Hyponatremia diagnostic study of choice

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Diagnostic Study of Choice
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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

• 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:
  • 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 {{CMG}}, your name template, and the microchapter navigation template you created at the beginning.
• Remember to create links within WikiDoc by placing [[square brackets]] 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.

Gold standard/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]

	Sensitivity	Specificity
Test 1	✔	...%
Test 2	...%	✔

✔= The best test based on the feature

Diagnostic results

The following result of [investigation name] is confirmatory of [disease name]:

• Result 1
• Result 2

Sequence of Diagnostic Studies

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

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

Hypotonic Hyponatremia

Isoosmolar or Hyperosmolar hyponatremia

• Low GFR • History of Thiazide use

Yes

• Post TURP or hysteroscopy (Glycine, Sorbitol) • Direct sodium by direct potentiometry if normal measure total protein and lipid

No

• Renal failure • Thiazide induce hyponatremia

Patients with edema (pulmonary, peripheral), ascites

Signs and Symptoms of hypovolemia (↓ BP, Orthostatic hypotension)

Heart failure Cirrhosis

Low 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 osmolality<100

Yes

Hight > 40 mEq/L Hypovolemic Hyponatremia Renal loss

No

Urine osmolality measured After therapy initiated

Yes

Use of diuretics

Urine sodium> 40 mEq/L

No

Recovery from one of the followings: • Mild hypovolemia(Patients given isotonic fluids • Hypopituitarism(Patients given glucocorticoids))

Low cortisol, Positive ACTH stimulation Primary adrenal insufficiency

No

Yes

Head injury/surgery Cerebral-salt wasting

Patient with rapid water consumption

Yes

Water intoxication: • Psychosis • Endurance activity(Marathone) • Ecstasy use

Ensure that sodium intake > 150 mEq/L over next 24 hours (infuse 1 liter of isotonic fluid over one or more hour)

No

Remeasure urine osmolality and sodium

High-fluid, low-protein diet including: • Beer potomania • Tea and toast diet

Urine Na >40 or Urine osm > 100

Urine Na < 40 or Urine osmo< 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

SIADH Nephrogenic SIADH Reset Osmostat

Severe Hypothyroidism

Evaluate underlying etiology

• 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 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].