Difference between revisions of "Muscles Developmental - Pathology"

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#REDIRECT[[:Category:Muscles - Developmental Pathology]]
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{{review}}
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{{toplink
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|backcolour =CDE472
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|linkpage =Musculoskeletal System - Pathology
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|linktext =Musculoskeletal System
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|maplink = Musculoskeletal System (Content Map) - Pathology
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|pagetype =Pathology
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|sublink1=Muscles - Pathology
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|subtext1=MUSCLES
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}}
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<br>
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===Congenital diaphragmatic defects===
 +
 
 +
*Clefts may lead to [[Peritoneal Cavity Developmental - Pathology#Pleuroperitoneal diaphragmatic hernia|herniation]] of abdominal organs into thoracic cavity in any species
 +
 
 +
 
 +
===Myofibrillar hypoplasia===
 +
 
 +
*In piglets
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* = '''Splayleg'''
 +
*May spontaneously resolve
 +
*Unknown cause
 +
*Responsible for significant deaths
 +
 
 +
 
 +
===Hyperplasia of muscle fibres===
 +
 
 +
*In calves and lambs
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*'''“Double muscling”'''
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**Increased number of myofibres in affected muscle (thighs, rump, loin)
 +
**Predisposes to dystocia
 +
 
 +
 
 +
===Muscular dystrophies===
 +
 
 +
*Inherited group of degenerative muscular diseases
 +
*Progressive muscle weakness and wasting
 +
*Usually due to a genetic fault -> muscular protein deficiency
 +
**Duchenne MD in humans due to dystrophin deficiency also present in some animals
 +
**Dystrophin gene mutations reported in the Golden Retriever, Rottweiler, German shorthaired pointer and Irish terrier ''etc.''
 +
*Inadequate [[Muscle Regeneration - Anatomy & Physiology|regeneration]], [[Muscles Hyperplastic and Neoplastic - Pathology#Hypertrophy|compensatory hypertrophy]]
 +
*More about [[Muscular dystrophy]]
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 +
 
 +
===Glycogen storage diseases===
 +
 
 +
*Caused by a deficiency of an enzyme
 +
*See [[Degenerations and Infiltrations - Pathology#Glycogen infiltration|general pathology]]
 +
*Type II glycogenosis
 +
**Deficiency of acid maltase
 +
**In Shorthorn cattle
 +
**Muscular weakness and incoordination
 +
**Glycogen stored in skeletal muscle, heart and CNS
 +
**Type I and II muscle fibres contain glycogen vacuoles
 +
*Type III glycogenosis
 +
**Deficiency of debranching enzyme
 +
**In dogs
 +
**Causes [[Myocardial - Pathology#Hypertrophic cardiomyopathy|hypertrophic cardiomyopathy]] and hepatomegaly
 +
**Glycogen in skeletal and cardiac muscle, neurons nad hepatocytes
 +
 
 +
 
 +
===Steatosis===
 +
 
 +
*Also called '''lipomatosis'''
 +
*In cattle, sheep and pigs
 +
*Fat replaces lost muscle fibres
 +
*Pale muscle, bilaterally symmetrical
 +
*No clinical significance
 +
*Noticed at slaughter or necropsy
 +
 
 +
 
 +
===Myasthenia gravis (MG)===
 +
 
 +
*'''Acquired'''
 +
**Autoimmune disease
 +
***Antibodies directed against acetyl choline receptors
 +
**Associated with [[Thymus - Pathology|thymomas]], [[Megaoesophagus|megaoesophagus]] and dysphagia
 +
**In adult dogs
 +
*'''Congenital'''
 +
**Inherited deficiency in acetyl choline receptors
 +
**Rare
 +
**Newfoundland, Jack Russel Terrier, Springer Spaniels – genetic predisposition
 +
**In dogs – 4 DLA genes recognized: DLA-12, DLA-88, DLA-79 and DLA-64
 +
**Associated with HLA gene in humans
 +
**No antibodies against acetyl choline receptors in serum
 +
**Non-specific muscle [[Muscles Degenerative - Pathology#Atrophy|disuse atrophy]] and fibrosis or no changes on histology
 +
*Both forms manifest as weakness which worsens on exercise
 +
 
