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Created page with "==Generalised (Systemic) Venous Congestion== * Usually associated with increased in circulation time due to cardiac pumping inefficiency. ** The cardiac inefficiency is usually..."
==Generalised (Systemic) Venous Congestion==
* Usually associated with increased in circulation time due to cardiac pumping inefficiency.
** The cardiac inefficiency is usually the result of:
**# Cardiac disease, e.g.
**#* Valvular disease
**#* Myocardial degeneration
**#* Cardiac malformation
**# Increased pulmonary vascular resistance
**#* Due to fibrosis or emphysema.
** Reduced cardiac output gives an increased circulation time and a larger venous volume.
** The relative quantity of deoxygenated blood in tissues rises.
* Some organs are more susceptible to venous congestion than others.
** Lungs
** [[Liver - Anatomy & Physiology|Liver]]
** [[Spleen - Anatomy & Physiology|Spleen]]
** Kidneys (to a lesser extent)).
===Pathology===
* Severe congestion results in increased size and weight of organs.
** Ultimately, [[Oedema - Pathology|oedema]] occurs.
* Encapsulated organs (e.g. [[Spleen - Anatomy & Physiology|spleen]], [[Liver - Anatomy & Physiology|liver]]):
** Become swollen.
*** Turgid on palpation.
*** Have rounded free borders.
** Are frequently darker red or purple.
** Ooze dark (deoxygenated) blood on cut surface.
* [[Oedema - Pathology#Composition of Oedema Fluid|Oedema fluid]] may be seen (e.g. lung) if the condition is prolonged.
** E.g. in the lung.
* Accumulation of deoxygenated blood often results in cyanosis of tissues.
* Where the condition persists, hypoxia induces degenerative changes and fibrosis.
** Replacement of degenerate tissue by more compact fibrous tissue often leads to irregular surface depressions known as induration.
* Where changes are more insidious, cellular and organoid atrophy may occur with diminution in size.
===Sequelae===
* Severe congestion can induce:
** [[Oedema - Pathology|'''Oedema''']] '''formation'''
*** E.g. in the lung, associated with cardiac mitral valvular disease.
** '''Stagnation hypoxia and capillary damage '''
** Minor capillary [[Haemorrhage - Pathology|haemorrhage]] is induced by hypoxia.
*** Is often followed by [[Pigmentation and Calcification - Pathology#Haemosiderin|haemosiderin]] deposition.
** '''[[Degenerations and Infiltrations - Pathology#Cellular Fatty Change|Fatty change]]'''
*** Degenerative change, characterised by [[Degenerations and Infiltrations - Pathology#Cellular Fatty Change|fatty change]], occurs when whole parenchymatous organs are affected.
**** E.g. the [[Liver - Anatomy & Physiology|liver]] and kidneys.
==Localised Venous Congestion==
* Affects individual organs or tissues.
* May be
** Acute
*** E.g. due to sudden blockage of drainage.
** More chronic.
*** A slower but progressive blockage to venous drainage.
*** May result in tissue atrophy.
===Causes===
# '''Extra-vascular pressure''', for example
#* Ligatures or bandages.
#* Adjacent masses
#** [[Neoplasia - Pathology|Tumours]]
#** [[Purulent Inflammation|Abscesses]]
#** [[Granulomatous Inflammation|Granulomas]]
#* Organ displacements or torsions.
# '''Intra-vascular obstruction'''
#* [[Thrombosis|Thrombosis]] or [[Embolism|embolism]].
# '''Vasculitis'''
#* Inflammation in and around the vessel wall (phlebitis).
#* May be iatrogenic.
===Gross===
* The affected organs or tissues show similar changes to venous congestion of systemic origin.
** Here, the changes are confined to one organ or tissue area.
* Organ displacements, e.g. [[Intussusception|intussusception]], often show venous congestion followed by hypoxic degeneration and sloughing of tissue.
===Histological===
* Affected tissues are seen to be congested .
** Red blood cell stasis in venules and capillaries.
* Degeneration of tissue cells in the area affected.
** Varying numbers of inflammatory cells around these degenerate foci.
*** [[Oedema - Pathology|Oedema]] and leaked plasma protein deposits.
===Sequelae===
* Sequelae depend on:
** Severity
** Speed of onset of hypoxia
** Presence of alternative routes of venous drainage.
* The usual effect is hypoxic localised degeneration.
* Insidious, long-standing congestion tends to result in a combination of fibrosis and atrophy.
==Hypostatic Congestion==
* Seen in long-term recumbent, chronically ill animals, or those dying slowly.
* The term refers to congestion of the dependant parts of an organ in a failing circulation.
