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New page: {{review}} {{toplink |linkpage =General Pathology |linktext =General Pathology |maplink = General Pathology (Content Map) |pagetype =Pathology |sublink1=Circulatory Disorders - Pathology ...
{{review}}
{{toplink
|linkpage =General Pathology
|linktext =General Pathology
|maplink = General Pathology (Content Map)
|pagetype =Pathology
|sublink1=Circulatory Disorders - Pathology
|subtext1=CIRCULATORY DISORDERS
}}
<br>
==Introduction==
* Haemorrhage is the escape of blood from within the cardiovascular system.
* Can be distinguished microscopically from congestion.
** Congestion - the blood remains within the vessels.
** Haemorrhage - blood is seen outside the vessels.
* Haemorrhage may be of capillary, venous, arterial and rarely cardiac origin.
* May be external or internal (within body cavities).
* Associated with:
** Wounds or trauma.
** Inflammation, where toxins are involved.
** Neoplastic disease.
* "Haemorrhagic diathesis" describes a predisposition to bleeding, either spontaneous or associated with trifling mechanical damage.
** Often manifests as [[Haemorrhage - Pathology#Purpura|purpuric disease]].
** Haemorrhagic diatheses and [[Haemorrhage - Pathology#Purpura|purpura]] may be a feature of a number of diseases of different aetiology (poisoning, septicaemia or neoplastic disease).
==Types of Haemorrhage==
* Two main types of haemorrhage are recognised and are considered in more detail below:
** '''[[Haemorrhage - Pathology#Haemorrhage by Rhexis|Rhexis]]'''
*** Actual physical rupture of a vessel wall
** '''[[Haemorrhage - Pathology#Haemorrhage by Diapedesis|Diapedesis]]'''
*** The escape of blood from vessels.
*** It may be difficult to detect a disruption to the vessel wall.
===Haematoma===
* A large blood clot within the tissues.
** A localised collection of blood confined by surrounding tissues resulting in a modular formation.
*Often sub-cutaneous.
* May form space-occupying lesions.
** E.g. in brain.
===In Body Cavities===
* Haemothorax, Haemopericardium and Haemoperitoneum.
** Blood escapes into the respective body cavities.
===Petechiae===
* These are minute - foci are 1-2mm in diameter.
* Of capillary origin.
* Usually seen on the skin, mucous membranes and serosal surfaces.
===Ecchymoses===
* Of capillary origin. .
* Foci are 3-23mm in diameter.
* Are blotchy.
* Often confluent.
* Usually seen on the skin, mucous membranes and serosal surfaces.
===Purpura===
* Purpura is a clinical syndrome.
* Multiple small spontaneous haemorrhages develop in tissues (e.g. skin, mucosae, serosal surfaces and joints).
* A mixture of petechiae and ecchymoses.
==Haemorrhage by Rhexis==
* This is of venular or arteriolar (or larger vessel) origin.
** Results in major bleeding.
* There are several causes of haemorrhage by rhexis.
** Trauma.
** Haemorrhagic enteritis.
** Erosion of blood vessels by tumours or abscesses.
** Idiopathic rupture of arteries.
* In the horse intrapericardial rupture of the aorta may occur, although this is uncommon.
==Haemorrhage by Diapedesis==
===Septicaemia===
* Causes large numbers of petechiae and ecchymoses.
===Toxaemia and Poisoning===
* Causes petechiae and ecchymoses.
** These haemorrhages are probably due to direct damage to the vessel walls.
===Purpura haemorrhagica===
* Pupura haemorrhagica is a condition that occurs in horses after an infection.
** Particularly following [[Respiratory Bacterial Infections - Pathology#Strangles|Strangles]].
* Endothelial damage is caused by accumulation of immune complexes.
===Haemophilia===
* Failure of the normal clotting of the blood.
** Due to absence of one of the clotting factors.
* Rare.
* Reported in dogs and pigs.
===Dicoumeral poisoning===
* Dicoumeral is an antagonist to Vitamin K.
