Difference between revisions of "Muscles Inflammatory - Pathology"

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#redirect[[:Category:Muscles - Inflammatory Pathology]]
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==Myositis==
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[[Bacterial Myositis]]
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 +
 
 +
 
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===[[Viral myositis]]===
 +
 
 +
 
 +
 
 +
===[[Parasitic Myositis]]===
 +
 
 +
 
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*Rare in domestic animals
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 +
 
 +
====Nematodes====
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*[[Trichinella|'''''Trichinella''''']] larvae
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 +
 
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*[[Ancylostomatoidea|''Ancylostoma'']] larvae
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**Cause inflammation and [[Muscle Necrosis|necrosis]]
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*[[Ascaridoidea|Ascarid]] larvae
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*[[Dirofilaria immitis|''Dirofilaria immitis'']] in dogs causing ischaemic myopathy due to [[Muscle Ischaemia|infartcs]]
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====Cestodes====
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*[[Taenia|''Taenia solium, '']] - cysticercosis in swine and humans
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*[[Taenia|''T. ovis'']] - cysticercosis in sheep
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*[[Taenia|''T. saginata'']] in cattle cysticercosis
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*[[Taenia|''Multiceps serialis'']] in rabbits, primates coenurosis
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*[[Echinococcus|''Echinococcus granulosus'']] hydatid disease in herbivores and humans
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====Protozoa====
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*'''''[[Toxoplasma gondii]]'''''
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*[[Neospora|'''''Neospora caninum''''']]
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*[[Sarcocystis|'''''Sarcocystis''''']]
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*[[Hepatozoon|'''''Hepatozoon americanum''''']]
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*'''''[[Trypanosoma]]'''''
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*'''''[[Babesia|Babesia bovis]]'''''
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====Arthropods====
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*Dipterious larvae causing [[Myiasis|myiasis]]
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*[[Hypoderma spp.|''Hypoderma'' spp.]] in cattle
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**May occasionally burrow into muscle
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[[Category:Muscles - Inflammatory Pathology]]
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===[[Immune-Mediated myositis]]===
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====Masticatory muscle myositis (MMM)====
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*Occurs in dogs
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*Tends to affect the masseter and temporalis muscles
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*Autoantibodies selectively attack muscles of mastication (type IIM fibres)
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*Acute stage = eosinophilic myositis
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**Extremely swollen, painful, hard masticatory muscles
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*Chronic stage = atrophic myositis
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**Atrophy may occur without previous acute stage
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*Grossly:
 +
**Bilateral but not necessarily symmetrical
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**At first, enlarged and oedematous muscles becominf dark red, firm with reddish streaks and yellowiss foci
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*Histologically:
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**Acute lesions:
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***Mainly eosinophilic infiltrate, few lymphocytes, [[Monocytes|monocytes]] and plasma cells
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***In recurrent disease plasma cells predominate
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***[[Muscle Necrosis|Necrotic]] myofibres, [[Muscle Atrophy|atrophy]] and attempted [[Muscle Regeneration|regeneration]]
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**Chronic stage:
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***[[Muscle Atrophy|Atrophy]] predominates
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***Fasciculi are shrunken
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***Condensation of stroma -> enlarged endomysium
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***Focal plasma cell and lymphocyte infiltration
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[[Category:Muscles - Inflammatory Pathology]]
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====[[Canine Dermatomyositis|Canine dermatomyositis]]====
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===Idiopathic myositis===
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====Canine polymyositis====
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*DOES NOT include MMM above
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*Rare
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*Clinical signs:
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**Muscle pain
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**Fever
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**Weakness, particularly in hind limbs
 +
*Grossly:
 +
**Inflammation is accompanied by muscle necrosis and regeneration
 +
*Histologically:
 +
**Inflammatory foci with lymphocytes, plasma cells and occasionally eosinophils
 +
*Possibly immunological cause
 +
*Single biopsy may not be enough to make the diagnosis as it tends to be multifocal and disseminated
 +
*Lesions similar to some infectious causes (such as ''[[Toxoplasma gondii]]'')
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 +
 
 +
[[Category:Muscles - Inflammatory Pathology]]
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 +
 
