{"id":26,"date":"2020-05-26T22:30:00","date_gmt":"2020-05-26T22:30:00","guid":{"rendered":"https:\/\/avo6.com\/index.php\/2020\/05\/26\/la-coagulation-physiologie-et-exploration-biologique\/"},"modified":"2022-09-28T20:38:42","modified_gmt":"2022-09-28T20:38:42","slug":"la-coagulation-physiologie-et-exploration-biologique","status":"publish","type":"post","link":"https:\/\/avo6.com\/?p=26","title":{"rendered":"LA COAGULATION : PHYSIOLOGIE ET EXPLORATION BIOLOGIQUE"},"content":{"rendered":"
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GENERALITES<\/span><\/span><\/span><\/b><\/div>\n
Il s\u2019agit du processus de coagulation du plasma sanguin aboutissant \u00e0 la transformation du \ufb01brinog\u00e8ne plasmatique circulant soluble en \ufb01brine insoluble enserrant le clou plaquettaire par le biais d\u2019une s\u00e9rie de r\u00e9actions enzymatiques dont le contr\u00f4le continu permet une restriction locale sans diffusion \u00e0 distance de la zone l\u00e9sionnelle.<\/span><\/div>\n
Le processus central de la coagulation est la g\u00e9n\u00e9ration de la mol\u00e9cule de thrombine, enzyme cl\u00e9 de la coagulation, permettant la transformation du \ufb01brinog\u00e8ne en \ufb01brine et assurant la r\u00e9troactivation et l\u2019ampli\ufb01cation des diff\u00e9rentes \u00e9tapes tant de la coagulation que de l\u2019h\u00e9mostase primaire.<\/span><\/div>\n

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LES PARTICIPANTS<\/span><\/span><\/b><\/div>\n
1.\u00a0\u00a0\u00a0\u00a0\u00a0<\/span><\/span><\/span><\/b><\/span>El\u00e9ments cellulaires\u00a0:<\/span><\/span><\/b>
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\u00a7\u00a0\u00a0<\/span><\/span><\/span>Les cellules endoth\u00e9liales et les monocytes<\/span><\/div>\n
\u00a7\u00a0\u00a0<\/span><\/span><\/span>Les plaquettes activ\u00e9es<\/span><\/div>\n
\u00a7\u00a0\u00a0<\/span><\/span><\/span>Les monocytes<\/span><\/div>\n
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2.\u00a0\u00a0\u00a0\u00a0\u00a0<\/span><\/span><\/span><\/b><\/span>Facteurs\u00a0\u00a0<\/span>de coagulation\u00a0:<\/span><\/span><\/b><\/div>\n
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\u00a7\u00a0\u00a0<\/span><\/span><\/span>Ce sont des prot\u00e9ines plasmatiques reparties en deux\u00a0 groupes principaux\u00a0:\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/span><\/span><\/div>\n
\u00fc\u00a0\u00a0<\/span><\/span><\/span>Les prot\u00e9ines \u00e0 activit\u00e9 enzymatique.<\/span><\/div>\n
\u00fc\u00a0\u00a0<\/span><\/span><\/span>Les prot\u00e9ines d\u00e9nu\u00e9es d\u2019activit\u00e9 enzymatique mais servant de cofacteurs<\/span><\/div>\n
\u00a7\u00a0\u00a0<\/span><\/span><\/span>Elles sont au nombre de 12 et bien qu\u2019elles\u00a0\u00a0<\/span>aient chacune un nom usuel, un num\u00e9ro en chiffre romain leur a \u00e9t\u00e9 attribu\u00e9 selon la nomenclature internationale.<\/span><\/div>\n
\u00a7\u00a0\u00a0<\/span><\/span><\/span>Les facteurs de la coagulation sont synth\u00e9tis\u00e9s au niveau du foie par l\u2019h\u00e9patocyte, et toute insuffisance h\u00e9patocellulaire s\u00e9v\u00e8re entra\u00eene une diminution globale des facteurs de la coagulation par d\u00e9faut de production.<\/span><\/div>\n
a.\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/span><\/span><\/span><\/i><\/span>Pr\u00e9curseurs enzymatiques<\/span><\/span><\/u><\/i><\/b>
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\u00a7\u00a0\u00a0<\/span><\/span><\/span>Les facteurs vitamine K-d\u00e9pendants II, VII, IX, X d\u2019une part, et les facteurs contacts XI, XII, pr\u00e9kallicr\u00e9ine d\u2019autre part, circulent dans le plasma sous la forme d\u2019un pr\u00e9curseur enzymatique inactif. Ils poss\u00e8dent un site <\/ins>actif prot\u00e9olytique au niveau de la r\u00e9gion C terminale, qui est masqu\u00e9 tant que la mol\u00e9cule n\u2019est pas activ\u00e9e.<\/span><\/div>\n
\u00a7\u00a0\u00a0<\/span><\/span><\/span>\u00a0<\/span>L\u2019activation consiste en une hydrolyse partielle de la mol\u00e9cule d\u00e9masquant le site s\u00e9rine-prot\u00e9ase. Le facteur activ\u00e9 a ainsi la capacit\u00e9 d\u2019activer par hydrolyse un autre facteur dans une v\u00e9ritable cascade enzymatique.<\/span><\/div>\n
\u00a7\u00a0\u00a0<\/span><\/span><\/span>La vitamine K est n\u00e9cessaire \u00e0 l\u2019acquisition des propri\u00e9t\u00e9s\u00a0\u00a0\u00a0<\/span>fonctionnelles des facteurs II, VII, IX et X.<\/span><\/div>\n
\u00a7\u00a0\u00a0<\/span><\/span><\/span>\u00a0<\/span>Les facteurs contacts (facteurs XI, XII, pr\u00e9kallicr\u00e9ine), dont la synth\u00e8se ne d\u00e9pend pas de la vitamine K, sont activ\u00e9s\u00a0\u00a0<\/span>par le contact avec une surface non mouillable (verre du tube par exemple), ou charg\u00e9e n\u00e9gativement (sous-endoth\u00e9lium). \u00a0<\/span><\/div>\n
b.\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/span><\/span><\/span><\/i><\/b><\/span>Le \ufb01brinog\u00e8ne<\/span><\/u><\/i>\u00a0\u00a0<\/span><\/span><\/u><\/span>\u00a0<\/span>\u00a0\u00a0\u00a0<\/span><\/u><\/span><\/b>
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\u00a7\u00a0\u00a0<\/span><\/span><\/span>Est un polypeptide synth\u00e9tis\u00e9 par l\u2019h\u00e9patocyte et son taux plasmatique est de l\u2019ordre de 2 \u00e0 4 g\/l, taux accru lors des \u00e9tats infectieux ou in\ufb02ammatoires ou bien diminu\u00e9 par consommation excessive dans certains \u00e9tats pathologiques [CIVD].<\/span><\/div>\n