** Vitamin K is needed by the liver to synthesise prothrombin and various clotting factors.
*Occurs with:
** Warfarin poisoning
*** Warfarin is a common rat poison)
** Prolonged feeding of sweet clover.
==Gross Appearance of Haemorrhage==
* The gross appearance of haemorrhage can vary depending on the tissue in which it occurs.
===Epistaxis===
* Epistaxis is a nose bleed.
* The haemorrhage may originate anywhere in the respiratory system.
* Can occur in the lungs following heavy exercise in the horse.
** Appears bright red and perhaps frothy.
===Gastric Haemorrhage===
* Gastric secretion soon turns the blood a dark brown.
* When vomited up it is called Haematomesis.
* Blood originating in the stomach and upper small intestine that is passed through the anus and is called Melena.
===Dysentery===
* Occurs when the bleeding is low down the [[Alimentary - Anatomy & Physiology|alimentary tract]].
* The blood is passed in the faeces relatively unchanged.
===Haematuria===
* Blood is present in the urine.
** Imparts a red colour to it.
*It is important to distinguish this from haemoglobinuria.
** In haemoglobinuria, the breakdown products of red blood cells appear in the urine following intravascular haemolysis.
** In haemorrhage, the red blood cells will separate out and sediment to the bottom of a test tube.
===Bruising===
* Brusing is the result of haemorrhage.
* Appears red for 48 hours and then begins to turn yellow.
** Due to macrophages converting haemoglobin into haemosiderin.
==Effects of Haemorrhage==
===Local===
* Haemorrhage may result in a diffuse mass of red blood cells and fibrin in loose connective tissues and in organs.
** E.g. in the cutaneous connective tissues, the [[Spleen - Anatomy & Physiology|spleen]] and the gut wall.
* Alternatively, a local accumulation may form a haematoma and become a space- occupying lesion.
** This may interfere with organ function.
*** E.g in intracranial haemorrhage, haemopericardium, and pulmonary haemorrhage.
===Systematic===
* The systematic effects of haemorrhage are usually associated with uncontrolled blood loss.
** I.e. from a major artery associated with trauma.
* Rate of loss is critical, e.g.
** Loss of 30-40 per cent in a few minutes is often fatal.
** Loss of over 50% over a 24 period may be tolerated in the dog.
{{toplink
|linkpage =General Pathology
|linktext =General Pathology
|maplink = General Pathology (Content Map)
|pagetype =Pathology
|sublink1=Circulatory Disorders - Pathology
|subtext1=CIRCULATORY DISORDERS
}}
<br>
==Introduction==
* Haemorrhage is the escape of blood from within the cardiovascular system.
* Can be distinguished microscopically from congestion.
** Congestion - the blood remains within the vessels.
** Haemorrhage - blood is seen outside the vessels.
* Haemorrhage may be of capillary, venous, arterial and rarely cardiac origin.
* May be external or internal (within body cavities).
* Associated with:
** Wounds or trauma.
** Inflammation, where toxins are involved.
** Neoplastic disease.
* "Haemorrhagic diathesis" describes a predisposition to bleeding, either spontaneous or associated with trifling mechanical damage.
** Often manifests as [[Haemorrhage - Pathology#Purpura|purpuric disease]].
** Haemorrhagic diatheses and [[Haemorrhage - Pathology#Purpura|purpura]] may be a feature of a number of diseases of different aetiology (poisoning, septicaemia or neoplastic disease).
==Types of Haemorrhage==
* Two main types of haemorrhage are recognised and are considered in more detail below:
** '''[[Haemorrhage - Pathology#Haemorrhage by Rhexis|Rhexis]]'''
*** Actual physical rupture of a vessel wall
** '''[[Haemorrhage - Pathology#Haemorrhage by Diapedesis|Diapedesis]]'''
*** The escape of blood from vessels.
*** It may be difficult to detect a disruption to the vessel wall.
===Haematoma===
* A large blood clot within the tissues.
** A localised collection of blood confined by surrounding tissues resulting in a modular formation.
*Often sub-cutaneous.
* May form space-occupying lesions.
** E.g. in brain.
===In Body Cavities===
* Haemothorax, Haemopericardium and Haemoperitoneum.
