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| − | ===[[Immune-Mediated myositis]]=== | + | ===[[Immune-Mediated Myositis]]=== |
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| − | ====Masticatory muscle myositis (MMM)==== | + | ====[[Masticatory Muscle Myositis]] ==== |
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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:
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| − | **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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| − |
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| − | [[Category:Muscles - Inflammatory Pathology]]
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| | ====Canine polymyositis==== | | ====Canine polymyositis==== |
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| − | *DOES NOT include MMM above | + | *DOES NOT include [[Masticatory Muscle Myositis]] |
| | *Rare | | *Rare |
| | *Clinical signs: | | *Clinical signs: |