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| *Cloudy swelling, hydropic, vacuolar, granular and fatty change | | *Cloudy swelling, hydropic, vacuolar, granular and fatty change |
| *Occur following many different types of insult and are usually '''segmental''' | | *Occur following many different types of insult and are usually '''segmental''' |
− | *If regeneration does not occur after formation of small vacuoles, [[Muscles - degenerative#Necrosis|necrosis]] follows | + | *If regeneration does not occur after formation of small vacuoles, [[Muscles Degenerative - Pathology#Necrosis|necrosis]] follows |
| **Vacuolation -> floccular degeneration -> granular degeneration -> [[General Pathology - Degenerations and Infiltrations#Hyaline Degeneration|hyaline]] and [[Zenker degeneration|Zenker’s degeneration]] | | **Vacuolation -> floccular degeneration -> granular degeneration -> [[General Pathology - Degenerations and Infiltrations#Hyaline Degeneration|hyaline]] and [[Zenker degeneration|Zenker’s degeneration]] |
| *[[General Pathology - Degenerations and Infiltrations#Vacuolar Degeneration|'''Vacuolar degeneration''']]: | | *[[General Pathology - Degenerations and Infiltrations#Vacuolar Degeneration|'''Vacuolar degeneration''']]: |
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| ***Bundles of dense fibrous connective tissue | | ***Bundles of dense fibrous connective tissue |
| ***May contain accumulations of cartilage, bone or calcium | | ***May contain accumulations of cartilage, bone or calcium |
− | **Hyperplastic connective tissue -> compression of adjacent skeletal muscle -> [[Muscles - degenerative#Atrophy|atrophy]] | + | **Hyperplastic connective tissue -> compression of adjacent skeletal muscle -> [[Muscles Degenerative - Pathology#Atrophy|atrophy]] |
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| **Normal portion of fibre may detach from necrotic part -> retraction caps | | **Normal portion of fibre may detach from necrotic part -> retraction caps |
| **Infarction may cause '''discoid degeneration''' - necrotic fibres detach at '''Z lines''' | | **Infarction may cause '''discoid degeneration''' - necrotic fibres detach at '''Z lines''' |
− | **May [[Muscles - degenerative#Calcification|mineralise]] | + | **May [[Muscles Degenerative - Pathology#Calcification|mineralise]] |
| *[[Zenker degeneration|'''Zenker's degeneration''']] - secondary to systemic disease | | *[[Zenker degeneration|'''Zenker's degeneration''']] - secondary to systemic disease |
| **Scattered small segments of necrosis and fast regeneration | | **Scattered small segments of necrosis and fast regeneration |
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| **Grossly: | | **Grossly: |
| ***Pale areas with ill-defined borders | | ***Pale areas with ill-defined borders |
− | ***May involve very extensive [[Muscles - degenerative#Necrosis|necrosis]] | + | ***May involve very extensive [[Muscles Degenerative - Pathology#Necrosis|necrosis]] |
| **Histologically: | | **Histologically: |
| ***Segmental necrosis, no calcification | | ***Segmental necrosis, no calcification |
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| ****Pale streaks, mostly in hind limbs | | ****Pale streaks, mostly in hind limbs |
| ***Histologically: | | ***Histologically: |
− | ****[[Muscles - degenerative#Necrosis|Segmental necrosis]] | + | ****[[Muscles Degenerative - Pathology#Necrosis|Segmental necrosis]] |
| ****Possibly [[Muscles - normal#Regeneration|regeneration]] in surviving animals | | ****Possibly [[Muscles - normal#Regeneration|regeneration]] in surviving animals |
| ***Can cause rapid onset recumbency and potentially death | | ***Can cause rapid onset recumbency and potentially death |
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| *'''Mycotoxins''' | | *'''Mycotoxins''' |
| **Metabolites cause persistent tremors | | **Metabolites cause persistent tremors |
− | **Lesions in skeletal muscle only, possibly secondary to sustained contractions (similar to [[Muscles - degenerative#Exertional myopathies|exertional myopathy]]) | + | **Lesions in skeletal muscle only, possibly secondary to sustained contractions (similar to [[Muscles Degenerative - Pathology#Exertional myopathies|exertional myopathy]]) |
| **Histologically: | | **Histologically: |
− | ***Tiny foci of [[Muscles - degenerative#Necrosis|segmental necrosis]] | + | ***Tiny foci of [[Muscles Degenerative - Pathology#Necrosis|segmental necrosis]] |
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| *[[Adrenal Glands - Pathology#Adrenal Hyperfunction|Hyperadrenocorticism]] | | *[[Adrenal Glands - Pathology#Adrenal Hyperfunction|Hyperadrenocorticism]] |
| **Muscle weakness is a clinical sign | | **Muscle weakness is a clinical sign |
− | **-> [[Muscles - degenerative#Atrophy|muscle atrophy]] | + | **-> [[Muscles Degenerative - Pathology#Atrophy|muscle atrophy]] |
| ***Type II myofibre atrophy is non-specific | | ***Type II myofibre atrophy is non-specific |
| ***Type IIB myofibre atrophy is preferential in hyperadrenocorticism | | ***Type IIB myofibre atrophy is preferential in hyperadrenocorticism |
