Syndrome of inappropriate antidiuretic hormone classification: Difference between revisions
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==Classification== | ==Classification== | ||
[[SIADH]] may be classified in to several sub-types based on the pattern of AVP secretion across a range of plasma osmolalities: | [[SIADH]] may be classified in to several sub-types based on the pattern of[[ AVP]][[ secretion]] across a range of plasma[[ osmolalities]]: | ||
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* The commonest form of [[SIADH]] responsible for a much higher proportion of SIADH, at around 60–70%. | * The commonest form of [[SIADH]] responsible for a much higher proportion of SIADH, at around 60–70%. | ||
* Exhibit excessive, random secretion of AVP, with loss of the close linear relationship between plasma osmolality and plasma[[ AVP]]. | * Exhibit excessive, random secretion of AVP, with loss of the close linear relationship between plasma[[ osmolality]] and plasma[[ AVP]]. | ||
*Common in [[lung cancer]] | *Common in [[lung cancer]] | ||
* In[[ vitro studie]]s have demonstrated that some lung tumours synthesize AVP, and that tumour tissue stains positive for AVP[[ mRNA]] | * In[[ vitro studie]]s have demonstrated that some lung tumours synthesize AVP, and that [[tumour]] tissue stains positive for AVP[[ mRNA]] | ||
*Plasma AVP concentrations in type A SIADH are not suppressed [[physiologically]] by drinking , which makes patients vulnerable to the development of severe [[hyponatremia]]. | *Plasma [[AVP]] concentrations in type A SIADH are not suppressed [[physiologically]] by drinking , which makes patients vulnerable to the development of severe [[hyponatremia]]. | ||
* Studies have also demonstrated a lower[[ osmotic]] threshold for [[thirst]] appreciation in this type of SIADH. | * Studies have also demonstrated a lower[[ osmotic]] threshold for [[thirst]] appreciation in this type of [[SIADH]]. | ||
* This type of SIADH is also characteristic of [[nasopharyngeal tumours]], which also stain positive for AVP mRNA | * This type of SIADH is also characteristic of [[nasopharyngeal tumours]], which also stain positive for AVP[[ mRNA]] | ||
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| style="padding: 5px 5px; background: #DCDCDC; font-weight: bold; text-align:center;" |Type B | | style="padding: 5px 5px; background: #DCDCDC; font-weight: bold; text-align:center;" |Type B | ||
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| style="padding: 5px 5px; background: #DCDCDC; font-weight: bold; text-align:center;" |[[TypeC]] | | style="padding: 5px 5px; background: #DCDCDC; font-weight: bold; text-align:center;" |[[TypeC]] | ||
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* A rare condition characterized by failure to suppress AVP secretion at plasma osmolalities below the osmotic threshold. | * A rare condition characterized by failure to suppress AVP secretion at plasma osmolalities below the [[osmotic]] threshold. | ||
* Plasma AVP concentrations are thus inappropriately high at low plasma osmolalities, but there is a normal relationship between plasma osmolality and plasma AVP at physiological plasma osmolalities. | * Plasma [[AVP]] concentrations are thus inappropriately high at low plasma osmolalities, but there is a normal relationship between plasma osmolality and plasma AVP at physiological plasma osmolalities. | ||
*This variant may be due to dysfunction of inhibitory neurons in the hypothalamus, leading to persistent low-grade basal AVP secretion. | *This variant may be due to dysfunction of inhibitory neurons in the[[ hypothalamus]], leading to persistent low-grade basal AVP secretion. | ||
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*Is a rare clinical picture of [[SIADH]] with low or undetectable[[ AVP]]evels and no detectable abnormality in circulating AVP response . | *Is a rare clinical picture of [[SIADH]] with low or undetectable[[ AVP]]evels and no detectable abnormality in circulating AVP response . | ||
*It is thought that a nephrogenic SIADH (NSIAD) may be responsible for this picture . | *It is thought that a nephrogenic SIADH (NSIAD) may be responsible for this picture . | ||
*Gain-of-function mutations in the V2 receptor leading to a clinical picture of SIADH, with undetectable AVP levels, have been described. | *Gain-of-function[[ mutations]] in the V2 receptor leading to a clinical picture of SIADH, with undetectable AVP levels, have been described. | ||
*The identified mutations had different nucleotide substitutions causing different levels of V2 receptor activation. | *The identified mutations had different [[nucleotide]] substitutions causing different levels of V2 receptor activation. | ||
*This syndrome appears to be inherited in an X-linked manner,although heterozygous females may have varying degrees of inappropriate antidiuresis. Owing to variable expressivity of the gene involved, NSIAD may be clinically undetectable for years, until other contributing factors in later life lead to clinically significant hyponatraemia . <ref name="pmid20164214">{{cite journal |vauthors=Hannon MJ, Thompson CJ |title=The syndrome of inappropriate antidiuretic hormone: prevalence, causes and consequences |journal=Eur. J. Endocrinol. |volume=162 Suppl 1 |issue= |pages=S5–12 |year=2010 |pmid=20164214 |doi=10.1530/EJE-09-1063 |url=}}</ref> | *This syndrome appears to be inherited in an X-linked manner,although heterozygous females may have varying degrees of inappropriate antidiuresis. Owing to variable expressivity of the [[gene]] involved,[[ NSIAD]] may be clinically undetectable for years, until other contributing factors in later life lead to clinically significant hyponatraemia . <ref name="pmid20164214">{{cite journal |vauthors=Hannon MJ, Thompson CJ |title=The syndrome of inappropriate antidiuretic hormone: prevalence, causes and consequences |journal=Eur. J. Endocrinol. |volume=162 Suppl 1 |issue= |pages=S5–12 |year=2010 |pmid=20164214 |doi=10.1530/EJE-09-1063 |url=}}</ref> | ||
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Revision as of 16:39, 14 August 2017
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Vindhya BellamKonda, M.B.B.S [2]
Overview
SIADH may be classified into several sub-types based on the pattern of AVP( arginine vasopressin) secretions across a range of plasma osmolalities: Type A, type B, type C, type D.
Classification
SIADH may be classified in to several sub-types based on the pattern ofAVPsecretion across a range of plasmaosmolalities:
| Classification | Features |
|---|---|
| TypeA |
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| Type B |
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| TypeC |
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| Type D |
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References
- ↑ Hannon MJ, Thompson CJ (2010). "The syndrome of inappropriate antidiuretic hormone: prevalence, causes and consequences". Eur. J. Endocrinol. 162 Suppl 1: S5–12. doi:10.1530/EJE-09-1063. PMID 20164214.