\u00a7\u00a0\u00a0<\/span><\/span><\/span>L\u2019effet hydrolytique de la thrombine permet la polym\u00e9risation des cha\u00eenes de \ufb01brinog\u00e8ne en gel de \ufb01brine.<\/span><\/div>\n
\u00a7\u00a0\u00a0<\/span><\/span><\/span>Le facteur XIII, ou facteur de stabilisation de la \ufb01brine, renforce la coh\u00e9sion des mol\u00e9cules de \ufb01brine par la cr\u00e9ation de liaisons covalentes intermol\u00e9culaires, rendant le r\u00e9seau de \ufb01brine plus stable et plus solide.<\/span><\/div>\n
c.\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/span><\/span><\/span><\/i><\/b><\/span>\u00a0<\/span>Les Cofacteurs : facteurs V et VIII<\/span><\/span><\/u><\/i><\/b>
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\u00a7\u00a0\u00a0<\/span><\/span><\/span>Les facteurs V et VIII sont d\u00e9pourvus d\u2019activit\u00e9 enzymatique mais acc\u00e9l\u00e8rent les r\u00e9actions entre une enzyme et son substrat, d\u2019o\u00f9 leur nom de cofacteurs.<\/span><\/div>\n
\u00a7\u00a0\u00a0<\/span><\/span><\/span>Ils sont activ\u00e9s par la thrombine (Va et VIIIa) qui r\u00e9alise une hydrolyse partielle des mol\u00e9cules.<\/span><\/div>\n
\u00a7\u00a0\u00a0<\/span><\/span><\/span>\u00a0<\/span>Les facteurs Va et VIIIa ont donc un r\u00f4le de potentialisateur des interactions enzymatiques et interviennent respectivement au sein de deux complexes enzymatiques de la cascade de la coagulation, le complexe tenase (VIIIa) et le complexe prothrombinase (Va).<\/span><\/div>\n
\u00a7\u00a0\u00a0<\/span><\/span><\/span>Ces facteurs ne sont pas vitamine-K d\u00e9pendants et sont synth\u00e9tis\u00e9s dans l\u2019h\u00e9patocyte.<\/span><\/div>\n
\u00a7\u00a0\u00a0<\/span><\/span><\/span>\u00a0<\/span>Le facteur VIII, ou facteur antih\u00e9mophilique A, circule dans le plasma associ\u00e9 au VWF qui joue ainsi le r\u00f4le de prot\u00e9ine transporteuse.<\/span><\/div>\n
3.\u00a0\u00a0\u00a0\u00a0\u00a0<\/span><\/span><\/span><\/b><\/span>Phospholipides activateurs de la coagulation<\/span><\/b>
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\u00a7\u00a0\u00a0<\/span><\/span><\/span>Ils constituent une surface mol\u00e9culaire catalytique permettant le d\u00e9clenchement de la coagulation et\u00a0\u00a0<\/span>sont expos\u00e9s lors de conditions pathologiques ou r\u00e9actionnelles.<\/span><\/div>\n
\u00a7\u00a0\u00a0<\/span><\/span><\/span>La \ufb01xation aux phospholipides membranaires de l\u2019enzyme prot\u00e9olytique, de son substrat et du cofacteur catalytique acc\u00e9l\u00e8re grandement leurs interactions.<\/span><\/div>\n
\u00a7\u00a0\u00a0<\/span><\/span><\/span>Les phospholipides impliqu\u00e9s dans le d\u00e9clenchement\u00a0\u00a0<\/span>de la coagulation comprennent:<\/span><\/div>\n
\u00fc\u00a0\u00a0<\/span><\/span><\/span>La phosphatidyls\u00e9rine plaquettaire(F3P) : exprim\u00e9e \u00e0 la surface de la membrane plaquettaire lors de son activation<\/span><\/div>\n
\u00fc\u00a0\u00a0<\/span><\/span><\/span>Le facteur tissulaire, prot\u00e9ine transmembranaire, est exprim\u00e9\u00a0\u00a0<\/span>par les cellules sous-endoth\u00e9liales, \ufb01broblastes et cellules musculaires lisses, il est expos\u00e9 aux prot\u00e9ines procoagulantes lors d\u2019une br\u00e8che vasculaire, avec mise \u00e0 nu des structures sous-endoth\u00e9liales.<\/span><\/div>\n
\u00a7\u00a0\u00a0<\/span><\/span><\/span>Le facteur tissulaire est le r\u00e9cepteur du facteur VII activ\u00e9 et leur liaison d\u00e9clenche le processus de cascade enzymatique de la coagulation.<\/span><\/div>\n
4.\u00a0\u00a0\u00a0\u00a0\u00a0<\/span><\/span><\/span><\/b><\/span>Inhibiteurs de la coagulation<\/span><\/span><\/b>
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\u00a7\u00a0\u00a0<\/span><\/span><\/span>Trois groupes d\u2019inhibiteurs selon leur structure et fonction :<\/span><\/div>\n
\u00fc\u00a0\u00a0<\/span><\/span><\/span>Syst\u00e8me de la prot\u00e9ine C activ\u00e9e r\u00e9gule la coagulation par prot\u00e9olyse et fait intervenir :<\/span><\/div>\n
\u00d8\u00a0\u00a0<\/span><\/span><\/span>Deux prot\u00e9ines plasmatiques vit K d\u00e9pendantes, la prot\u00e9ine C (zymog\u00e8ne d’une serine prot\u00e9ase) et son cofacteur, la prot\u00e9ine S.<\/span><\/div>\n
\u00d8\u00a0\u00a0<\/span><\/span><\/span>Un r\u00e9cepteur membranaire : thrombomoduline<\/span><\/div>\n
\u00fc\u00a0\u00a0<\/span><\/span><\/span>Inhibiteurs de serine prot\u00e9ases ou serpines : Antithrombine+++ (AT), Cofacteur II de l’h\u00e9parine (HCII), \u03b11-antitrypsine et C1-inhibiteur.<\/span><\/div>\n
\u00fc\u00a0\u00a0<\/span><\/span><\/span>TFPI (Tissue Factor Pathway Inhibitor) appartient aux inhibiteurs type Kunitz.<\/span>
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LES ETAPES DE LA COAGULATION<\/span><\/span><\/span><\/b>
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1.\u00a0\u00a0\u00a0\u00a0\u00a0<\/span><\/span><\/span><\/b><\/span>Initiation de la coagulation\u00a0:<\/span><\/span><\/b>
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a.\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/span><\/span><\/span><\/i><\/b><\/span>Par le facteur tissulaire\u00a0:<\/span><\/span><\/u><\/i><\/b>