** In cases of paired organs, it applies to the dependant organ .
* Particularly affects the lungs and kidneys.
[[Category:Circulatory Disorders - Pathology]]
* Usually associated with increased in circulation time due to cardiac pumping inefficiency.
** The cardiac inefficiency is usually the result of:
**# Cardiac disease, e.g.
**#* Valvular disease
**#* Myocardial degeneration
**#* Cardiac malformation
**# Increased pulmonary vascular resistance
**#* Due to fibrosis or emphysema.
** Reduced cardiac output gives an increased circulation time and a larger venous volume.
** The relative quantity of deoxygenated blood in tissues rises.
* Some organs are more susceptible to venous congestion than others.
** Lungs
** [[Liver - Anatomy & Physiology|Liver]]
** [[Spleen - Anatomy & Physiology|Spleen]]
** Kidneys (to a lesser extent)).
===Pathology===
* Severe congestion results in increased size and weight of organs.
** Ultimately, [[Oedema - Pathology|oedema]] occurs.
* Encapsulated organs (e.g. [[Spleen - Anatomy & Physiology|spleen]], [[Liver - Anatomy & Physiology|liver]]):
** Become swollen.
*** Turgid on palpation.
*** Have rounded free borders.
** Are frequently darker red or purple.
** Ooze dark (deoxygenated) blood on cut surface.
* [[Oedema - Pathology#Composition of Oedema Fluid|Oedema fluid]] may be seen (e.g. lung) if the condition is prolonged.
** E.g. in the lung.
* Accumulation of deoxygenated blood often results in cyanosis of tissues.
* Where the condition persists, hypoxia induces degenerative changes and fibrosis.
** Replacement of degenerate tissue by more compact fibrous tissue often leads to irregular surface depressions known as induration.
* Where changes are more insidious, cellular and organoid atrophy may occur with diminution in size.
===Sequelae===
* Severe congestion can induce:
** [[Oedema - Pathology|'''Oedema''']] '''formation'''
*** E.g. in the lung, associated with cardiac mitral valvular disease.
** '''Stagnation hypoxia and capillary damage '''
** Minor capillary [[Haemorrhage - Pathology|haemorrhage]] is induced by hypoxia.
*** Is often followed by [[Pigmentation and Calcification - Pathology#Haemosiderin|haemosiderin]] deposition.
** '''[[Degenerations and Infiltrations - Pathology#Cellular Fatty Change|Fatty change]]'''
*** Degenerative change, characterised by [[Degenerations and Infiltrations - Pathology#Cellular Fatty Change|fatty change]], occurs when whole parenchymatous organs are affected.
**** E.g. the [[Liver - Anatomy & Physiology|liver]] and kidneys.
==Localised Venous Congestion==
* Affects individual organs or tissues.
* May be
** Acute
*** E.g. due to sudden blockage of drainage.
** More chronic.
*** A slower but progressive blockage to venous drainage.
*** May result in tissue atrophy.
===Causes===
# '''Extra-vascular pressure''', for example
#* Ligatures or bandages.
#* Adjacent masses
#** [[Neoplasia - Pathology|Tumours]]
#** [[Purulent Inflammation|Abscesses]]
#** [[Granulomatous Inflammation|Granulomas]]
#* Organ displacements or torsions.
# '''Intra-vascular obstruction'''
#* [[Thrombosis|Thrombosis]] or [[Embolism|embolism]].
# '''Vasculitis'''
#* Inflammation in and around the vessel wall (phlebitis).
#* May be iatrogenic.
===Gross===
* The affected organs or tissues show similar changes to venous congestion of systemic origin.
** Here, the changes are confined to one organ or tissue area.
* Organ displacements, e.g. [[Intussusception|intussusception]], often show venous congestion followed by hypoxic degeneration and sloughing of tissue.
===Histological===
* Affected tissues are seen to be congested .
** Red blood cell stasis in venules and capillaries.
* Degeneration of tissue cells in the area affected.
** Varying numbers of inflammatory cells around these degenerate foci.
*** [[Oedema - Pathology|Oedema]] and leaked plasma protein deposits.
===Sequelae===
* Sequelae depend on:
** Severity
** Speed of onset of hypoxia
** Presence of alternative routes of venous drainage.
* The usual effect is hypoxic localised degeneration.
* Insidious, long-standing congestion tends to result in a combination of fibrosis and atrophy.
==Hypostatic Congestion==
* Seen in long-term recumbent, chronically ill animals, or those dying slowly.
* The term refers to congestion of the dependant parts of an organ in a failing circulation.
** In cases of paired organs, it applies to the dependant organ .
* Particularly affects the lungs and kidneys.
[[Category:Circulatory Disorders - Pathology]]