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====Canine bilateral extraocular polymyositis====
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*In Golden retrievers
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*Very rare
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*Clinical signs:
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**Acute bilateral exophthalmos
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*Involves only extraocular muscles except for retractor blbi
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*Grossly:
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**Swollen and pale extraocular muscles
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*Histologically:
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**Sterile myositis
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**Multifocal necrosis of myofibres
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**Lymphocytic, histiocytic and plasmacytic infiltrate with few [[Neutrophils|neutrophils]]
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 +
 
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 +
[[Category:Muscles - Inflammatory Pathology]]
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 +
 
 +
====Bovine and ovine eosinophilic myositis====
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*Unknown aetiology
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*Major cell involved is eosinphil
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*Usually noticed at slaughter - green muscle discoloration
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*May be caused by degenteration of [[Sarcocystis|''Sarcocystis'' spp.]]
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*Grossly:
 +
**Green discolored areas, well demarcated
 +
**Mostly in muscles of back and thighs
 +
*Histologically:
 +
**Massive eosinophil infiltration
 +
**Muscle fibres may degenerate
 +
**In old lesions - endimysial fibrosis, myofibre atrophy, some regeneration, lymphocytes, plasma cells, macrophages and few eosinophils
 +
**Capsule may form
 +
 
 +
[[Category:Muscles - Inflammatory Pathology]]
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[[Category:Musculoskeletal System - Pathology]]

Revision as of 18:59, 3 March 2011

Myositis

Bacterial Myositis


Viral myositis

Parasitic Myositis

  • Rare in domestic animals


Nematodes


Cestodes

Protozoa

Arthropods


Immune-Mediated myositis

Masticatory muscle myositis (MMM)

  • Occurs in dogs
  • Tends to affect the masseter and temporalis muscles
  • Autoantibodies selectively attack muscles of mastication (type IIM fibres)
  • Acute stage = eosinophilic myositis
    • Extremely swollen, painful, hard masticatory muscles
  • Chronic stage = atrophic myositis
    • Atrophy may occur without previous acute stage
  • Grossly:
    • Bilateral but not necessarily symmetrical
    • At first, enlarged and oedematous muscles becominf dark red, firm with reddish streaks and yellowiss foci
  • Histologically:
    • Acute lesions:
    • Chronic stage:
      • Atrophy predominates
      • Fasciculi are shrunken
      • Condensation of stroma -> enlarged endomysium
      • Focal plasma cell and lymphocyte infiltration


Canine dermatomyositis

Idiopathic myositis

Canine polymyositis

  • DOES NOT include MMM above
  • Rare
  • Clinical signs:
    • Muscle pain
    • Fever
    • Weakness, particularly in hind limbs
  • Grossly:
    • Inflammation is accompanied by muscle necrosis and regeneration
  • Histologically:
    • Inflammatory foci with lymphocytes, plasma cells and occasionally eosinophils
  • Possibly immunological cause
  • Single biopsy may not be enough to make the diagnosis as it tends to be multifocal and disseminated
  • Lesions similar to some infectious causes (such as Toxoplasma gondii)


Canine bilateral extraocular polymyositis

  • In Golden retrievers
  • Very rare
  • Clinical signs:
    • Acute bilateral exophthalmos
  • Involves only extraocular muscles except for retractor blbi
  • Grossly:
    • Swollen and pale extraocular muscles
  • Histologically:
    • Sterile myositis
    • Multifocal necrosis of myofibres
    • Lymphocytic, histiocytic and plasmacytic infiltrate with few neutrophils


Bovine and ovine eosinophilic myositis

  • Unknown aetiology
  • Major cell involved is eosinphil
  • Usually noticed at slaughter - green muscle discoloration
  • May be caused by degenteration of Sarcocystis spp.
  • Grossly:
    • Green discolored areas, well demarcated
    • Mostly in muscles of back and thighs
  • Histologically:
    • Massive eosinophil infiltration
    • Muscle fibres may degenerate
    • In old lesions - endimysial fibrosis, myofibre atrophy, some regeneration, lymphocytes, plasma cells, macrophages and few eosinophils
    • Capsule may form
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