 +
===Canine dermatomyositis===
 +
 
 +
*Hereditary in Collies and Shetland sheepdgs
 +
*Lesions resemble [[Muscles Inflammatory - Pathology#Canine polymyositis|canine polymyositis]]
 +
*Also degeneration of blood vessels -> muscle [[Muscles Degenerative - Pathology#Ischaemia|microinfarcts]]
 +
*Usually generalised but temporalis and other masticatory muscles may be involved the most
 +
*Microscopically: inclusion bodies in endothelial cells
 +
*Best place for biopsy is anterior and most superficial temporalis muscle
 +
*Also involves [[Skin Immunologic - Pathology#Dermatomyositis|skin]], may involve the oesophagus
 +
 
 +
===[[Muscles Degenerative - Pathology#Porcine stress syndrome|Porcine stress syndrome]]===

Revision as of 13:02, 28 May 2010

 This article has been peer reviewed but is awaiting expert review. If you would like to help with this, please see more information about expert reviewing.


WikiPathWikiPath Banner.png
()Map MUSCULOSKELETAL SYSTEM (Map)
MUSCLES



Congenital diaphragmatic defects

  • Clefts may lead to herniation of abdominal organs into thoracic cavity in any species


Myofibrillar hypoplasia

  • In piglets
  • = Splayleg
  • May spontaneously resolve
  • Unknown cause
  • Responsible for significant deaths


Hyperplasia of muscle fibres

  • In calves and lambs
  • “Double muscling”
    • Increased number of myofibres in affected muscle (thighs, rump, loin)
    • Predisposes to dystocia


Muscular dystrophies

  • Inherited group of degenerative muscular diseases
  • Progressive muscle weakness and wasting
  • Usually due to a genetic fault -> muscular protein deficiency
    • Duchenne MD in humans due to dystrophin deficiency also present in some animals
    • Dystrophin gene mutations reported in the Golden Retriever, Rottweiler, German shorthaired pointer and Irish terrier etc.
  • Inadequate regeneration, compensatory hypertrophy
  • More about Muscular dystrophy


Glycogen storage diseases

  • Caused by a deficiency of an enzyme
  • See general pathology
  • Type II glycogenosis
    • Deficiency of acid maltase
    • In Shorthorn cattle
    • Muscular weakness and incoordination
    • Glycogen stored in skeletal muscle, heart and CNS
    • Type I and II muscle fibres contain glycogen vacuoles
  • Type III glycogenosis
    • Deficiency of debranching enzyme
    • In dogs
    • Causes hypertrophic cardiomyopathy and hepatomegaly
    • Glycogen in skeletal and cardiac muscle, neurons nad hepatocytes


Steatosis

  • Also called lipomatosis
  • In cattle, sheep and pigs
  • Fat replaces lost muscle fibres
  • Pale muscle, bilaterally symmetrical
  • No clinical significance
  • Noticed at slaughter or necropsy


Myasthenia gravis (MG)

  • Acquired
    • Autoimmune disease
      • Antibodies directed against acetyl choline receptors
    • Associated with thymomas, megaoesophagus and dysphagia
    • In adult dogs
  • Congenital
    • Inherited deficiency in acetyl choline receptors
    • Rare
    • Newfoundland, Jack Russel Terrier, Springer Spaniels – genetic predisposition
    • In dogs – 4 DLA genes recognized: DLA-12, DLA-88, DLA-79 and DLA-64
    • Associated with HLA gene in humans
    • No antibodies against acetyl choline receptors in serum
    • Non-specific muscle disuse atrophy and fibrosis or no changes on histology
  • Both forms manifest as weakness which worsens on exercise

Canine dermatomyositis

  • Hereditary in Collies and Shetland sheepdgs
  • Lesions resemble canine polymyositis
  • Also degeneration of blood vessels -> muscle microinfarcts
  • Usually generalised but temporalis and other masticatory muscles may be involved the most
  • Microscopically: inclusion bodies in endothelial cells
  • Best place for biopsy is anterior and most superficial temporalis muscle
  • Also involves skin, may involve the oesophagus

Porcine stress syndrome

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