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\u00a7\u00a0\u00a0<\/span><\/span><\/span>Lors d’une l\u00e9sion vasculaire, le FT pr\u00e9sent dans l’adventice fixe \u00e0 la fois le F. VII et les traces de F. Vlla du sang circulant, avec autoactivation imm\u00e9diate du F. VIl . Le complexe binaire FT\/Vlla active ensuite simultan\u00e9ment les F. IX et X fix\u00e9s sur les surfaces membranaires, initiant ainsi la voie exog\u00e8ne de la coagulation<\/span><\/div>\n
b.\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/span><\/span><\/span><\/i><\/b><\/span>Par le syst\u00e8me contact\u00a0:<\/span><\/span><\/u><\/i><\/b>
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\u00a7\u00a0\u00a0<\/span><\/span><\/span>Exposition du collag\u00e8ne sous endoth\u00e9lial capable d\u2019activer le syst\u00e8me contact (pr\u00e9kallicr\u00e9ine, FXII, KHPM et FXI) aboutissant \u00e0 l\u2019activation du FXI.<\/span><\/div>\n
\u00a7\u00a0\u00a0<\/span><\/span><\/span>FXIa active le FIX en pr\u00e9sence des PLP initiant la\u00a0\u00a0<\/span>voie intrins\u00e8que de la coagulation.<\/span>
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2.\u00a0\u00a0\u00a0\u00a0\u00a0<\/span><\/span><\/span><\/b><\/span>La formation de thrombine<\/span><\/span><\/b>
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a.\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/span><\/span><\/span><\/i><\/b><\/span>Voie tissulaire :<\/span><\/span><\/u><\/i><\/b>
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\u00a7\u00a0\u00a0<\/span><\/span><\/span>Complexe FVIIa\/FT\/PLP\/Ca\u00b2+ active par prot\u00e9olyse FIX en FIXa ou FX en FXa:<\/span><\/div>\n
\u00fc\u00a0\u00a0<\/span><\/span><\/span>FIXa forme le complexe tenase avec FVIIIa (cofacteur) en pr\u00e9sence de PLP et Ca\u00b2+. Ce complexe active le FX en FXa.<\/span><\/div>\n
\u00fc\u00a0\u00a0<\/span><\/span><\/span>FXa forme le complexe prothrombinase avec le FVa (cofacteur) en pr\u00e9sence de Ca\u00b2+ et PLP. Ce complexe active le FII en thrombine.<\/span><\/div>\n
b.\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/span><\/span><\/span><\/i><\/b><\/span>Voie endog\u00e8ne\u00a0:<\/span><\/span><\/u><\/i><\/b>
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\u00a7\u00a0\u00a0<\/span><\/span><\/span>Pr\u00e9kallicr\u00e9ine est transform\u00e9e en kallicr\u00e9ine par une prot\u00e9ase de la paroi vasculaire. La kallicr\u00e9ine active le FXII qui active le FXI.<\/span><\/div>\n
\u00a7\u00a0\u00a0<\/span><\/span><\/span>FXIa active par prot\u00e9olyse le FIX avec formation du FIXa qui forme le complexe tenase et etc\u2026<\/span><\/div>\n
\u00a7\u00a0\u00a0<\/span><\/span><\/span>La thrombine form\u00e9e amplifie sa propre formation par recrutement de nouvelles plaquettes, activation des cofacteurs VIII et V et activation du FXI.<\/span><\/div>\n
3.\u00a0\u00a0\u00a0\u00a0\u00a0<\/span><\/span><\/span><\/b><\/span>La fibrinoformation<\/span><\/span><\/b>
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\u00a7\u00a0\u00a0<\/span><\/span><\/span>Au seuil critique, la thrombine convertit le fibrinog\u00e8ne en fibrine qui forme un r\u00e9seau autour de l\u2019agr\u00e9gat de plaquettes. Le caillot est stabilis\u00e9 par FXIIIa.<\/span><\/div>\n
\u00a7\u00a0\u00a0<\/span><\/span><\/span>L\u2019activation du FXIII est r\u00e9alis\u00e9e par la thrombine.<\/span><\/div>\n
\u00a7\u00a0\u00a0<\/span><\/span><\/span>FXIIIa est une transglutaminase qui stabilise le caillot en cr\u00e9ant des liaisons covalentes entre les polym\u00e8res de fibrine.<\/span><\/div>\n
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p\u00a0<\/span><\/span><\/span>Concept actuel de la coagulation\u00a0:<\/span><\/u><\/b><\/div>\n
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Etapes de la coagulation\u00a0:<\/span><\/span><\/u><\/b><\/div>\n
\u00fc\u00a0\u00a0<\/span><\/span><\/span>Initiation de la coagulation<\/span><\/i><\/b><\/span><\/div>\n
\u00a7\u00a0\u00a0<\/span><\/span><\/span>La coagulation est initi\u00e9e par le complexe FTFVIIa.<\/span><\/div>\n
\u00a7\u00a0\u00a0<\/span><\/span><\/span>FVIIa est le seul facteur existant \u00e0 l\u2019\u00e9tat de traces dans le plasma.<\/span><\/div>\n
\u00a7\u00a0\u00a0<\/span><\/span><\/span>La liaison du FVIIa au FT entra\u00eene une modification conformationnelle du FVII, g\u00e9n\u00e9rant encore du facteur VII activ\u00e9.<\/span><\/div>\n
\u00a7\u00a0\u00a0<\/span><\/span><\/span>Le complexe [FT-FVIIa] peut activer le FIX et le FX.<\/span><\/div>\n
\u00a7\u00a0\u00a0<\/span><\/span><\/span>L\u2019activation directe du FX est faible car elle est limit\u00e9e par un inhibiteur appel\u00e9 tissue factor pathway inhibitor (TFPI).<\/span><\/div>\n
\u00a7\u00a0\u00a0<\/span><\/span><\/span>L\u2019activation du FX par le FIXa est faible aussi car elle n\u00e9cessite la pr\u00e9sence d\u2019un cofacteur non pr\u00e9sent \u00e0 cette phase : le FVIIIa.<\/span><\/div>\n
\u00a7\u00a0\u00a0<\/span><\/span><\/span>Cette phase d\u2019initiation ne g\u00e9n\u00e8re donc que des traces de thrombine.<\/span><\/div>\n
\u00a7\u00a0\u00a0<\/span><\/span><\/span>La quantit\u00e9 de thrombine g\u00e9n\u00e9r\u00e9e ne suffit pas pour produire la fibrine n\u00e9cessaire \u00e0 la constitution du caillot, mais permet le d\u00e9clenchement de la phase de propagation de la coagulation.<\/span><\/div>\n
