=Hyponatremia: A practical approach|journal=Indian Journal of Endocrinology and Metabolism|volume=18|issue=6|year=2014|pages=760|issn=2230-8210|doi=10.4103/2230-8210.141320}}</ref> <ref>{{Cite journal
| author = [[E. J. Hoorn]], [[M. L. Halperin]] & [[R. Zietse]]
| title = Diagnostic approach to a patient with hyponatraemia: traditional versus physiology-based options
| journal = [[QJM : monthly journal of the Association of Physicians]]
| volume = 98
| issue = 7
| pages = 529–540
| year = 2005
| month = July
| doi = 10.1093/qjmed/hci081
| pmid = 15955797
}}</ref> ===
<small>
{{familytree/start |summary=Sample 6}}
{{familytree/start |summary=Sample 6}}
{{familytree | | | | | | | | A01 |A01=Serum sodium < 135 mEq/L}}  
{{familytree | | | | | | | | A01 |A01=Serum sodium < 135 mEq/L}}  
{{familytree | | | | | | | | |!| | | | | | | }}
{{familytree | | | | | | | | |!| | | | | | | }}
{{familytree |boxstyle=text-align: left; | | | | | | | | A02 | | | | | |A02=Check for '''Psuedohyponatremia'''<br> • Check for '''Hyperglycemia'''<br>• Check for '''Hyperproteinemia'''<br>• Check for '''hyperlipidemia'''<br>• Check for other '''solutes in serum'''<br>• Check for sign of '''Jaundice'''<br>• Check for history of '''Operation'''}}
{{familytree | | | | | | | | A02 | | | | | |A02=<table><tr><th>Psuedohyponatremia</th></tr><tr><td> • Check for '''[[hyperglycemia]]'''<br>• Check for '''[[hyperproteinemia]]'''<br>• Check for '''[[hyperlipidemia]]'''<br>• Check for other '''solutes in serum'''<br>• Check for sign of '''[[Jaundice]]'''<br>• Check for history of '''operation'''</td></tr></table>}}
{{familytree | | | | | | | | |!| | | | | | | }}
{{familytree | | | | | | | | |!| | | | | | | }}
{{familytree | | | | | | | | B01 | | | | | |B01=Measure '''serum Osmolality'''}}
{{familytree | | | | | | | | B01 | | | | | |B01=Measure '''[[serum Osmolality]]'''}}
{{familytree | | | | |,|-|-|-|^|-|-|-|-|.| | | }}
{{familytree | | | |,|-|-|-|-|^|-|-|-|-|.| | | }}
{{familytree | | | B01 | | | | | | | | B02 | | |B01=Low < 280 momol/kg |B02=Normal or High}}
{{familytree | | | B01 | | | | | | | | B02 | | |B01='''Low < 280 momol/kg''' |B02='''Normal or High<br>> 280 momol/kg'''}}
{{familytree | | | |!| | | | | | | | | |!| }}
{{familytree | | | |!| | | | | | | | | |!| }}
{{familytree | | | C01 | | | | | | | | C02 |C01='''Hypotonic Hyponatremia'''|C02='''Isoosmolar or Hyperosmolar hyponatremia'''}}
{{familytree | | | C01 | | | | | | | | C02 |C01='''Hypotonic Hyponatremia'''|C02='''Isoosmolar or Hyperosmolar hyponatremia'''}}
{{familytree | | | |!| | | | | | | | | |!| }}
{{familytree | | | |!| | | | | | | | | |!| }}
{{familytree |boxstyle=text-align: left; | | | D01 |-|-| D02 | | | D03 |D01=• Low GFR<br>• History of Thiazide use|D02=Yes|D03=• Post TURP or hysteroscopy (Glycine, Sorbitol)<br>• Direct sodium by direct potentiometry if normal measure total protein and lipid }}
{{familytree | | | D01 |-|-|-|.| | | | D03 |D01=<div style="text-align:left;border-left: 6px" > • Low GFR<br>• History of [[Thiazide]] use</div>|D03=• Post TURP or hysteroscopy (Glycine, Sorbitol)<br>• Check direct sodium by direct potentiometry if normal measure total protein and lipid|boxstyle D01=text-align: left; | }}
{{familytree | | | |!| | | | |!| | | | | | |}}
{{familytree | | | |!| | | | |!| | | | | | |}}
{{familytree |boxstyle=text-align: left; | | | E01 | | | E02 | | | | |E01=No|E02=• Renal failure<br>• Thiazide induce hyponatremia<br>|}}  
