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Category:Haemorrhagic Diseases (view source)
Revision as of 15:41, 10 August 2010
, 15:41, 10 August 2010Created page with "* There is a wide range of diseases and syndromes that are characterised by haemorrhagic disease. * Show either: ** An increased tendency to bleeding - haemorrhagic diathesis. **..."
* 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 - [[Haemorrhage - Pathology#Purpura|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
*# '''Increased vessel fragility'''.
*#* Causes non-thrombocytopenic purpura.
*# '''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.
=== Haemorrhagic Disease Due To Vascular Fragility===
* There are several ways that vascular fragility may arise.
# Capillary damage by toxins.
#* This occurs in severe bacterial infections in all species.
#* [[:Category:Streptococcus species|''Streptococcus'']] and [[:Category:Pasteurella and Mannheimia species|''Pasteurella'']] infections and [[Bacillus species|anthrax]] can all cause this.
# Drug-induced damage.
#* The mechanisms of damage induced by drugs are not clearly understood.
#* Examples include:
#** Heavy metals, e.g. lead, bismuth, mercury.
#** Iodides.
#** Fluorides.
#** Chlorinated hydrocarbon pesticides.
#** Salicylates.
# Other miscellaneous causes:
#* Allergy or anaphylactic responses.
#* Connective tissue disease.
#** E.g. Ehlers-Danlos syndrome in dogs.
#* [[DM|Diabetes mellitus]].
#* Antibody-antigen complex reaction.
===Disease associated with platelet abnormalities===
====Primary Thrombocytopenic Disease====
* The aetiology of primary thrombocytopenic disease is often uncertain.
** It is therefore also known as idiopathic thrombocytopenia.
** The cause may be automimmune.
* Although the [[Bone Marrow - Anatomy & Physiology|bone marrow]] contains adequate normal megakaryocytes, there is a reduced peripheral blood thrombocyte count.
* Usually seen in young animals.
====Secondary Thrombocytopenic Disease====
* Secondary thrombocyopaenic disease is fairly common in adult and older domestic animals.
* Associated with diseases which cause [[Bone Marrow - Anatomy & Physiology|bone marrow]] depression.
* The [[Bone Marrow - Anatomy & Physiology|bone marrow]] is depleted or devoid of megakaryocytes, and there is a nil or markedly reduced peripheral blood thrombocyte count.
* Secondary thrombocyopenic disease is seen in the following conditions:
*# Severe viral infections.
*#* For examople, ICH, feline panleucopenia, [[Bovine Viral Diarrhoea Virus|mucosal disease]], [[Classical Swine Fever|swine fever]].
*# Severe protozoal infections.
*#* For example, in the UK, Haemobartonella may be a cause.
*# Plant intoxications.
*#* For example, bracken, kale, or ragwort poisoning.
*# Drug-induced conditions.
*#* High doses of oestrogens and salicylate.
*#* Prolonged use of phenyl butazone.
*# [[Bone Marrow - Anatomy & Physiology|bone marrow]] neoplasia.
*#* For example, lymphosarcoma or myeloid leukaemia.
*# Radiation.
*#* May cause damage to the [[Bone Marrow - Anatomy & Physiology|bone marrow]] if it is severe and generalised.
*# Other miscellaneous causes.
*#* Severe bacterial infections.
*#** For example, [[:Category:Staphylococcus species|''Staphylococci'']], and those Gram -ve bacteria producing endotoxins (e.g. [[:Category:Pseudomonas and Burkholderia species|''Pseudomonas'']] or [[Salmonella|''Salmonella'']] spp.).
*#* [[Liver - Anatomy & Physiology|Liver]] disease.
====Thrombocytopathia====
* A rare inherited condition.
* Recorded in the dog.
* Characterised by defective thrombocyte formation.
** Poor adhesiveness.
** Poor aggregations.
** Poor platelet factor release.
===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]]
* Show either:
** An increased tendency to bleeding - haemorrhagic diathesis.
** Frank haemorrhages as a clinical feature - [[Haemorrhage - Pathology#Purpura|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
*# '''Increased vessel fragility'''.
*#* Causes non-thrombocytopenic purpura.
*# '''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.
=== Haemorrhagic Disease Due To Vascular Fragility===
* There are several ways that vascular fragility may arise.
# Capillary damage by toxins.
#* This occurs in severe bacterial infections in all species.
#* [[:Category:Streptococcus species|''Streptococcus'']] and [[:Category:Pasteurella and Mannheimia species|''Pasteurella'']] infections and [[Bacillus species|anthrax]] can all cause this.
# Drug-induced damage.
#* The mechanisms of damage induced by drugs are not clearly understood.
#* Examples include:
#** Heavy metals, e.g. lead, bismuth, mercury.
#** Iodides.
#** Fluorides.
#** Chlorinated hydrocarbon pesticides.
#** Salicylates.
# Other miscellaneous causes:
#* Allergy or anaphylactic responses.
#* Connective tissue disease.
#** E.g. Ehlers-Danlos syndrome in dogs.
#* [[DM|Diabetes mellitus]].
#* Antibody-antigen complex reaction.
===Disease associated with platelet abnormalities===
====Primary Thrombocytopenic Disease====
* The aetiology of primary thrombocytopenic disease is often uncertain.
** It is therefore also known as idiopathic thrombocytopenia.
** The cause may be automimmune.
* Although the [[Bone Marrow - Anatomy & Physiology|bone marrow]] contains adequate normal megakaryocytes, there is a reduced peripheral blood thrombocyte count.
* Usually seen in young animals.
====Secondary Thrombocytopenic Disease====
* Secondary thrombocyopaenic disease is fairly common in adult and older domestic animals.
* Associated with diseases which cause [[Bone Marrow - Anatomy & Physiology|bone marrow]] depression.
* The [[Bone Marrow - Anatomy & Physiology|bone marrow]] is depleted or devoid of megakaryocytes, and there is a nil or markedly reduced peripheral blood thrombocyte count.
* Secondary thrombocyopenic disease is seen in the following conditions:
*# Severe viral infections.
*#* For examople, ICH, feline panleucopenia, [[Bovine Viral Diarrhoea Virus|mucosal disease]], [[Classical Swine Fever|swine fever]].
*# Severe protozoal infections.
*#* For example, in the UK, Haemobartonella may be a cause.
*# Plant intoxications.
*#* For example, bracken, kale, or ragwort poisoning.
*# Drug-induced conditions.
*#* High doses of oestrogens and salicylate.
*#* Prolonged use of phenyl butazone.
*# [[Bone Marrow - Anatomy & Physiology|bone marrow]] neoplasia.
*#* For example, lymphosarcoma or myeloid leukaemia.
*# Radiation.
*#* May cause damage to the [[Bone Marrow - Anatomy & Physiology|bone marrow]] if it is severe and generalised.
*# Other miscellaneous causes.
*#* Severe bacterial infections.
*#** For example, [[:Category:Staphylococcus species|''Staphylococci'']], and those Gram -ve bacteria producing endotoxins (e.g. [[:Category:Pseudomonas and Burkholderia species|''Pseudomonas'']] or [[Salmonella|''Salmonella'']] spp.).
*#* [[Liver - Anatomy & Physiology|Liver]] disease.
====Thrombocytopathia====
* A rare inherited condition.
* Recorded in the dog.
* Characterised by defective thrombocyte formation.
** Poor adhesiveness.
** Poor aggregations.
** Poor platelet factor release.
===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]]