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\u00fc\u00a0\u00a0<\/span><\/span><\/span><\/span>Amplification de la coagulation<\/span><\/span><\/i><\/b>
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\u00a7\u00a0\u00a0<\/span><\/span><\/span>La thrombine g\u00e9n\u00e9r\u00e9e clive le FVIII et forme l\u2019h\u00e9t\u00e9rotrim\u00e8re FVIIIa.<\/span><\/div>\n
\u00a7\u00a0\u00a0<\/span><\/span><\/span>Apr\u00e8s que la thrombine, et \u00e0 un moindre degr\u00e9 le FXa, ont activ\u00e9 le FVIII, celui-ci se s\u00e9pare du vWF pour se lier aux phospholipides plaquettaires sur lesquels il est concentr\u00e9.<\/span><\/div>\n
\u00a7\u00a0\u00a0<\/span><\/span><\/span>C\u2019est donc \u00e0 la surface des plaquettes que se produit la phase d\u2019amplification : le FIXa g\u00e9n\u00e9r\u00e9 pendant la phase d\u2019initiation est fix\u00e9 de fa\u00e7on diffuse sur les plaquettes, o\u00f9 il se lie au FVIIIa en pr\u00e9sence de calcium.<\/span><\/div>\n
\u00a7\u00a0\u00a0<\/span><\/span><\/span>Le complexe ainsi cr\u00e9\u00e9 [IXa-VIIIa] s\u2019appelle aussi tenase ou tenase intrins\u00e8que.<\/span><\/div>\n
\u00a7\u00a0\u00a0<\/span><\/span><\/span>Dans ce complexe, le FVIIIa augmente la catalyse du FX par le FIXa d\u2019un facteur sup\u00e9rieur \u00e0 105, induisant la pr\u00e9sence de FXa en forte concentration.<\/span><\/div>\n
\u00a7\u00a0\u00a0<\/span><\/span><\/span>De plus, la thrombine active le FV en FVa qui se fixe lui aussi \u00e0 la surface des plaquettes.<\/span><\/div>\n
\u00a7\u00a0\u00a0<\/span><\/span><\/span>Le complexe [FXa-FVa] s\u2019appelle aussi complexe prothrombinase.<\/span><\/div>\n
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\u00c0 la fin de la phase d\u2019amplification se trouvent donc \u00e0 la surface des plaquettes activ\u00e9es des facteurs de coagulation activ\u00e9s en concentration importante.<\/u><\/span><\/b><\/div>\n<\/div>\n
\u00fc\u00a0\u00a0<\/span><\/span><\/span><\/span>Propagation de la coagulation\u00a0:<\/span><\/span><\/i><\/b><\/div>\n
\u00a7\u00a0\u00a0<\/span><\/span><\/span>\u00c0 la surface des plaquettes, le complexe tenase g\u00e9n\u00e8re des quantit\u00e9s importantes de FXa.<\/span><\/div>\n
\u00a7\u00a0\u00a0<\/span><\/span><\/span>L\u2019activation du FX en FXa par le complexe tenase est 50 fois sup\u00e9rieure \u00e0 celle du FX par le complexe [FT-FVIIa].<\/span><\/div>\n
\u00a7\u00a0\u00a0<\/span><\/span><\/span>Le complexe prothrombinase clive la prothrombine en thrombine, mais apr\u00e8s la phase d\u2019amplification, la pr\u00e9sence \u00e0 la surface des plaquettes de concentrations \u00e9lev\u00e9es de facteurs activ\u00e9s permet la g\u00e9n\u00e9ration explosive de quantit\u00e9s importantes de thrombine (thrombin burst).<\/span><\/div>\n
\u00a7\u00a0\u00a0<\/span><\/span><\/span>La thrombine g\u00e9n\u00e9r\u00e9e aura de multiples effets :<\/span><\/div>\n
\u00a7\u00a0\u00a0<\/span><\/span><\/span>Activation en boucle du facteur XI (FXI), du FVIII et du FV,<\/span><\/div>\n
\u00a7\u00a0\u00a0<\/span><\/span><\/span>Activation des plaquettes et surtout prot\u00e9olyse du fibrinog\u00e8ne en monom\u00e8res de fibrine. La polym\u00e9risation spontan\u00e9e de ces monom\u00e8res cr\u00e9e la trame du r\u00e9seau de fibrine qui structure le caillot.<\/span><\/div>\n
\u00a7\u00a0\u00a0<\/span><\/span><\/span>Ce caillot est consolid\u00e9 par l\u2019action du FXIII, lui-m\u00eame activ\u00e9 par la thrombine<\/span><\/div>\n
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En r\u00e9sum\u00e9 :<\/span><\/span><\/u><\/b><\/div>\n
\u00fc\u00a0\u00a0<\/span><\/span><\/span>La phase d\u2019initiation, conduit \u00e0 la g\u00e9n\u00e9ration de faibles traces de thrombine \u00e0 la surface de cellules exprimant du facteur tissulaire (FT).<\/span><\/div>\n
\u00fc\u00a0\u00a0<\/span><\/span><\/span>La phase d\u2019amplification, aboutit \u00e0 l\u2019accumulation de facteurs activ\u00e9s \u00e0 la surface des plaquettes.<\/span><\/div>\n
\u00fc\u00a0\u00a0<\/span><\/span><\/span>La phase de propagation comporte l\u2019assemblage de larges complexes enzymatiques \u00e0 la surface des plaquettes, la g\u00e9n\u00e9ration explosive de fortes concentrations de thrombine induisant la formation caillot stable.<\/span><\/div>\n
\u00fc\u00a0\u00a0<\/span><\/span><\/span>R\u00e9gulation de la coagulation\u00a0: Extension de la coagulation est pr\u00e9venue par :<\/span><\/div>\n
\u00d8\u00a0\u00a0<\/span><\/span><\/span>le flux sanguin<\/span><\/div>\n
\u00d8\u00a0\u00a0<\/span><\/span><\/span>les propri\u00e9t\u00e9s antithrombotiques de la cellule endoth\u00e9liale.<\/span><\/div>\n
M\u00e9canismes\u00a0<\/span>:<\/span><\/u><\/b><\/div>\n
\u00fc\u00a0\u00a0<\/span><\/span><\/span>Sulfates d\u2019h\u00e9parane de l\u2019endoth\u00e9lium forment un complexe avec AT plasmatique. Ce complexe inhibe les facteurs activ\u00e9s de la coagulation, surtout la thrombine.<\/span><\/div>\n
\u00fc\u00a0\u00a0<\/span><\/span><\/span>Thrombine se lie au r\u00e9cepteur PAR endoth\u00e9lial et induit la production de NO et prostacycline.<\/span><\/div>\n
\u00fc\u00a0\u00a0<\/span><\/span><\/span>Thrombine se fixe \u00e0 la thrombomoduline et active la prot\u00e9ine C plasmatique. La prot\u00e9ine C activ\u00e9e (en pr\u00e9sence de la prot\u00e9ine S, PLP et Ca2+) clive les FVa et FVIIIa qui perdent leurs fonctions cofacteurs.<\/span><\/div>\n