{{familytree | | | E01 | | | D02 |-| E02 |E01=No||D02=Yes|E02=• [[Renal failure]]<br>• [[Thiazide]] induce hyponatremia<br>}}  
{{familytree | |,|-|^|-|-|-|.| | | | | | | | |}}
{{familytree | |,|-|^|-|-|-|.| | | | | | | | |}}
{{familytree | | F01 | | | F02 | | | | | | | |F01=Patients with '''edema'''<br>(pulmonary, peripheral), ascites|F02=Signs and Symptoms of '''hypovolemia'''<br>(↓ BP, Orthostatic hypotension)|}}
{{familytree | F01 | | | | F02 | | | | | | | |F01=Patients with '''[[edema]]'''<br>(pulmonary, peripheral),[[ascites]]|F02=Signs and Symptoms of '''[[hypovolemia]]'''<br>(↓ BP, [[Orthostatic]] hypotension)}}
{{familytree | | |!| | | | |!| | | | | | |}}
{{familytree | G01 | | | | |!| | | | | | | | |G01=[[Heart failure]]<br> [[Cirrhosis]]|}}
{{familytree | | G01 | | | |!| | | | |,| G02 |G01=Heart failure<br> Cirrhosis|G02=Low Less<25 mEq/L<br>'''Hypovolemic Hyponatremia'''<br>Extra renal loss(Gastrointestinal losses, Diuretics, Third space losses)}}
{{familytree | | | | | | | |!| | | | |,| G02 |G02=<table><tr><th>Less < 25 mEq/L<br>Hypovolemic Hyponatremia</th></tr><tr><td>Extra renal loss<br>Gastrointestinal losses, Diuretics, [[third sapcing of fluid|Third space losses]]</td></tr></table>}}
{{familytree | | | | | | | |!| | | | |!| |}}
{{familytree | | | | | | | |!| | | | |!| |}}
{{familytree | | | |,|-|-|-|^|-|-|.| |!| | |}}
{{familytree | | | |,|-|-|-|^|-|-|.| |!| | |}}
{{familytree | | | J01 | | | | | J02 |!| | | |J01=No|J02=Yes}}
{{familytree | | | J01 | | | | | J02 |!| | | |J01=No|J02=Yes}}
{{familytree | | | |!| | | | | | |!| |!| |K01=mio}}
{{familytree | | | |!| | | | | | |!| |!| | | |}}
{{familytree | | | H01 | | | | | H02 |+| H03 | |H01=Measure '''urine sodium''' and '''serum osmolality'''|H02=Measure '''urine sodium'''|H03=25 to 40 mEq/L<br>Infuse Isotonic saline<br>1 L over 1 hour<br>Remeasure urine sodium}}
{{familytree | | | H01 | | | | | H02 |+| H03 | |H01=Measure '''[[urine sodium]]''' and '''[[serum osmolality]]'''|H02=Measure '''[[urine sodium]]'''|H03=<table><tr><th>25 to 40 mEq/L</th></tr><tr><td>Infuse Isotonic saline 1 liter over 1 hour<br>Remeasure urine sodium</td></tr></table>}}
{{familytree | | | |!| | | | | | | | |!| }}
{{familytree | | | |!| | | | | | | | |!| | | |}}
{{familytree | | | I01 |-| I02 | | | |`| I03 |I01=Urine osmolality<100|I02=Yes|I03=Hight >40 mEq/L<br>'''Hypovolemic Hyponatremia'''<br>Renal loss}}
{{familytree | | | I01 |-|-|.| | | | |`| I03 |I01='''Urine <sub>Osm</sub> < 100'''|I03=<table><tr><th>Hight > 40 mEq/L<br>Hypovolemic Hyponatremia</th></tr><tr><td>Renal loss</td></tr></table>}}
{{familytree | | | |!| | | |!| | | | | | | | }}
{{familytree | | | |!| | | I02 | | | | | |!| |I02=Yes|}}
{{familytree | | | G01 | | G02 |-| G03 | | | |G01=No|G02=Urine osmolality measured '''After therapy initiated'''|G03=Yes}}
{{familytree | | | G01 | | G02 |-| G03 | |)| G04 |G01=No|G02='''[[Urine osmolality]]''' measured '''After therapy initiated'''|G03=Yes|G04=Use of diuretics}}
{{familytree | | | |!| | | |!| | | |!|}}  
{{familytree | | | |!| | | |!| | | |!| | |!| |}}  
{{familytree | | | L01 | | L02 | | L03 |L01=Urine sodium>40|L02=No|L03=Recovery from one of the followings:<br>• Mild hypovolemia(Patients given isotonic fluids<br>• Hypopituitarism(Patients given glucocorticoids))}}
