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Muscles Degenerative - Pathology (view source)
Revision as of 17:31, 5 September 2008
, 17:31, 5 September 2008no edit summary
*Creatine kinase (CK) is an enzyme which leaks following injury
*Creatine kinase (CK) is an enzyme which leaks following injury
**Used to measure the extent of muscle damage
**Used to measure the extent of muscle damage
*Often is followed by [[Muscles - normal#Regeneration|regeneration]]
*Often is followed by [[Muscle Regeneration - Anatomy & Physiology|regeneration]]
*Histologically:
*Histologically:
**Hyaline hypercontracted fiber rounded at cross-section and increased diameter and eosin staining
**Hyaline hypercontracted fiber rounded at cross-section and increased diameter and eosin staining
**Histologically:
**Histologically:
***Segmental necrosis, no calcification
***Segmental necrosis, no calcification
***[[Muscles - normal#Regeneration|Regeneration]] may occur in surviving animals
***[[Muscle Regeneration - Anatomy & Physiology|Regeneration]] may occur in surviving animals
*'''Drugs'''
*'''Drugs'''
**E.g. corticosteroids, cholinesterase inhibitors, vincristine, dimethyl sulfoxide (DMSO)
**E.g. corticosteroids, cholinesterase inhibitors, vincristine, dimethyl sulfoxide (DMSO)
***Histologically:
***Histologically:
****[[Muscles Degenerative - Pathology#Necrosis|Segmental necrosis]]
****[[Muscles Degenerative - Pathology#Necrosis|Segmental necrosis]]
****Possibly [[Muscles - normal#Regeneration|regeneration]] in surviving animals
****Possibly [[Muscle Regeneration - Anatomy & Physiology|regeneration]] in surviving animals
***Can cause rapid onset recumbency and potentially death
***Can cause rapid onset recumbency and potentially death
***Usually due to mixing errors in feed
***Usually due to mixing errors in feed
**Also from intramuscular injections, e.g. oxytetracycline, lidocaine, chloramphenicol, produce local necrosis
**Also from intramuscular injections, e.g. oxytetracycline, lidocaine, chloramphenicol, produce local necrosis
***As [[Muscles - normal|satellite cells]] are destroyes, repair is via fibrosis with some [[Muscles - normal#Regeneration|budding]]
***As satellite cells are destroyes, repair is via fibrosis with some budding
*'''Chemicals'''
*'''Chemicals'''
**Iron injections can cause local myonecrosis
**Iron injections can cause local myonecrosis
**Pigs also have lesions in their [[Myocardial - Pathology#Hyaline degeneration|heart]] and [[Liver General Pathology - Pathology#Hepatosis dietica|liver]]
**Pigs also have lesions in their [[Myocardial - Pathology#Hyaline degeneration|heart]] and [[Liver General Pathology - Pathology#Hepatosis dietica|liver]]
*Histologically:
*Histologically:
**[[Muscles Degenerative - Pathology#Necrosis|Segmental necrosis]] +/- [[Muscles Degenerative - Pathology#Calcification|calcification]] and [[Muscles - normal#Regeneration|regeneration]]
**[[Muscles Degenerative - Pathology#Necrosis|Segmental necrosis]] +/- [[Muscles Degenerative - Pathology#Calcification|calcification]] and [[Muscle Regeneration - Anatomy & Physiology|regeneration]]
**Multifocal and multiphasic lesions
**Multifocal and multiphasic lesions
*Firstly [[Muscles Degenerative - Pathology#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 [[Muscle Regeneration - Anatomy & Physiology|regeneration]] but myoblast precursors have to be recruited from viable fibres
*-> death of all cells
*-> death of all cells
*Mostly healed by fibrosis and scar formation
*Mostly healed by fibrosis and scar formation
*May attempt regeneration by [[Muscles - normal#Regeneration|budding]]
*May attempt regeneration by [[Muscle Regeneration - Anatomy & Physiology|budding]]
Main causes:
Main causes:
*'''Vascular occlusion'''
*'''Vascular occlusion'''
**Complete rupture - ''e.g.'' quadriceps of racing greyhounds
**Complete rupture - ''e.g.'' quadriceps of racing greyhounds
**Myorrhexis (tearing) - ''e.g.'' slippery floor causing 'splits' in cattle -> adductor muscle tear
**Myorrhexis (tearing) - ''e.g.'' slippery floor causing 'splits' in cattle -> adductor muscle tear
*Healing is by [[Muscles - normal#Regeneration|regeneration]]
*Healing is by [[Muscle Regeneration - Anatomy & Physiology|regeneration]]
*Fibrosis (scarring) will compromise function
*Fibrosis (scarring) will compromise function
*During [[Bones Fractures - Pathology|fractures]], fragments may cause further trauma if moved
*During [[Bones Fractures - Pathology|fractures]], fragments may cause further trauma if moved