\u00fc\u00a0\u00a0<\/span><\/span><\/span>Complexe Xa-TFPI-Vlla-FT bloque l’activit\u00e9 du FT. (si FT lib\u00e9r\u00e9 est en faible quantit\u00e9).<\/span><\/div>\n
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\u00a0<\/span><\/span><\/div>\n
R\u00c9GULATION DE LA COAGULATION<\/span><\/span><\/span><\/b><\/div>\n
\u00a7\u00a0\u00a0<\/span><\/span><\/span>Permet de limiter l\u2019extension locale du caillot et d\u2019\u00e9viter la diffusion \u00e0 distance de la \ufb01brinoformation.<\/span><\/div>\n
\u00a7\u00a0\u00a0<\/span><\/span><\/span>L\u2019antithrombine ( la vitamine K) est l\u2019un des principaux inhibiteurs physiologiques de la coagulation. Elle neutralise pr\u00e9f\u00e9rentiellement l\u2019activit\u00e9 de la thrombine (IIa) mais aussi celle des autres facteurs de la coagulation (VIIa, IXa, Xa).<\/span><\/div>\n
\u00a7\u00a0\u00a0<\/span><\/span><\/span>Le syst\u00e8me prot\u00e9ine C-prot\u00e9ine S est de d\u00e9couverte plus r\u00e9cente. Il s\u2019agit de deux prot\u00e9ines synth\u00e9tis\u00e9es par le foie sous la d\u00e9pendance de la vitamine K.<\/span><\/div>\n
\u00a7\u00a0\u00a0<\/span><\/span><\/span>La prot\u00e9ine C+ thrombomoduline (membrane endoth\u00e9liale) est activ\u00e9e par la thrombine. La prot\u00e9ine C activ\u00e9e (PCa) en pr\u00e9sence de prot\u00e9ine S neutralise les cofacteurs Va et VIIIa, ralentissant par l\u00e0 consid\u00e9rablement la vitesse de g\u00e9n\u00e9ration de la thrombine. Leurs\u00a0\u00a0<\/span>deficits entrainent un risque accru de thrombose veineuse.<\/span><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/span>\u00a0\u00a0\u00a0<\/span><\/span>Inhibiteurs de la coagulation<\/span><\/span><\/b>
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\n<\/span><\/span><\/b><\/div>\n
\n\n\n\n\n\n\n\n\n\n\n
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Nom<\/span><\/b><\/b><\/div>\n<\/div>\n<\/td>\n
\n
\n
Fonction<\/span><\/b><\/b><\/div>\n<\/div>\n<\/td>\n<\/tr>\n
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Antithrombine<\/span><\/b><\/div>\n<\/div>\n<\/td>\n
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\u00a7\u00a0\u00a0<\/span><\/span><\/span>Inhibe IIa, Xa<\/span><\/div>\n<\/div>\n<\/td>\n<\/tr>\n
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Prot\u00e9ine C<\/span>\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/span><\/span><\/b><\/div>\n<\/div>\n<\/td>\n
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\u00a7\u00a0\u00a0<\/span><\/span><\/span>Inactive Va et VIIIa<\/span><\/div>\n<\/div>\n<\/td>\n<\/tr>\n
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Prot\u00e9ine S<\/span>\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/span><\/span><\/b><\/div>\n<\/div>\n<\/td>\n
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\n
\u00a7\u00a0\u00a0<\/span><\/span><\/span>Cofacteur de prot\u00e9ine C<\/span><\/div>\n<\/div>\n<\/td>\n<\/tr>\n
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\n
Tissue factor pathway inhibitor<\/span>\u00a0(TFPI)\u00a0\u00a0\u00a0\u00a0<\/span><\/span><\/b><\/div>\n<\/div>\n<\/td>\n
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\u00a7\u00a0\u00a0<\/span><\/span><\/span>Inhibe le complexe Facteur tissulaire\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/span><\/span><\/div>\n<\/div>\n
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\u00a7\u00a0\u00a0<\/span><\/span><\/span>Facteur VIIa et Xa<\/span><\/div>\n<\/div>\n<\/td>\n<\/tr>\n
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\n
Inhibiteur d\u00e9pendant de la prot\u00e9ine Z<\/span>\u00a0(ZPI)\u00a0\u00a0 \u00a0<\/span><\/span><\/b><\/div>\n<\/div>\n<\/td>\n
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\u00a7\u00a0\u00a0<\/span><\/span><\/span>Inhibe X et XI.<\/span><\/div>\n<\/div>\n
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<\/div>\n<\/div>\n<\/td>\n<\/tr>\n
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Prot\u00e9ine Z<\/span>\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/span><\/span><\/b><\/div>\n<\/div>\n<\/td>\n
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\n
\u00a7\u00a0\u00a0<\/span><\/span><\/span>Cofacteur de ZPI<\/span><\/div>\n<\/div>\n<\/td>\n<\/tr>\n
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Heparin cofactor II<\/span>\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/span><\/span><\/div>\n<\/div>\n<\/td>\n
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\u00a7\u00a0\u00a0<\/span><\/span><\/span>Inhibe IIa<\/span><\/div>\n<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n
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\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/span><\/b><\/div>\n
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EXPLORATION DE LA COAGULATION<\/span><\/span><\/span><\/b><\/div>\n
\u00a7\u00a0\u00a0<\/span><\/span><\/span>N\u00e9cessaire pour appr\u00e9cier un risque h\u00e9morragique ou thrombotique.<\/span><\/div>\n
\u00a7\u00a0\u00a0<\/span><\/span><\/span>Fait appel \u00e0 un examen clinique et interrogatoire afin de rechercher :<\/span><\/div>\n
\u00fc\u00a0\u00a0<\/span><\/span><\/span>Ant\u00e9c\u00e9dents h\u00e9morragiques ou thrombotiques personnels et familiaux.<\/span><\/div>\n