{{familytree | | | |!| | | |!| | | L03 | |)| L04 |L03=<table><tr><th>Recovery from one of the followings:</th></tr><tr><td>• Mild hypovolemia(Patients given isotonic fluids<br>• [[Hypopituitarism]]<br>(Patients given [[glucocorticoids]]))</td></tr></table>|L04='''Low [[cortisol]],<br>Positive [[ACTH]] stimulation'''<br>Primary [[adrenal insufficiency]]}}
{{familytree | |,|-|^|-|.| |!| | | | | | | |}}
{{Family tree| | | L01 | | L02 | | | | | |!| | | |L01='''Urine <sub>Na</sub> > 40 mEq/L'''|L02=No}}
{{familytree | P01 | | P02 |!| | | | | | | | | |P01=No|P02=Yes}}
{{familytree | |,|-|^|-|.| |!| | | | | | |`| P03 |P03='''Head injury/surgery'''<br>[[Cerebral salt-wasting syndrome|Cerebral-salt wasting]]}}
{{familytree | |!| | | |!| |!| | | | | | | | | }}
{{familytree | P01 | | P02 |!| | | | | | | | | | |P01=No|P02=Yes}}
{{familytree | |!| | | |!| Q01 | | | | | | | | |Q01=Patient with rapid water consumption}}
{{familytree | |!| | | |!| |!| | | | | | | | | | }}
{{familytree | R01 | | |!| |!| | | | | | | | | |R01=Ensure that sodium intake> 150 mEq/L over next 24 hours(infuse 1 liter of isotonic fluid over one or more hour)}}
{{familytree | |!| | | |!| Q01 |-|-|-|-|.| | | |Q01=Patient with '''rapid water consumption'''}}
{{familytree | R01 | | |!| |!| | | | | |!| | | |R01=Ensure that sodium intake > 150 mEq/L over next 24 hours (infuse 1 liter of isotonic fluid over one or more hour)}}
{{familytree | S01 | | |!| |`| R02 | | Q02 | | |R02=No|Q02=Yes|S01=Remeasure urine osmolality and sodium|}}
{{familytree | |!| | | |!| | | |!| | | |!| | | |}}
{{familytree | |!| | | |!| | | R03 | | Q03 | | |R03=<table><tr><th>High-fluid<br>low-protein diet including:</th></tr><tr><td>• [[Beer potomania]]<br>• Tea and toast diet</td></tr></table>|Q03=<table><tr><th>Water intoxication:</th><tr><tr><td>• [[Psychosis]]<br>• Endurance activity (Marathone)<br>• [[Ecstasy]] use</td></tr></table>}}
{{familytree | |)| Z02 |!| | | | | | | | | | | |Z02='''Urine <sub>Na</sub> >40 or<br>Urine <sub>Osm</sub> > 100'''}}
{{familytree | |!| |!| |!| | | | | | | | | | | |}}
{{familytree | Z01 |!| |!| | | | | | | | | | | |Z01='''Urine <sub>Na</sub> < 40 or<br> Urine <sub>Osm</sub> < 100'''}}
{{familytree | T01 |!| |!| | | | | | | | | | | |T01='''Hypovolemic Hyponatremia'''|}}
{{familytree | | | |`| T02 | | | | | | | | | | | |T02=<table><tr><th>Check for:</th></tr><tr><td>• Glucocorticoid deficiency with<br>[[Cortisol]] level and [[ACTH]] stimulationand <br>• [[Hypothyroidism]] with TSH</td></tr></table>}}
{{familytree | | | | | |!| | | | | | | | | | | |}}
{{familytree | | | | | X01 | | | | | | | | | | |X01= check '''morning [[cortisol]]''' and<br>'''[[ACTH]] stimulation test'''}}
{{familytree | | | |,|-|^|-|.| | | | | | | |}}
{{familytree | | | C01 | | C02 | | | | | | | |C01=Yes|C02=No}}
{{familytree | | | |!| | | |!| | |}}
{{familytree | | | V01 | | V02 | | | |V01=Glucocorticoid deficiency|V02=Elevated '''[[TSH]]'''}}
{{familytree | | | | | |,|-|^|-|-|.| | | | |}}
{{familytree | | | | | B01 | | | B02 | | | | | |B01=No|B02=Yes}}
{{familytree | | | | | |!| | | | |!| | | | | | |}}
{{familytree | | | | | N01 | | | N02 | | | | | |N01=SIAD<br>Nephrogenic [[SIADH|SIAD]]<br>Reset [[Osmostat]]|N02=Severe [[Hypothyroidism]]}}
{{familytree | | | | | |!| | | | | | | | | | |}}
{{familytree | | | | | M01 | | | | | | | | | |M01=Evaluate underlying [[Hyponatremia causes#Causes|etiology]]}}
{{familytree/end}}
{{familytree/end}}
 