** Blood escapes into the respective body cavities.
===Petechiae===
* These are minute - foci are 1-2mm in diameter.
* Of capillary origin.
* Usually seen on the skin, mucous membranes and serosal surfaces.
===Ecchymoses===
* Of capillary origin. .
* Foci are 3-23mm in diameter.
* Are blotchy.
* Often confluent.
* Usually seen on the skin, mucous membranes and serosal surfaces.
===Purpura===
* Purpura is a clinical syndrome.
* Multiple small spontaneous haemorrhages develop in tissues (e.g. skin, mucosae, serosal surfaces and joints).
* A mixture of petechiae and ecchymoses.
==Haemorrhage by Rhexis==
* This is of venular or arteriolar (or larger vessel) origin.
** Results in major bleeding.
* There are several causes of haemorrhage by rhexis.
** Trauma.
** Haemorrhagic enteritis.
** Erosion of blood vessels by tumours or abscesses.
** Idiopathic rupture of arteries.
* In the horse intrapericardial rupture of the aorta may occur, although this is uncommon.
==Haemorrhage by Diapedesis==
===Septicaemia===
* Causes large numbers of petechiae and ecchymoses.
===Toxaemia and Poisoning===
* Causes petechiae and ecchymoses.
** These haemorrhages are probably due to direct damage to the vessel walls.
===Purpura haemorrhagica===
* Pupura haemorrhagica is a condition that occurs in horses after an infection.
** Particularly following [[Respiratory Bacterial Infections - Pathology#Strangles|Strangles]].
* Endothelial damage is caused by accumulation of immune complexes.
===Haemophilia===
* Failure of the normal clotting of the blood.
** Due to absence of one of the clotting factors.
* Rare.
* Reported in dogs and pigs.
===Dicoumeral poisoning===
* Dicoumeral is an antagonist to Vitamin K.
** Vitamin K is needed by the liver to synthesise prothrombin and various clotting factors.
*Occurs with:
** Warfarin poisoning
*** Warfarin is a common rat poison)
** Prolonged feeding of sweet clover.
==Gross Appearance of Haemorrhage==
* The gross appearance of haemorrhage can vary depending on the tissue in which it occurs.
===Epistaxis===
* Epistaxis is a nose bleed.
* The haemorrhage may originate anywhere in the respiratory system.
* Can occur in the lungs following heavy exercise in the horse.
** Appears bright red and perhaps frothy.
===Gastric Haemorrhage===
* Gastric secretion soon turns the blood a dark brown.
* When vomited up it is called Haematomesis.
* Blood originating in the stomach and upper small intestine that is passed through the anus and is called Melena.
===Dysentery===
* Occurs when the bleeding is low down the [[Alimentary - Anatomy & Physiology|alimentary tract]].
* The blood is passed in the faeces relatively unchanged.
===Haematuria===
* Blood is present in the urine.
** Imparts a red colour to it.
*It is important to distinguish this from haemoglobinuria.
** In haemoglobinuria, the breakdown products of red blood cells appear in the urine following intravascular haemolysis.
** In haemorrhage, the red blood cells will separate out and sediment to the bottom of a test tube.
===Bruising===
* Brusing is the result of haemorrhage.
* Appears red for 48 hours and then begins to turn yellow.
** Due to macrophages converting haemoglobin into haemosiderin.
==Effects of Haemorrhage==
===Local===
* Haemorrhage may result in a diffuse mass of red blood cells and fibrin in loose connective tissues and in organs.
** E.g. in the cutaneous connective tissues, the [[Spleen - Anatomy & Physiology|spleen]] and the gut wall.
* Alternatively, a local accumulation may form a haematoma and become a space- occupying lesion.
** This may interfere with organ function.
*** E.g in intracranial haemorrhage, haemopericardium, and pulmonary haemorrhage.
===Systematic===
* The systematic effects of haemorrhage are usually associated with uncontrolled blood loss.
** I.e. from a major artery associated with trauma.
* Rate of loss is critical, e.g.
** Loss of 30-40 per cent in a few minutes is often fatal.
** Loss of over 50% over a 24 period may be tolerated in the dog.