Thrombotic thrombocytopenic purpura pathophysiology: Difference between revisions

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== Pathophysiology ==
== Pathophysiology ==
* The exact pathogenesis of TTP is not completely understood.<ref name="pmid20058209">{{cite journal |vauthors=Tsai HM |title=Pathophysiology of thrombotic thrombocytopenic purpura |journal=Int. J. Hematol. |volume=91 |issue=1 |pages=1–19 |date=January 2010 |pmid=20058209 |pmc=3159000 |doi=10.1007/s12185-009-0476-1 |url=}}</ref>
* The exact [[pathogenesis]] of TTP is not completely understood.<ref name="pmid20058209">{{cite journal |vauthors=Tsai HM |title=Pathophysiology of thrombotic thrombocytopenic purpura |journal=Int. J. Hematol. |volume=91 |issue=1 |pages=1–19 |date=January 2010 |pmid=20058209 |pmc=3159000 |doi=10.1007/s12185-009-0476-1 |url=}}</ref>
* It is understood that TTP is caused by either deficiency of a plasma metalloprotease, ADAMTS13( ('''A''' '''D'''isintegrin '''A'''nd '''M'''etalloprotease with a '''T'''hrombo'''S'''pondin type 1 motif, member '''13'''). ADAMTS13 is member of human family the ADAMTS.<ref name="pmid15554875">{{cite journal |vauthors=Porter S, Clark IM, Kevorkian L, Edwards DR |title=The ADAMTS metalloproteinases |journal=Biochem. J. |volume=386 |issue=Pt 1 |pages=15–27 |date=February 2005 |pmid=15554875 |pmc=1134762 |doi=10.1042/BJ20040424 |url=}}</ref>
* It is understood that TTP is caused by either [[deficiency]] of a [[plasma]] [[Metalloproteinase|metalloprotease]], [[ADAMTS13]]( ('''A''' '''D'''isintegrin '''A'''nd [[Metalloproteinase|'''M'''etalloprotease]] with a '''T'''hrombo'''S'''pondin type 1 motif, member '''13''').
* ADAMTS13 is  a plasma reprolysin-like metalloprotease divides von Willebrand factor (VWF).<ref name="pmid23809107">{{cite journal |vauthors=Zheng XL |title=Structure-function and regulation of ADAMTS-13 protease |journal=J. Thromb. Haemost. |volume=11 Suppl 1 |issue= |pages=11–23 |date=June 2013 |pmid=23809107 |pmc=3713533 |doi=10.1111/jth.12221 |url=}}</ref>
* [[ADAMTS13]] is member of human family the ADAMTS.<ref name="pmid15554875">{{cite journal |vauthors=Porter S, Clark IM, Kevorkian L, Edwards DR |title=The ADAMTS metalloproteinases |journal=Biochem. J. |volume=386 |issue=Pt 1 |pages=15–27 |date=February 2005 |pmid=15554875 |pmc=1134762 |doi=10.1042/BJ20040424 |url=}}</ref>
* The von Willebrand factor (VWF) is produced by the endothelial cells as an ultra-high-molecular-weight multimers. Normally, VWF is sliced by a plasma metalloproteinase called ADAMTS13 into smaller multimers. When the activity or the amount of the protease is not enough, the ultra-high-molecular-weight multimers of VWF commence platelet aggregation and thrombosis in small vessels.<ref name="pmid20058209" />
* [[ADAMTS13]] is  a [[plasma]] reprolysin-like [[Metalloproteinase|metalloprotease]] divides [[Von Willebrand factor|von Willebrand factor (VWF)]].<ref name="pmid23809107">{{cite journal |vauthors=Zheng XL |title=Structure-function and regulation of ADAMTS-13 protease |journal=J. Thromb. Haemost. |volume=11 Suppl 1 |issue= |pages=11–23 |date=June 2013 |pmid=23809107 |pmc=3713533 |doi=10.1111/jth.12221 |url=}}</ref>
* Autoantibodies against the von Willebrand factor (VWF) cleaving metalloprotease ADAMTS-13. severe deficiency of plasma ADAMTS-13 activity with or without detectable inhibitory autoantibodies against ADAMTS-13 supports the diagnosis of TTP.
* The [[von Willebrand factor]] ([[Von Willebrand factor|VWF]]) is produced by the [[endothelial]] [[Cell (biology)|cells]] as an [[Ultra high molecular weight polyethylene|ultra-high-molecular-weight multimers]]. Normally, [[VWF]] is sliced by a [[plasma]] [[metalloproteinase]] called [[ADAMTS13]] into smaller multimers. When the [[Activity (chemistry)|activity]] or the [[Amount of substance|amount]] of the [[protease]] is not enough, the [[Ultra high molecular weight polyethylene|ultra-high-molecular-weight multimers]] of [[Von Willebrand factor|VWF]] commence [[platelet]] [[aggregation]] and [[Thrombosis|thrombosi]]<nowiki/>s in small [[vessels]].<ref name="pmid20058209" />
* [[Autoantibodies]] against the [[von Willebrand factor]] ([[VWF]]) cleaving [[Metalloproteinase|metalloprotease]] [[ADAMTS13|ADAMTS-13]]. Severe [[deficiency]] of [[plasma]] [[ADAMTS13|ADAMTS-13]] activity with or without detectable [[inhibitory]] [[Autoantibody|autoantibodies]] against [[ADAMTS13|ADAMTS-13]] supports the [[diagnosis]] of [[TTP]].
* [[Deficiency]] of [[ADAMTS13]] is caused by [[gene]] [[Mutation|mutations]] or [[Acquired disorder|acquired]]. [[Autoantibody|Autoantibodies]] is main to the [[pathophysiology]] of TTP. Ultra-large [[VWF]] [[Multimeric protein|multimers]] are breaking down by ADAMTS13 enzyme .
* In [[ADAMTS13]] [[deficiency]], large [[Von willebrand factor a domain containing 7|von willebrand factor]] ([[VWF]]) [[Multimeric protein|multimers]] collect leading to [[platelet]] [[aggregation]], [[hemolysis]] and microthrombi formation. [[Organ (anatomy)|Organs]] are damaged by microthrombi that  it cause [[ischemia]] is leading to damage to end [[organs]].
* The most common [[organs]] being  damaged are [[central nervous system]] ([[CNS]]) and [[Kidney|kidneys]].
* [[Thrombocytopenia]] results from [[platelet]] [[Consumption coagulopathy|consumption]] during thrombus formation.
* [[Anemia]] results from [[hemolytic]] destruction of [[red blood cells]] as they pass through small [[Blood vessel|vessels]] that are partially occluded by [[thrombi]].
==Microscopic Pathology==
==Microscopic Pathology==
On microscopic [[Histopathological|histopathologica]]<nowiki/>l analysis finding of [[Hemolytic-uremic syndrome|HUS]].
On microscopic [[Histopathological|histopathologica]]<nowiki/>l analysis finding of [[Hemolytic-uremic syndrome|TTP]].
 