\u00fc\u00a0\u00a0<\/span><\/span><\/span>Pathologies associ\u00e9es et histoire des h\u00e9morragies ou thromboses (fr\u00e9quence, intensit\u00e9, territoire,\u2026).<\/span><\/div>\n
\u00fc\u00a0\u00a0<\/span><\/span><\/span>H\u00e9morragies :<\/span><\/div>\n
\u2013\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/span><\/span><\/span>H\u00e9matomes de localisation musculaire ou profonde.<\/span><\/div>\n
\u2013\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/span><\/span><\/span>H\u00e9marthroses.<\/span><\/div>\n
\u2013\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/span><\/span><\/span>Retard\u00e9es apr\u00e8s trauma ou chirurgie, volontiers r\u00e9cidivantes.<\/span><\/div>\n
\u00fc\u00a0\u00a0<\/span><\/span><\/span>Thrombophilies constitutionnelles ou acquises.<\/span>
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\n<\/span><\/div>\n
1.\u00a0\u00a0\u00a0\u00a0\u00a0<\/span><\/span><\/span><\/b><\/span>Etape pr\u00e9-analytique<\/span><\/span><\/b>
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\n<\/span><\/b><\/div>\n
\u00a7\u00a0\u00a0<\/span><\/span><\/span>Pr\u00e9l\u00e8vement veineux, achemin\u00e9 au laboratoire sans d\u00e9lai:<\/span><\/div>\n
\u00fc\u00a0\u00a0<\/span><\/span><\/span>Garrot peu serr\u00e9, pos\u00e9 depuis moins d\u2019une minute. Le premier tube pr\u00e9lev\u00e9 ne doit pas \u00eatre celui de l\u2019h\u00e9mostase (activation de l\u2019h\u00e9mostase quand la veine est travers\u00e9 par l\u2019aiguille).<\/span><\/div>\n
\u00fc\u00a0\u00a0<\/span><\/span><\/span>Anticoagulant : citrate trisodique 0,109 M (3,2 %), 1V citrate\/9V sang. Si h\u00e9matocrite\u00a0<30 ou=\u00a0\u00bb\u00a0\u00bb>55%, volume d\u2019anticoagulant doit \u00eatre ajust\u00e9.<\/span><\/div>\n
\u00fc\u00a0\u00a0<\/span><\/span><\/span>Centrifugation \u00e0 2500\/3000g pendant 15 min afin d\u2019obtenir un plasma pauvre en plaquettes :<\/span><\/div>\n
\u00fc\u00a0\u00a0<\/span><\/span><\/span>Il sera utile de r\u00e9aliser une deuxi\u00e8me centrifugation pour certains tests.<\/span><\/div>\n
\u00fc\u00a0\u00a0<\/span><\/span><\/span>Echantillon analys\u00e9 dans les 2 heures, sinon cong\u00e9lation \u00e0 -80\u00b0C.<\/span><\/div>\n
2.\u00a0\u00a0\u00a0\u00a0\u00a0<\/span><\/span><\/span><\/b><\/span>D\u00e9tection m\u00e9canique de la formation du caillot de fibrine\u00a0:<\/span><\/span><\/b>
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3.\u00a0\u00a0\u00a0\u00a0\u00a0<\/span><\/span><\/span><\/b><\/span>Tests de premi\u00e8re intention<\/span><\/span><\/b><\/div>\n
\u00a0<\/span><\/b><\/div>\n
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\u00a7\u00a0\u00a0<\/span><\/span><\/span>Voie endog\u00e8ne et tronc commun sont explor\u00e9s par TCA.<\/span><\/div>\n
\u00a7\u00a0\u00a0<\/span><\/span><\/span>Voie exog\u00e8ne et tronc commun sont explor\u00e9s par Temps de Quick.<\/span>
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\n<\/span><\/div>\n
a.\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/span><\/span><\/span><\/i><\/b>Temps de Quick<\/span><\/u><\/i><\/b><\/span>
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\n<\/span><\/u><\/i><\/b><\/div>\n
\u00a7\u00a0\u00a0<\/span><\/span><\/span>Principe\u00a0<\/span><\/b>: Temps de coagulation \u00e0 37\u00b0C d\u2019un plasma pauvre en plaquette (PPP) recalcifi\u00e9 en pr\u00e9sence d\u2019un exc\u00e8s de thromboplastine.<\/span><\/div>\n
\u00a7\u00a0\u00a0<\/span><\/span><\/span>Indications :<\/span><\/b><\/div>\n
\u00fc\u00a0\u00a0<\/span><\/span><\/span>Bilan pr\u00e9op\u00e9ratoire,<\/span><\/div>\n
\u00fc\u00a0\u00a0<\/span><\/span><\/span>Rechercher un d\u00e9sordre de la voie exog\u00e8ne,<\/span><\/div>\n
\u00fc\u00a0\u00a0<\/span><\/span><\/span>Evaluation du degr\u00e9 d\u2019insuffisance h\u00e9pato-cellulaire,<\/span><\/div>\n
\u00fc\u00a0\u00a0<\/span><\/span><\/span>Surveiller un traitement anticoagulant oral.<\/span><\/div>\n
\u00a7\u00a0\u00a0<\/span><\/span><\/span>Mode op\u00e9ratoire :\u00a0<\/span><\/b>Incubation \u00e0 37\u00b0C du PPP (1V) et de thromboplastine calcique (2V). Constater l\u2019apparition du caillot de fibrine.<\/b><\/span><\/div>\n
\u00a7\u00a0\u00a0<\/span><\/span><\/span>Expression des r\u00e9sultats en:<\/span><\/b><\/div>\n
\u00fc\u00a0\u00a0<\/span><\/span><\/span>Seconde par rapport au temps t\u00e9moin (10-14sec)<\/span><\/div>\n
\u00fc\u00a0\u00a0<\/span><\/span><\/span>Taux de Prothrombine (TP) exprim\u00e9 en %. VN: 70-100%. Cette conversion se fait gr\u00e2ce \u00e0 une droite de Thivolle :\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/span><\/span><\/div>\n
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\u00fc\u00a0\u00a0<\/span><\/span><\/span>INR = [TQ patient\/TQ t\u00e9moin] ISI Utilis\u00e9 pour la surveillance du traitement AVK afin de r\u00e9duire les variations li\u00e9es aux diff\u00e9rentes thromboplastines.<\/span><\/div>\n
INR : International Normalized Ratio, ISI : International Index Sensibility.<\/span>
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\n<\/span><\/div>\n
b.\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/span><\/span><\/span><\/i><\/b>Temps de c\u00e9phaline et activateur (TCA) ou APTT<\/span><\/u><\/i><\/u><\/b><\/span>
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\n<\/span><\/u><\/i><\/b>
