Thrombosis

Casual Factors
1. Virchows Triad
  1. 1) Endothelial Injury
    1. Viruses
      1. Bacteria
        Fungi
        Toxins
        Immune mediated vasculitis
        Disseminated Intravascular Coagulation (DIC)
        Local extension of Infection
        Intravenous Injections or indwelling catheters
        Purpura Haemorrhagica (Horses with Strep. equi infection)
        Strongylus vulgaris larvae
        Aspergillus
        Salmonella typhimurium, erysipelothrix
      2. Canine adenovirus, Equine herpesvirus
  2. 2) Abnormal Blood Flow
    1. Heart disease or Hypovolemia
      1. Systemic reduction in blood flow
        Ex. Dilated cardiomyopathy
    2. Local reduced flow/stasis
      1. Gastric dilatation & volvulus
        Stomach swells and twists
        Restricts blood flow
        Hypoxia + Stasis => Platelet deposition
      2. Turbulence
        Valvular disease
        Aneurysm
  3. 3) Hypercoagulability
    1. Enhanced platelet activity
      1. E..g. Diabetes mellitus, Nephrotic syndrome, Malignant neoplasia
    2. Increased clotting factor activation
      1. Ex. DIC
    3. Metabolic abnormalities
      1. E.g. Hyperadrenocorticism
    4. Glomerulopathies
      1. Loss of Anti-thrombin III in urine
Thrombi
1. Composition
  1. Mainly fibrin + Platelets
    1. Pale color:
  2. Mainly fibrin + RBCs
    1. Red color:
  3. Layers of RBC + WBC + fibrin
    1. Laminated:
2. Location
  1. Mural/Parietal
    1. Occluding
      1. Consecutive
        Blood backed up behind clot
      2. As thrombi progress => May block the lumen
    2. Attached to the vessel wall & do not occlude the lumen
3. Nature
  1. "Bland"
    1. Blood constituents only
  2. Infective
    1. + Bacteria
  3. Parasitic
    1. + Larvae
  4. Neoplastic
    1. + Tumor cells
Consequences
1. Importance of initial thrombus depends on:
  1. 1) Location of formation
    1. Arterial, Venous, Cardiac (Ischaemia & Hypoxic damage
  2. 2) Nature
    1. Bland
      1. Infective
        Neoplastic
        Metastasis
        Bacteria
        Abscess
  3. 3) Rate of Formation
    1. Rapid development of Thrombus leaves no time for compensation by collateral circulation
      1. Ex. Pulmonary Thrombi
Fate
1. Dissolution
  1. Removed by fibrinolysis
  2. Small or recently formed
2. Propagation &/or Embolisation
  1. Spread around body as bits break off
3. Organization & Recanalisation
  1. Scar tissue & Get lumen of vessel back again

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Thrombosis

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	Created by melian.yates over 10 years ago