haemostatics n.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
Haemostatics PowerPoint Presentation
Download Presentation
Haemostatics

Loading in 2 Seconds...

play fullscreen
1 / 14

Haemostatics - PowerPoint PPT Presentation


  • 57 Views
  • Uploaded on

Haemostatics. Virchow’s Triad. Hypercoagulable state. Stasis/turbulence. Endothelial injury. Clotting Processes. 1) Vascular Phase (immediate): Transient vasoconstriction Exposure of underlying subendothelium Local factors. Clotting Processes (cont.). 2) Platelet Phase (15 sec):

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Haemostatics' - ogden


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
virchow s triad
Virchow’s Triad

Hypercoagulable state

Stasis/turbulence

Endothelial injury

clotting processes
Clotting Processes

1) Vascular Phase (immediate):

  • Transient vasoconstriction
  • Exposure of underlying subendothelium
  • Local factors
clotting processes cont
Clotting Processes (cont.)

2) Platelet Phase (15 sec):

  • Adhesion to subendothelium (mediated by von Willebrand factor)
  • Secretion of chemicals (5-TAPP)
    • 5HT: promotes vasoconstriction
    • Thromboxane A2: ↑ platelet aggregation
    • Adenosine diphosphate: activates GpIIb/IIIa to ↑ platelet binding
    • PAF (platelet activating factor): ↑ platelet aggregation
    • Plasminogen: localises clot formation at injury site

*Aspirin, Dipyridamole

*Clopidogrel, dipyridamole

*Fibrinolytics (streptokinase, urokinase)

clotting processes cont1
Clotting Processes (cont.)

3) Coagulation Phase:

Extrinsic Pathway: Exposure to Tissue Factor

Intrinsic Pathway: Exposure to collagen/glass

XIIa

XII

VII

VIIa + TF

XI

XIa

IX

IXa

X

Xa

VIII

VIIIa

XIII

XIIIa

II

IIa (thrombin)

V

Va

I

Ia (fibrin)

  • Warfarin blocks II, VII, IX, X (TV Channels)
  • Heparins activate III  blocks Iia and Xa (low molecular weight heparins especially blocks Xa)
  • Dabigatran blocks II (thrombin). Is currently trialed as a less fussy (wrt interactions and monitoring) alternative to warfarin
clotting processes cont2
Clotting Processes (cont.)
  • Coagulation Limiters: restricted to sites of exposed phospholipids
    • Antithrombin III: blocks IIa, Ixa, Xa, XIa and XIIa
    • Protein C: inactivates V, VIII
      • Protein S is a cofactor for Protein C
      • Protein C is activated by thrombin (IIa)
    • Tissue Factor Pathway Inhibitor (TFPI): blocks Xa, IIa
haemostasis in bruises
Haemostasis in Bruises
  • Types of bruises:
    • Damaged vessels (e.g. trauma, vasculitis)
    • Changes in blood (e.g. thrombocytopaenia)
    • Changes in dermis (e.g. senile purpura, scurvy)
  • Bruise = blood vessel damage that causes leaking into surrounding connective tissue
  • Petechiae are a type of bruising (a tiny red-purple spot; purpura and ecchymosesare similar but are larger)
  • Not to be confused with telangiectasia(capillary dilatation, e.g. from old age, steroid use, irradiation, liver failure)
slide12

Purpura – large red-purple spots (>10mm)

Petechiae – tiny red-purple spots (<3mm)

Telangiectasia – dilated capillary network

Purpura – bigger red-purple spots (3-10mm)

relevance to dengue fever
Relevance to Dengue Fever
  • The patient had petechiae
  • The petechiae are possibly a result of thrombocytopaenia or platelet dysfunction  makes it easier to break capillaries
  • Capillary vasodilationin critical phase could potentially worsen symptoms by increasing bleeding
references
References
  • Sherwood. Human Physiology 6th edition
  • Rang and Dale’s Pharmacology
  • Cross and Underwood. General Systemic Pathology
  • Kuma. Robbins and Cotran Pathologic Basis of Disease, Professional Edition , 8th ed
  • AMH
  • Therapeutic Guidelines
  • Australian Prescriber: http://www.australianprescriber.com/magazine/32/2/51/5