\n<\/span><\/u><\/i><\/b><\/div>\n
\u00a7\u00a0\u00a0<\/span><\/span><\/span>Principe :<\/span><\/b>\u00a0Temps de coagulation \u00e0 37\u00b0C d\u2019un PPP recalcifi\u00e9 en pr\u00e9sence de c\u00e9phaline et activateur de la phase contact (Kaolin, acide ellagique).<\/span><\/div>\n
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\u00a7\u00a0\u00a0<\/span><\/span><\/span>Indications :<\/span><\/b><\/div>\n
\u00fc\u00a0\u00a0<\/span><\/span><\/span>Bilan pr\u00e9op\u00e9ratoire.<\/span><\/div>\n
\u00fc\u00a0\u00a0<\/span><\/span><\/span>Rechercher un d\u00e9sordre de la voie intrins\u00e8que ou Ac circulant.<\/span><\/div>\n
\u00fc\u00a0\u00a0<\/span><\/span><\/span>Surveiller un traitement par h\u00e9parine non fractionn\u00e9e.<\/span><\/div>\n
\u00a7\u00a0\u00a0<\/span><\/span><\/span>Mode op\u00e9ratoire<\/span><\/b>\u00a0: Incubation \u00e0 37\u00b0C du PPP (1V) et du m\u00e9lange c\u00e9phaline \/ activateur (1V) pd 2-5 mn selon les r\u00e9actifs. Ajout du CaCl2 (0.025 M, 1V). Constater l\u2019apparition du caillot de fibrine.<\/span><\/div>\n
\u00a7\u00a0\u00a0<\/span><\/span><\/span>Expression des r\u00e9sultats :\u00a0<\/span><\/b>TCA du patient compar\u00e9 au TCA t\u00e9moin. Valeurs normales selon r\u00e9actif et \u00e2ge du patient : Ratio TCA patient \/TCA t\u00e9moin R < 1,2<\/span><\/div>\n
c.\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/span><\/span><\/span><\/i><\/b>\u00a0<\/span>Dosage fonctionnel du fibrinog\u00e8ne<\/span><\/u><\/i><\/b><\/span>
\n
\n<\/span><\/u><\/i><\/b><\/div>\n
\u00a7\u00a0\u00a0<\/span><\/span><\/span>M\u00e9thode chronom\u00e9trique de Von Glauss : mesure le temps de coagulation \u00e0 37\u00b0C d\u2019un PPP du patient dilu\u00e9 en pr\u00e9sence de Ca2+ et d\u2019un exc\u00e8s de thrombine.<\/span><\/div>\n
\u00a7\u00a0\u00a0<\/span><\/span><\/span>Droite de calibration r\u00e9alis\u00e9e \u00e0 l\u2019aide d\u2019un plasma titr\u00e9 en fibrinog\u00e8ne.<\/span><\/div>\n
\u00a7\u00a0\u00a0<\/span><\/span><\/span>VN: 2-4g\/l.<\/span><\/div>\n
4.\u00a0\u00a0\u00a0\u00a0\u00a0<\/span><\/span><\/span><\/b>Tests de seconde intention<\/span><\/b><\/span>
\n
\n<\/span><\/b><\/div>\n
a.\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/span><\/span><\/span><\/i><\/b>Dosage de l\u2019activit\u00e9 des facteurs de coagulation<\/span><\/u><\/i><\/b><\/span>
\n
\n<\/span><\/u><\/i><\/b><\/div>\n
\u00a7\u00a0\u00a0<\/span><\/span><\/span>Droite de calibration.<\/span><\/div>\n
<\/a><\/div>\n
<\/div>\n
<\/div>\n
\u00a7\u00a0\u00a0<\/span><\/span><\/span>M\u00e9lange V \/ V du PPP du patient dilu\u00e9 au 1\/10 ou au 1\/20 et du plasma t\u00e9moin d\u00e9pl\u00e9t\u00e9 en facteur \u00e0 doser.<\/span><\/div>\n
\u00a7\u00a0\u00a0<\/span><\/span><\/span>R\u00e9alisation du TQ pour les dosages des facteurs II, VII, V, X ou du TCA pour les dosages des facteurs VIII, IX, XI, XII.<\/span><\/div>\n
\u00a7\u00a0\u00a0<\/span><\/span><\/span>D\u00e9duire la concentration du facteur sur la droite de calibration.<\/span><\/div>\n
\u2192D\u00e9ficit ou taux \u00e9lev\u00e9 en facteur de la coagulation.<\/span><\/div>\n
b.\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/span><\/span><\/span><\/i><\/b>Activit\u00e9 du FXIII<\/span><\/u><\/i><\/b><\/span>
\n
\n<\/span><\/u><\/i><\/b><\/div>\n
\u00a7\u00a0\u00a0<\/span><\/span><\/span>N\u2019est pas explor\u00e9e par les tests de premi\u00e8re intention.<\/span><\/div>\n
\u00a7\u00a0\u00a0<\/span><\/span><\/span>Devant un syndrome h\u00e9morragique inexpliqu\u00e9, estimation de l\u2019activit\u00e9 du XIII par r\u00e9dissolution du caillot de fibrine par l\u2019acide monochlorac\u00e9tique.<\/span><\/div>\n
c.\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/span><\/span><\/span><\/i><\/b>Etude des syst\u00e8mes inhibiteurs de coagulation<\/span><\/u><\/i><\/b><\/span>
\n
\n<\/span><\/u><\/i><\/b><\/div>\n
\u00a7\u00a0\u00a0<\/span><\/span><\/span>Recherche de la r\u00e9sistance \u00e0 la prot\u00e9ine Ca (APCR).<\/span><\/div>\n
\u00a7\u00a0\u00a0<\/span><\/span><\/span>Dosage de l\u2019activit\u00e9 de l\u2019AT.<\/span><\/div>\n
\u00a7\u00a0\u00a0<\/span><\/span><\/span>Dosage de l\u2019activit\u00e9 de la PC.<\/span><\/div>\n
\u00a7\u00a0\u00a0<\/span><\/span><\/span>Dosage de l\u2019activit\u00e9 de la PS.<\/span><\/div>\n
5.\u00a0\u00a0\u00a0\u00a0\u00a0<\/span><\/span><\/span><\/b>Recherche ACC (anticoagulants circulants):<\/span><\/b><\/span>
\n
\n<\/span><\/b><\/div>\n
\u00a7\u00a0\u00a0<\/span><\/span><\/span>Rechercher si TCA allong\u00e9<\/span><\/div>\n
\u00fc\u00a0\u00a0<\/span><\/span><\/span>Test de correction:<\/span><\/div>\n
\u00d8\u00a0\u00a0<\/span><\/span><\/span>M\u00e9langer volume \u00e0 volume plasma t\u00e9moin + plasma\u00a0\u00a0<\/span>malade<\/span><\/div>\n
\u00d8\u00a0\u00a0<\/span><\/span><\/span>Incubation 2H \u00e0 37\u00b0<\/span><\/div>\n
\u00d8\u00a0\u00a0<\/span><\/span><\/span>Puis mesurer TCA malade, t\u00e9moin et m\u00e9lange<\/span><\/div>\n
\u00d8\u00a0\u00a0<\/span><\/span><\/span><\/span>Calcul indice de Rosner: TCA m\u00e9lange \u2013 TCA t\u00e9moin\u00a0\u00a0<\/span>x 100<\/span><\/div>\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/span>\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/span>TCA malade\u00a0\u00a0<\/span>\u00a0\u00a0\u00a0\u00a0\u00a0<\/span><\/span>\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/span>\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/span><\/span><\/div>\n
