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Haemorrhagic Disease Pathophysiology (view source)
Revision as of 11:19, 6 October 2010
, 11:19, 6 October 2010Created page with "==Introduction== Haemorrhagic diseases can be categorised into two different causal mechanisms: *Increased vessel fragility which leads to a non-thrombocytopenic purpura. *Inadeq..."
==Introduction==
Haemorrhagic diseases can be categorised into two different causal mechanisms:
*Increased vessel fragility which leads to a non-thrombocytopenic purpura.
*Inadequate haemostatic response. This may be caused by platelet dysfunction or deficiency, which leads to a primary or secondary thrombocytopenic purpura, or deficiencies/derangements of clotting factors.
Syndromes caused by vascular fragility and platelet dysfunction tend to be purpuric and acquired.
Syndromes caused by clotting factor defects tend to cause more severe bleeding and are usually congenital.
==Vascular Fragility==
There are several ways that vascular fragility may arise. Capillaries can be damaged 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]] would be good examples of organisms that feature capillary damage as a symtom of infection.
Drug-induced damage to the vascular system does occur, although 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 and salicylates.
Vascular fragility can occur as a consequence of an underlying disease state, which is seen in allergy or anaphylactic reactions, connective tissue diseases such as Ehlers-Danlos syndrome in dogs, [[DM|Diabetes mellitus]] and antibody-antigen complex reactions.
==Platelet dysfunction==
==Clotting Factor Abnormalities==
[[Category:Haemorrhagic Diseases|A]]
[[Category:To Do - Blood]]
Haemorrhagic diseases can be categorised into two different causal mechanisms:
*Increased vessel fragility which leads to a non-thrombocytopenic purpura.
*Inadequate haemostatic response. This may be caused by platelet dysfunction or deficiency, which leads to a primary or secondary thrombocytopenic purpura, or deficiencies/derangements of clotting factors.
Syndromes caused by vascular fragility and platelet dysfunction tend to be purpuric and acquired.
Syndromes caused by clotting factor defects tend to cause more severe bleeding and are usually congenital.
==Vascular Fragility==
There are several ways that vascular fragility may arise. Capillaries can be damaged 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]] would be good examples of organisms that feature capillary damage as a symtom of infection.
Drug-induced damage to the vascular system does occur, although 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 and salicylates.
Vascular fragility can occur as a consequence of an underlying disease state, which is seen in allergy or anaphylactic reactions, connective tissue diseases such as Ehlers-Danlos syndrome in dogs, [[DM|Diabetes mellitus]] and antibody-antigen complex reactions.
==Platelet dysfunction==
==Clotting Factor Abnormalities==
[[Category:Haemorrhagic Diseases|A]]
[[Category:To Do - Blood]]