 
*Granular (muddy brown) casts
*Granular (muddy brown) casts



Revision as of 19:50, 26 September 2018

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: Sogand Goudarzi, MD [2]

Overview

The exact pathogenesis of TTP is not fully understood.

It is thought that TTP is caused by deficiency of a plasma metalloprotease, ADAMTS13.

Pathophysiology

Microscopic Pathology

On microscopic histopathological analysis finding of TTP.


  • Granular (muddy brown) casts
  • Characteristic fibrin thrombi in glomerular and interstitial capillaries
  • Slough into tubular lumen
High magnification microscopy of HUS Source:By Nephron [CC BY-SA 3.0 (https://creativecommons.org/licenses/by-sa/3.0) or GFDL (http://www.gnu.org/copyleft/fdl.html)], from Wikimedia Commons

Genetics

Genes involved in the pathogenesis of TTP include:[4]

  • mutations in the ADAMTS13 gene.
  • The development of TTP is the result of inherited ADAMTS13 deficiency but mild phenotype with increased von Willebrand factor level. Upshaw–Schulman syndrome is hereditary of TTP.
  • Among some patients with severe, hereditary ADAMTS13 deficiency do not have signs or symptoms of TTP until their adulthoods .[5]

Microscopic Pathology

On microscopic histopathological analysis finding of TTP.


  • Granular (muddy brown) casts
  • Characteristic fibrin thrombi in glomerular and interstitial capillaries
  • Slough into tubular lumen
High magnification microscopy of HUS Source:By Nephron [CC BY-SA 3.0 (https://creativecommons.org/licenses/by-sa/3.0) or GFDL (http://www.gnu.org/copyleft/fdl.html)], from Wikimedia Commons

References

  1. 1.0 1.1 Tsai HM (January 2010). "Pathophysiology of thrombotic thrombocytopenic purpura". Int. J. Hematol. 91 (1): 1–19. doi:10.1007/s12185-009-0476-1. PMC 3159000. PMID 20058209.
  2. Porter S, Clark IM, Kevorkian L, Edwards DR (February 2005). "The ADAMTS metalloproteinases". Biochem. J. 386 (Pt 1): 15–27. doi:10.1042/BJ20040424. PMC 1134762. PMID 15554875.
  3. Zheng XL (June 2013). "Structure-function and regulation of ADAMTS-13 protease". J. Thromb. Haemost. 11 Suppl 1: 11–23. doi:10.1111/jth.12221. PMC 3713533. PMID 23809107.
  4. Conboy E, Partain PI, Warad D, Kluge ML, Arndt C, Chen D, Rodriguez V (January 2018). "A Severe Case of Congenital Thrombotic Thrombocytopenia Purpura Resulting From Compound Heterozygosity Involving a Novel ADAMTS13 Pathogenic Variant". J. Pediatr. Hematol. Oncol. 40 (1): 60–62. doi:10.1097/MPH.0000000000000895. PMID 28678087.
  5. Fujimura Y, Matsumoto M, Isonishi A, Yagi H, Kokame K, Soejima K, Murata M, Miyata T (July 2011). "Natural history of Upshaw-Schulman syndrome based on ADAMTS13 gene analysis in Japan". J. Thromb. Haemost. 9 Suppl 1: 283–301. doi:10.1111/j.1538-7836.2011.04341.x. PMID 21781265.

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