</small>
 
 
 
 
 
 
 
 
* Here you should describe the details of the diagnostic criteria.
*Always mention the name of the criteria/definition you are about to list (e.g. modified Duke criteria for the diagnosis of endocarditis / 3rd universal definition of MI) and cite the primary source of where this criteria/definition is found.
*Although not necessary, it is recommended that you include the criteria in a table. Make sure you always cite the source of the content and whether the table has been adapted from another source.
*Be very clear as to the number of criteria (or threshold) that needs to be met out of the total number of criteria.
*Distinguish criteria based on their nature (e.g. clinical criteria / pathological criteria/ imaging criteria) before discussing them in details.
*To view an example (endocarditis diagnostic criteria), click [[Endocarditis diagnosis|here]]
*If relevant, add additional information that might help the reader distinguish various criteria or the evolution of criteria (e.g. original criteria vs. modified criteria).
*You may also add information about the sensitivity and specificity of the criteria, the pre-test probability, and other figures that may help the reader understand how valuable the criteria are clinically.
* [Disease name] is mainly diagnosed based on clinical presentation. There are no established criteria for the diagnosis of [disease name].
* There is no single diagnostic study of choice for [disease name], though [disease name] may be diagnosed based on [name of criteria] established by [...].
 
* The diagnosis of [disease name] is made when at least [number] of the following [number] diagnostic criteria are met: [criterion 1], [criterion 2], [criterion 3], and [criterion 4].
* The diagnosis of [disease name] is based on the [criteria name] criteria, which includes [criterion 1], [criterion 2], and [criterion 3].
 
* [Disease name] may be diagnosed at any time if one or more of the following criteria are met:
** Criteria 1
** Criteria 2
** Criteria 3
 
IF there are clear, established diagnostic criteria:
*The diagnosis of [disease name] is made when at least [number] of the following [number] diagnostic criteria are met: [criterion 1], [criterion 2], [criterion 3], and [criterion 4].
*The diagnosis of [disease name] is based on the [criteria name] criteria, which include [criterion 1], [criterion 2], and [criterion 3].
*The diagnosis of [disease name] is based on the [definition name] definition, which includes [criterion 1], [criterion 2], and [criterion 3].
IF there are no established diagnostic criteria: 
*There are no established criteria for the diagnosis of [disease name].


==References==
==References==

Latest revision as of 20:31, 2 July 2021

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Saeedeh Kowsarnia M.D.[2]

Overview

Best diagnostic test to measure hyponatremia, serum sodium < 135 mEq/L, is direct ion-specific electrode potentiometry. Other tests are associated with false results in certain conditions.

Different etiologies of hyponatremia are differentiated based on serum osmolality, urine osmolality, and urine sodium.

To see the different caused of hyponatremia, click here.

Study of choice

Previously, there were two methods to determine serum sodium [1]   :

  • Flame emission spectrophotometry
  • Ion-specific electrode (ISE) potentiometry

ISE potentiometry has two different subtypes: Direct (undiluted) and indirect (diluted).

Direct ISE measures plasma sodium directly from a whole-blood sample and it's not associated with either pseudohyponatremia or pseudonormonatremia.

FES or indirect ISE requires sample dilution before assay [2] and both are associated with pseudohyponatremia.

Sequence of Diagnostic Studies

The most diagnostic studies which can help to diagnose and differentiate between different causes of hyponatremia are: Serum osmolality, urine osmolality, urine sodium.


Biochemical evaluation for finding the etiologies of hyponatremia :

  • Serum sodium
  • Serum osmolality
  • Serum potassium
  • Serum chloride
  • Serum creatinine
  • Serum other solutes
  • Serum urea
  • Blood Glucose
  • Total protein and albumin
  • Serum lipids
  • Total bilirubin and direct bilirubin
  • Red and white cell blood count
  • Serum cortisol
  • Adrenocorticotropine hormone
  • ADH level
  • TSH
  • Urine sodium
  • Urine chloride
  • Urine osmolality
  • Urine for other solutes
  • Fraction excretion of sodium
  • Calculated GFR


For differential diagnosis click here.

