Difference between revisions of "Category:Haemorrhagic Diseases"

From WikiVet English
Jump to navigation Jump to search
Line 23: Line 23:
  
  
===Diseases associated with coagulation factor defects===
 
 
* Most cases of "factor disease" in animals are similar to those studied in man.
 
** Congenital.
 
** Based on familial occurence.
 
** Clotting biochemistry is similar in man and animals.
 
* Most investigations have been carried out in the dog.
 
* [[Haemostasis - Pathology#Factor VIII|Haemophilia]] (factor VIII deficiency) is probably the best understood condition.
 
 
====Von Willebrand's Disease====
 
 
* Seen in the dog.
 
** Most common in Scottish Terriers and Chesapeake Bay Retrievers.
 
** Has been seen more recently in Dobermanns, Setters and German Shepherd dogs. 
 
** A similar disease has been recorded in the pig. 
 
* Von Willebrand's Disease is an inherited autosomal recessive trait.
 
** It is incompletely dominant, so there is variable expression.
 
* '''Presentation'''
 
** Purpura.
 
** Prolonged bleeding time.
 
** Reduced platelet adhesiveness.
 
** Low Factor XIII levels.
 
* The disease can be assessed by the measurement of Von Willebrand Factor protein levels.
 
** A Factor VIII-related protein.
 
** Synthesised in endothelial cells and megakaryocytes.
 
** Stored in platelets. 
 
** Levels are low in affected animals.
 
 
 
 
'''Deficiency states of other factors have been recorded sporadically as follows:'''
 
 
====Factor I ====
 
 
* Factor 1 is fibrinogen.
 
* '''Hyperfibrinogenaemia''' occurs in
 
** Pregnancy
 
** Acute infections
 
** Post-operative states
 
** Pyometra
 
* '''Hypofibrinogenaemia''' is seen in
 
** Liver disease.
 
** Depletion by intravascular coagulation.
 
 
====Factor II ====
 
 
* Factor II is part of the prothrombin complex.
 
* '''Hypoprothrombinaemia'''
 
** A depression of the components of the prothrombin complex.
 
*** I.e. Factors II, VII, IX, X
 
** May be caused by dicoumarol and its derivatives, for example sweet clover and warfarin.
 
*** Competitively inhibits Vitamin K  in the liver, where the above Factors are synthesised.
 
 
====Factor IV ====
 
 
* Factor IV is calcium.
 
** Necessary at several stages of coagulation. 
 
* '''Hypocalcaemia''' at a level sufficient to impair haemostasis is incompatible with life.
 
** There is therefore no bleeding defect associated with hypocalcaemia.
 
 
====Factor VII====
 
 
* Factor VII is Proconvertin.
 
* Deficiencies do not appear to impair the formation of haemostatic plug.
 
** The bleeding defect is normally mild.
 
* Newborn pups have a very low plasma level of Factor VII.
 
** Spontaneous and inherited deficiencies have been reported in Beagle colonies.
 
* Deficiencies may also occur associated with [[Liver - Anatomy & Physiology|liver]] disease and in dicoumarol poisoning.
 
 
====Factor VIII ====
 
 
* Factor VIII is known as antihaemophilic factor (AHF).
 
* Deficiency of this factor causes '''haemophilia A'''.
 
** The primary thrombocyte plug is abnormal.
 
*** More vascular channels than usual.
 
*** Less fibrin-collagen contact around the edges. 
 
** Plugs are therefore easily dislodged.
 
*** Results in rebleeding.
 
*** Secondary plugs only form with difficulty. 
 
* Haemophilia is reported in horses and in around 20 breeds of dogs.
 
* Haemophilia is as a sex-linked recessive condition.
 
** Associated with the X chromosome.
 
** Affects males only.
 
* The severity of the disease correlates with the Factor VIII levels.
 
* Haematomas and haemarthrosis are common lesions.
 
 
====Factor IX ====
 
 
* Factor IX is Christmas Factor.
 
* Deficiency causes '''haemophilia B'''.
 
** Seen in Cairn Terriers and Black and Tan Hounds.
 
** A sex-linked (X chromosome) recessive.
 
** Results in a deficient haemostatic plug.
 
*** Similar to Factor VIII deficiency.
 
 
====Factor XI====
 
 
* Factore XI is Plasma Thromboplastin Antecedent.
 
* Deficiency has been reported in a cow, and reduced levels in the horse.
 
 
====Factor XII====
 
 
* Factor XII is Hageman Factor.
 
* Low plasma levels had been reported in cats and horses.
 
  
 
[[Category:Haemostasis - Pathology]]
 
[[Category:Haemostasis - Pathology]]

Revision as of 15:46, 10 August 2010

  • There is a wide range of diseases and syndromes that are characterised by haemorrhagic disease.
  • Show either:
    • An increased tendency to bleeding - haemorrhagic diathesis.
    • Frank haemorrhages as a clinical feature - purpura.
  • Altought this disease is sometimes obvious, it may also be discovered incidentally, for examply following surgery or trauma.

Classification of Haemorrhagic Diseases

  • Haemorrhagic diseases may be due to
    1. Increased vessel fragility.
      • Causes non-thrombocytopenic purpura.
    2. Inadequate haemostatic response.
      • This may be caused by:
        • Platelet dysfunction or deficiency.
          • Causes primary or secondary thrombocytopenic purpura.
        • Deficiencies or derangements of clotting factors.
  • Syndromes caused by vascular fragility and platelet dysfunction tend to be purpuric and aquired.
  • Sydromes caused by clotting factor defects tend to cause more severe bleeding and are usually congenital.

Vascular Fragility

Platelet Abnormalities

Pages in category "Haemorrhagic Diseases"

The following 4 pages are in this category, out of 4 total.