\u00d8\u00a0 \u00a0<\/span>>\u00a0<\/span><\/span><\/b><\/span><\/span>15%: ACC+ = pr\u00e9sence d’anticorps circulant<\/span><\/div>\n
\u00d8\u00a0\u00a0<\/span><\/span><\/span>12-15%: Douteux\u00a0 \u00a0 \u00a0 \u00a0\u00a0<\/span>
\n
\n<\/span>\u00a0<\/span>\u00d8<\/span>\u00a0 < 12 % recherche n\u00e9gative<\/span><\/p>\n<\/div>\n<\/div>\n
\u00fc\u00a0\u00a0<\/span><\/span><\/span>Rechercher et titrer l\u2019anticorps.<\/span><\/div>\n
<\/div>\n
6.\u00a0\u00a0\u00a0\u00a0\u00a0<\/span><\/span><\/span><\/b><\/span>Techniques d\u2019exploration de la coagulation<\/span><\/span><\/b>
\n
\n<\/span><\/b><\/div>\n
a.\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/span><\/span><\/span><\/i><\/b><\/span>Chronometrique<\/span><\/span><\/u><\/i><\/b>
\n
\n<\/span><\/u><\/i><\/b><\/div>\n
\u00a7\u00a0\u00a0<\/span><\/span><\/span>Mesure vitesse formation caillot apr\u00e8s ajout r\u00e9actifs d\u00e9clenchants appropri\u00e9s.<\/span><\/div>\n
\u00a7\u00a0\u00a0<\/span><\/span><\/span>Syst\u00e8mes d\u00e9tection caillot:<\/span><\/div>\n
\u00a7\u00a0\u00a0<\/span><\/span><\/span>Manuelle: visuelle<\/span><\/div>\n
\u00a7\u00a0\u00a0<\/span><\/span><\/span>Electromagn\u00e9tique: changement position bille<\/span><\/div>\n
\u00a7\u00a0\u00a0<\/span><\/span><\/span>Optique:\u00a0<\/span>\u00af<\/span>\u00a0intensit\u00e9 lumi\u00e8re transmise<\/span><\/div>\n
\u00a7\u00a0\u00a0<\/span><\/span><\/span>Co\u00fbt\u00a0<\/span>\u00af<\/span><\/div>\n
\u00a7\u00a0\u00a0<\/span><\/span><\/span>Mesure activit\u00e9 catalytique seule.<\/span>
\n
\n<\/span><\/div>\n
b.\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0<\/span><\/span><\/span><\/i><\/b><\/span>Colorimetrique<\/span><\/span><\/u><\/i><\/b>
\n
\n<\/span><\/u><\/i><\/b>
\n<\/span><\/u><\/i><\/b><\/div>\n
\u00a7\u00a0\u00a0<\/span><\/span><\/span>Evaluation activit\u00e9 enzymatique \/substrat\u00a0\u00a0<\/span>chromog\u00e8ne\u00a0\u00a0<\/span>synth\u00e9tique apr\u00e8s clivage de l\u2019enzyme (405nm)<\/span><\/div>\n
\u00a7\u00a0\u00a0<\/span><\/span><\/span>Dosage sp\u00e9cifique facteurs et inhibiteurs<\/span><\/div>\n
\u00a7\u00a0\u00a0<\/span><\/span><\/span>Reproductible<\/span><\/div>\n
\u00a7\u00a0\u00a0<\/span><\/span><\/span>Automatisable<\/span><\/div>\n
\u00a7\u00a0\u00a0<\/span><\/span><\/span>Co\u00fbt<\/span>\u00ad<\/span><\/div>\n
\u00a7\u00a0\u00a0<\/span><\/span><\/span>Mesure activit\u00e9 globale<\/span><\/div>\n
CONCLUSION<\/span><\/span><\/span><\/b><\/div>\n
\u00a7\u00a0\u00a0<\/span><\/span><\/span>Coagulation temps essentiel h\u00e9mostase.<\/span><\/div>\n
\u00a7\u00a0\u00a0<\/span><\/span><\/span>D\u00e9roulement normal\u00a0<\/span>\u00dc<\/span>\u00a0int\u00e9grit\u00e9 tous les composants de l\u2019h\u00e9mostase.<\/span><\/div>\n
\u00a7\u00a0\u00a0<\/span><\/span><\/span>Interpr\u00e9tation bilan d\u2019h\u00e9mostase:<\/span><\/div>\n
\u00fc\u00a0\u00a0<\/span><\/span><\/span>Renseignements cliniques<\/span><\/div>\n
\u00fc\u00a0\u00a0<\/span><\/span><\/span>Bilan biologique complet<\/span><\/div>\n
\u00de<\/span>\u00a0R\u00f4le du\u00a0 biologiste : d\u00e9marche diagnostique \/ anomalie bilan h\u00e9mostase.<\/span><\/div>\n<\/div>\n
Le site www.avo6.com propose un contenu \u00e9ditorial pour pr\u00e9server au mieux sa sant\u00e9. Des conseils et astuces qui vous accompagneront dans votre quotidien autour de la nutrition, les m\u00e9dicaments, beaut\u00e9, les analyses m\u00e9dicales, le bien-\u00eatre et les actualit\u00e9s m\u00e9dicales.<\/div>\n","protected":false},"excerpt":{"rendered":"

\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 GENERALITES Il s\u2019agit du processus de coagulation du plasma sanguin aboutissant \u00e0 la transformation…<\/p>\n","protected":false},"author":2,"featured_media":394,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"om_disable_all_campaigns":false,"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"footnotes":""},"categories":[2],"tags":[],"class_list":["post-26","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-hematologie","entry"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/avo6.com\/index.php?rest_route=\/wp\/v2\/posts\/26","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/avo6.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/avo6.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/avo6.com\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/avo6.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=26"}],"version-history":[{"count":1,"href":"https:\/\/avo6.com\/index.php?rest_route=\/wp\/v2\/posts\/26\/revisions"}],"predecessor-version":[{"id":395,"href":"https:\/\/avo6.com\/index.php?rest_route=\/wp\/v2\/posts\/26\/revisions\/395"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/avo6.com\/index.php?rest_route=\/wp\/v2\/media\/394"}],"wp:attachment":[{"href":"https:\/\/avo6.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=26"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/avo6.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=26"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/avo6.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=26"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}