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| **Vitamin E usually mops up OFRs | | **Vitamin E usually mops up OFRs |
| **Selenium as part of glutathione peroxidase neutralises effects of OFRs | | **Selenium as part of glutathione peroxidase neutralises effects of OFRs |
− | **If Vit E or Se are deficient -> the balance shifts to membrane damage, calcium entry and mitochondrial damage -> cell swells and dies -> segmental muscle [[Muscles - degenerative#Necrosis|necrosis]] | + | **If Vit E or Se are deficient -> the balance shifts to membrane damage, calcium entry and mitochondrial damage -> cell swells and dies -> segmental muscle [[Muscles Degenerative - Pathology#Necrosis|necrosis]] |
| *Grossly: | | *Grossly: |
| **Lesions are bilaterally symmetrical in hard working muscles (vary with species) | | **Lesions are bilaterally symmetrical in hard working muscles (vary with species) |
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| **Pigs also have lesions in their [[Myocardial - Pathology#Hyaline degeneration|heart]] and [[Liver - general pathology#Hepatosis dietica|liver]] | | **Pigs also have lesions in their [[Myocardial - Pathology#Hyaline degeneration|heart]] and [[Liver - general pathology#Hepatosis dietica|liver]] |
| *Histologically: | | *Histologically: |
− | **[[Muscles - degenerative#Necrosis|Segmental necrosis]] +/- [[Muscles - degenerative#Calcification|calcification]] and [[Muscles - normal#Regeneration|regeneration]] | + | **[[Muscles Degenerative - Pathology#Necrosis|Segmental necrosis]] +/- [[Muscles Degenerative - Pathology#Calcification|calcification]] and [[Muscles - normal#Regeneration|regeneration]] |
| **Multifocal and multiphasic lesions | | **Multifocal and multiphasic lesions |
| | | |
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| ***Salmon pink muscles -> dark, moist, swollen +/- pale streaks | | ***Salmon pink muscles -> dark, moist, swollen +/- pale streaks |
| **Histologically: | | **Histologically: |
− | ***Segmental myofibre [[Muscles - degenerative#Necrosis|necrosis]] | + | ***Segmental myofibre [[Muscles Degenerative - Pathology#Necrosis|necrosis]] |
| ****Multifocal and monophasic, but may be multiphasic if repeated bouts | | ****Multifocal and monophasic, but may be multiphasic if repeated bouts |
| ***Both, type IIA and IIB fibres affected; type IIB preferentially affected in acute disease | | ***Both, type IIA and IIB fibres affected; type IIB preferentially affected in acute disease |
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| *Histologically: | | *Histologically: |
| **Segmental hypercontraction | | **Segmental hypercontraction |
− | **Monophasic, multifocal [[Muscles - degenerative#Necrosis|segmental necrosis]] | + | **Monophasic, multifocal [[Muscles Degenerative - Pathology#Necrosis|segmental necrosis]] |
| *Inherited | | *Inherited |
| *Triggered by halothane anaesthesia, stress of handling, transportation or slaughter | | *Triggered by halothane anaesthesia, stress of handling, transportation or slaughter |
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| ===Ischaemia=== | | ===Ischaemia=== |
| | | |
− | *Firstly [[Muscles - degenerative#Necrosis|segmental necrosis]] | + | *Firstly [[Muscles Degenerative - Pathology#Necrosis|segmental necrosis]] |
| *-> death of satellite cells | | *-> death of satellite cells |
| **Causes [[Muscles - normal#Regeneration|regeneration]] but myoblast precursors have to be recruited from viable fibres | | **Causes [[Muscles - normal#Regeneration|regeneration]] but myoblast precursors have to be recruited from viable fibres |
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| **Infarction from embolism is rare due to collateral circulation | | **Infarction from embolism is rare due to collateral circulation |
| **Extension of infarcts depends on size of vessels occluded | | **Extension of infarcts depends on size of vessels occluded |
− | ***Small capillaries -> segmental [[Muscles - degenerative#Necrosis|necrosis]] | + | ***Small capillaries -> segmental [[Muscles Degenerative - Pathology#Necrosis|necrosis]] |
| ***Large arteries -> whole muscle areas, including sattelite cells, are killed | | ***Large arteries -> whole muscle areas, including sattelite cells, are killed |
| **Healed by fibrosis | | **Healed by fibrosis |
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| **Compression of myofibres | | **Compression of myofibres |
| **Secondary from haemorrhage (bruising) | | **Secondary from haemorrhage (bruising) |
− | ***May increase muscle pressure -> [[Muscles - degenerative#Ischaemia|ischaemia]] -> [[Muscles - degenerative#Necrosis|necrosis]] | + | ***May increase muscle pressure -> [[Muscles Degenerative - Pathology#Ischaemia|ischaemia]] -> [[Muscles Degenerative - Pathology#Necrosis|necrosis]] |
| **Partial rupture - ''e.g.'' of diaphragm in road traffic accident | | **Partial rupture - ''e.g.'' of diaphragm in road traffic accident |
| **Complete rupture - ''e.g.'' quadriceps of racing greyhounds | | **Complete rupture - ''e.g.'' quadriceps of racing greyhounds |