Hyponatremia diagnostic study of choice: Difference between revisions

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Revision as of 13:55, 4 June 2018

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 flase 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 its 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 :

2

For differential diagnosis click here.

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

{{familytree | | | | | N01 | | | N02 | | | | | |N01=SIAD
Nephrogenic [[SIADH|SIAD
Reset Osmostat|N02=Severe Hypothyroidism}}

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

Evaluate underlying etiology

References

↑ F. S. Apple, D. D. Koch, S. Graves & J. H. Ladenson (1982). "Relationship between direct-potentiometric and flame-photometric measurement of sodium in blood". Clinical chemistry. 28 (9): 1931–1935. PMID 7127808. Unknown parameter |month= ignored (help)
↑ 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.
↑ 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.
↑ 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.
↑ 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)

Template:WH Template:WS

[1] F. S. Apple, D. D. Koch, S. Graves & J. H. Ladenson (1982). "Relationship between direct-potentiometric and flame-photometric measurement of sodium in blood". Clinical chemistry. 28 (9): 1931–1935. PMID 7127808. Unknown parameter |month= ignored (help)

[HussainAhmad20152-2] 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.

[AdroguéMadias2014-3] 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.

[SahaySahay2014-4] 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)

[1]

[2]

[3]

[4]

[5]

@@ Line 102: / Line 102: @@
 {{familytree | | | | | | | | A01 |A01=Serum sodium < 135 mEq/L}}
 {{familytree | | | | | | | | |!| | | | | | | }}
-{{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 | | | | | | | | 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 | | | | | | | | B01 | | | | | |B01=Measure '''serum Osmolality'''}}
+{{familytree | | | | | | | | B01 | | | | | |B01=Measure '''[[serum Osmolality]]'''}}
 {{familytree | | | |,|-|-|-|-|^|-|-|-|-|.| | | }}
 {{familytree | | | B01 | | | | | | | | B02 | | |B01='''Low < 280 momol/kg''' |B02='''Normal or High<br>> 280 momol/kg'''}}
@@ Line 110: / Line 110: @@
 {{familytree | | | C01 | | | | | | | | C02 |C01='''Hypotonic Hyponatremia'''|C02='''Isoosmolar or Hyperosmolar hyponatremia'''}}
 {{familytree | | | |!| | | | | | | | | |!| }}
-{{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>• Direct sodium by direct potentiometry if normal measure total protein and lipid|boxstyle D01=text-align: left; | }}
+{{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 | | | E01 | | | D02 |-| E02 |E01=No||D02=Yes|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 | 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 | G01 | | | | |!| | | | | | | | |G01=Heart failure<br> Cirrhosis|}}
+{{familytree | G01 | | | | |!| | | | | | | | |G01=[[Heart failure]]<br> [[Cirrhosis]]|}}
-{{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 space losses</td></tr></table>}}
+{{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 | | | J01 | | | | | J02 |!| | | |J01=No|J02=Yes}}
 {{familytree | | | |!| | | | | | |!| |!| | | |}}
-{{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 | | | 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 | | | 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 | | | |!| | | I02 | | | | | |!| |I02=Yes|}}
-{{familytree | | | G01 | | G02 |-| G03 | |)| G04 |G01=No|G02='''Urine osmolality''' measured '''After therapy initiated'''|G03=Yes|G04=Use of diuretics}}
+{{familytree | | | G01 | | G02 |-| G03 | |)| G04 |G01=No|G02='''[[Urine osmolality]]''' measured '''After therapy initiated'''|G03=Yes|G04=Use of diuretics}}
 {{familytree | | | |!| | | |!| | | |!| | |!| |}}
-{{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 | | | |!| | | |!| | | 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]]}}
 {{Family tree| | | L01 | | L02 | | | | | |!| | | |L01='''Urine <sub>Na</sub> > 40 mEq/L'''|L02=No}}
-{{familytree | |,|-|^|-|.| |!| | | | | | |`| P03 |P03='''Head injury/surgery'''<br>Cerebral-salt wasting}}
+{{familytree | |,|-|^|-|.| |!| | | | | | |`| P03 |P03='''Head injury/surgery'''<br>[[Cerebral-salt wasting]]}}
 {{familytree | P01 | | P02 |!| | | | | | | | | | |P01=No|P02=Yes}}
 {{familytree | |!| | | |!| |!| | | | | | | | | | }}
@@ Line 136: / Line 136: @@
 {{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 | |!| | | |!| | | 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 | | | |`| 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 | | | | | X01 | | | | | | | | | | |X01= check '''morning [[cortisol]]''' and<br>'''ACTH stimulation test'''}}
 {{familytree | | | |,|-|^|-|.| | | | | | | |}}
 {{familytree | | | C01 | | C02 | | | | | | | |C01=Yes|C02=No}}
@@ Line 151: / Line 151: @@
 {{familytree | | | | | B01 | | | B02 | | | | | |B01=No|B02=Yes}}
 {{familytree | | | | | |!| | | | |!| | | | | | |}}
-{{familytree | | | | | N01 | | | N02 | | | | | |N01=SIAD<br>Nephrogenic SIAD<br>Reset Osmostat|N02=Severe Hypothyroidism}}
+{{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]]}}