Diagnostic Approach to Hyponatremia [3] [4] [5]

 
 
 
 
 
 
 
Serum sodium < 135 mEq/L
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Psuedohyponatremia
• Check for hyperglycemia
• Check for hyperproteinemia
• Check for hyperlipidemia
• Check for other solutes in serum
• Check for sign of Jaundice
• Check for history of operation
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Measure serum Osmolality
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Low < 280 momol/kg
 
 
 
 
 
 
 
Normal or High
> 280 momol/kg
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Hypotonic Hyponatremia
 
 
 
 
 
 
 
Isoosmolar or Hyperosmolar hyponatremia
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
• Low GFR
• History of Thiazide use
 
 
 
 
 
 
 
 
• Post TURP or hysteroscopy (Glycine, Sorbitol)
• Check direct sodium by direct potentiometry if normal measure total protein and lipid
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
No
 
 
Yes
 
Renal failure
Thiazide induce hyponatremia
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Patients with edema
(pulmonary, peripheral),ascites
 
 
 
Signs and Symptoms of hypovolemia
(↓ BP, Orthostatic hypotension)
 
 
 
 
 
 
 
Heart failure
Cirrhosis
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Less < 25 mEq/L
Hypovolemic Hyponatremia
• Extra renal loss
Gastrointestinal losses, Diuretics, Third space losses
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
No
 
 
 
 
Yes
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Measure urine sodium and serum osmolality
 
 
 
 
Measure urine sodium
 
 
25 to 40 mEq/L
• Infuse Isotonic saline 1 liter over 1 hour
• Remeasure urine sodium
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Urine Osm < 100
 
 
 
 
 
 
 
 
 
 
Hight > 40 mEq/L
Hypovolemic Hyponatremia
• Renal loss
 
 
 
 
 
 
 
 
 
 
 
Yes
 
 
 
 
 
 
 
 
 
 
No
 
Urine osmolality measured After therapy initiated
 
Yes
 
 
 
Use of diuretics
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Recovery from one of the followings:
• Mild hypovolemia(Patients given isotonic fluids
Hypopituitarism
(Patients given glucocorticoids))
 
 
 
Low cortisol,
Positive ACTH stimulation

Primary adrenal insufficiency
 
 
 
Urine Na > 40 mEq/L
 
No
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Head injury/surgery
Cerebral-salt wasting
 
 
 
 
 
 
 
No
 
Yes
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Patient with rapid water consumption
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Ensure that sodium intake > 150 mEq/L over next 24 hours (infuse 1 liter of isotonic fluid over one or more hour)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Remeasure urine osmolality and sodium
 
 
 
 
 
 
 
No
 
Yes
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
High-fluid
low-protein diet including:
Beer potomania
• Tea and toast diet
 
Water intoxication:
Psychosis
• Endurance activity (Marathone)
Ecstasy use
 
 
 
 
 
Urine Na >40 or
Urine Osm > 100
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Urine Na < 40 or
Urine Osm < 100
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Hypovolemic Hyponatremia
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Check for:
• Glucocorticoid deficiency with
Cortisol level and ACTH stimulationand
Hypothyroidism with TSH
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
check morning cortisol and
ACTH stimulation test
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Yes
 
No
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Glucocorticoid deficiency
 
Elevated TSH
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
No
 
 
Yes
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
SIAD
Nephrogenic SIAD
Reset Osmostat
 
 
Severe Hypothyroidism
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Evaluate underlying etiology
 
 
 
 
 
 
 
 
 

References

  1. F. S. Apple, D. D. Koch, S. Graves & J. H. Ladenson (1982). "Relationship between the direct-potentiometric and flame-photometric measurement of sodium in the blood". Clinical chemistry. 28 (9): 1931–1935. PMID 7127808. Unknown parameter |month= ignored (help)
  2. Hussain, Iram; Ahmad, Zahid; Garg, Abhimanyu (2015). "Extreme hypercholesterolemia presenting with pseudohyponatremia - a case report and review of the literature". Journal of Clinical Lipidology. 9 (2): 260–264. doi:10.1016/j.jacl.2014.11.007. ISSN 1933-2874.
  3. Adrogué, Horacio J.; Madias, Nicolaos E. (2014). "Diagnosis and Treatment of Hyponatremia". American Journal of Kidney Diseases. 64 (5): 681–684. doi:10.1053/j.ajkd.2014.06.001. ISSN 0272-6386.
  4. Sahay, Manisha; Sahay, Rakesh (2014). "Hyponatremia: A practical approach". Indian Journal of Endocrinology and Metabolism. 18 (6): 760. doi:10.4103/2230-8210.141320. ISSN 2230-8210.
  5. E. J. Hoorn, M. L. Halperin & R. Zietse (2005). "Diagnostic approach to a patient with hyponatraemia: traditional versus physiology-based options". QJM : monthly journal of the Association of Physicians. 98 (7): 529–540. doi:10.1093/qjmed/hci081. PMID 15955797. Unknown parameter |month= ignored (help)

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