Difference between revisions of "Muscles Inflammatory - Pathology"
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==Myositis== | ==Myositis== | ||
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| + | [[Bacterial Myositis]] | ||
*Inflammation of muscle | *Inflammation of muscle | ||
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*Occasionally my spread via the fascia | *Occasionally my spread via the fascia | ||
| + | [[Category:Muscles - Inflammatory Pathology]] | ||
====[[Black Leg]]==== | ====[[Black Leg]]==== | ||
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| − | ===Viral myositis=== | + | ===[[Viral myositis]]=== |
*Rare in the UK | *Rare in the UK | ||
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====[[Bluetongue Virus|Bluetongue]]==== | ====[[Bluetongue Virus|Bluetongue]]==== | ||
| − | ===Parasitic | + | |
| + | [[Category:Muscles - Inflammatory Pathology]] | ||
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| + | ===[[Parasitic Myositis]]=== | ||
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**May occasionally burrow into muscle | **May occasionally burrow into muscle | ||
| − | ===Immune- | + | [[Category:Muscles - Inflammatory Pathology]] |
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| + | ===[[Immune-Mediated myositis]]=== | ||
====Masticatory muscle myositis (MMM)==== | ====Masticatory muscle myositis (MMM)==== | ||
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***Condensation of stroma -> enlarged endomysium | ***Condensation of stroma -> enlarged endomysium | ||
***Focal plasma cell and lymphocyte infiltration | ***Focal plasma cell and lymphocyte infiltration | ||
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| + | [[Category:Muscles - Inflammatory Pathology]] | ||
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====[[Canine Dermatomyositis|Canine dermatomyositis]]==== | ====[[Canine Dermatomyositis|Canine dermatomyositis]]==== | ||
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*Single biopsy may not be enough to make the diagnosis as it tends to be multifocal and disseminated | *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]]'') | *Lesions similar to some infectious causes (such as ''[[Toxoplasma gondii]]'') | ||
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| + | [[Category:Muscles - Inflammatory Pathology]] | ||
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====Canine bilateral extraocular polymyositis==== | ====Canine bilateral extraocular polymyositis==== | ||
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**Multifocal necrosis of myofibres | **Multifocal necrosis of myofibres | ||
**Lymphocytic, histiocytic and plasmacytic infiltrate with few [[Neutrophils|neutrophils]] | **Lymphocytic, histiocytic and plasmacytic infiltrate with few [[Neutrophils|neutrophils]] | ||
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| + | [[Category:Muscles - Inflammatory Pathology]] | ||
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**In old lesions - endimysial fibrosis, myofibre atrophy, some regeneration, lymphocytes, plasma cells, macrophages and few eosinophils | **In old lesions - endimysial fibrosis, myofibre atrophy, some regeneration, lymphocytes, plasma cells, macrophages and few eosinophils | ||
**Capsule may form | **Capsule may form | ||
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| + | [[Category:Muscles - Inflammatory Pathology]] | ||
[[Category:Musculoskeletal System - Pathology]] | [[Category:Musculoskeletal System - Pathology]] | ||
Revision as of 18:54, 3 March 2011
Myositis
- Inflammation of muscle
Bacterial myositis
- Bacteria gain entry via:
- Direct penetration
- Blood stream
- Extension
- Lesions caused:
- Suppurative
- Serosanguinous
- Granulomatous
Abscesses
- Caused by pyogenic bacteria
- Usually:
- Arcanobacterium pyogenes in sheep and cattle
- Streptococcus equi in horses
- Corynebacterium pseudotuberculosis in sheep and goats
- Pasteurella multocida causes cellulitis in cats
- Usually localised suppuration and necrosis of myofibres
- Occasionally my spread via the fascia
Black Leg
Gas gangrene
Wooden tongue
Tuberculosis
Actinomyces bovis
Botryomycosis
Viral myositis
- Rare in the UK
Porcine encephalomyelitis
Foot and Mouth Disease
Bluetongue
Parasitic Myositis
- Rare in domestic animals
Nematodes
- Trichinella larvae
- Ancylostoma larvae
- Cause inflammation and necrosis
- Ascarid larvae
- Dirofilaria immitis in dogs causing ischaemic myopathy due to infartcs
Cestodes
- Taenia solium, - cysticercosis in swine and humans
- T. ovis - cysticercosis in sheep
- T. saginata in cattle cysticercosis
- Multiceps serialis in rabbits, primates coenurosis
- Echinococcus granulosus hydatid disease in herbivores and humans
Protozoa
Arthropods
- Dipterious larvae causing myiasis
- Hypoderma spp. in cattle
- May occasionally burrow into muscle
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:
- Mainly eosinophilic infiltrate, few lymphocytes, monocytes and plasma cells
- In recurrent disease plasma cells predominate
- Necrotic myofibres, atrophy and attempted regeneration
- Chronic stage:
- Atrophy predominates
- Fasciculi are shrunken
- Condensation of stroma -> enlarged endomysium
- Focal plasma cell and lymphocyte infiltration
- Acute lesions:
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