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Coagulation Factor Deficiency (view source)
Revision as of 15:46, 10 August 2010
, 15:46, 10 August 2010no edit summary
** Often seen as familial inherited problems.
** Often seen as familial inherited problems.
*** E.g. haemophilia
*** E.g. haemophilia
===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:Coagulation Defects]]
[[Category:Coagulation Defects]]
[[Category:Haemorrhagic Diseases]]