Difference between revisions of "Muscles Inflammatory - Pathology"

Revision as of 19:02, 3 March 2011

DOES NOT include Masticatory Muscle Myositis
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)

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

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

@@ Line 16: / Line 16: @@
-===[[Immune-Mediated myositis]]===
+===[[Immune-Mediated Myositis]]===
-====Masticatory muscle myositis (MMM)====
+====[[Masticatory Muscle Myositis]] ====
-*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
-[[Category:Muscles - Inflammatory Pathology]]
@@ Line 52: / Line 29: @@
 ====Canine polymyositis====
-*DOES NOT include MMM above
+*DOES NOT include [[Masticatory Muscle Myositis]]
 *Rare
 *Clinical signs: