Difference between revisions of "Masticatory Muscle Myositis"
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(Created page with "(MMM) *Occurs in dogs *Tends to affect the masseter and temporalis muscles *Autoantibodies selectively attack muscles of mastication (type IIM fibres) *Acute stage = eosinophilic...") |
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− | + | (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|monocytes]] and plasma cells | ||
+ | ***In recurrent disease plasma cells predominate | ||
+ | ***[[Muscle Necrosis|Necrotic]] myofibres, [[Muscle Atrophy|atrophy]] and attempted [[Muscle Regeneration|regeneration]] | ||
+ | **Chronic stage: | ||
+ | ***[[Muscle Atrophy|Atrophy]] predominates | ||
+ | ***Fasciculi are shrunken | ||
+ | ***Condensation of stroma -> enlarged endomysium | ||
+ | ***Focal plasma cell and lymphocyte infiltration | ||
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− | + | [[Category:Muscles - Inflammatory Pathology]] | |
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Revision as of 19:02, 3 March 2011
(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: