Difference between revisions of "Masticatory Muscle Myositis"
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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 | |
| − | *Mainly eosinophilic infiltrate, few lymphocytes, [[Monocytes|monocytes]] and plasma cells | + | **At first, enlarged and oedematous muscles becominf dark red, firm with reddish streaks and yellowiss foci |
| − | *In recurrent disease plasma cells predominate | + | *Histologically: |
| − | *[[Muscle Necrosis|Necrotic]] myofibres, [[Muscle Atrophy|atrophy]] and attempted [[Muscle Regeneration|regeneration]] | + | **Acute lesions: |
| − | + | ***Mainly eosinophilic infiltrate, few lymphocytes, [[Monocytes|monocytes]] and plasma cells | |
| − | + | ***In recurrent disease plasma cells predominate | |
| − | *[[Muscle Atrophy|Atrophy]] predominates | + | ***[[Muscle Necrosis|Necrotic]] myofibres, [[Muscle Atrophy|atrophy]] and attempted [[Muscle Regeneration|regeneration]] |
| − | *Fasciculi are shrunken | + | **Chronic stage: |
| − | *Condensation of stroma | + | ***[[Muscle Atrophy|Atrophy]] predominates |
| − | *Focal plasma cell and lymphocyte infiltration | + | ***Fasciculi are shrunken |
| + | ***Condensation of stroma -> enlarged endomysium | ||
| + | ***Focal plasma cell and lymphocyte infiltration | ||
[[Category:Immune-Mediated Myositis]] | [[Category:Immune-Mediated Myositis]] | ||
| − | |||
| − | |||
Revision as of 22:56, 5 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: