Difference between revisions of "Muscles Inflammatory - Pathology"
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− | # | + | {{review}} |
+ | |||
+ | {{toplink | ||
+ | |backcolour =CDE472 | ||
+ | |linkpage =Musculoskeletal System - Pathology | ||
+ | |linktext =Musculoskeletal System | ||
+ | |maplink = Musculoskeletal System (Content Map) - Pathology | ||
+ | |pagetype =Pathology | ||
+ | |sublink1=Muscles - Pathology | ||
+ | |subtext1=MUSCLES | ||
+ | }} | ||
+ | <br> | ||
+ | ==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: | ||
+ | **[[Arcanobacter pyogenes|''Arcanobacterium pyogenes'']] in sheep and cattle | ||
+ | **[[Respiratory Bacterial Infections - Pathology#Strangles|''Streptococcus equi'']] in horses | ||
+ | **''[[Corynebacterium pseudotuberculosis]]'' in sheep and goats | ||
+ | **[[Pasteurella multocida|''Pasteurella multocida'']] causes cellulitis in cats | ||
+ | *Usually localised suppuration and necrosis of myofibres | ||
+ | *Occasionally my spread via the fascia | ||
+ | |||
+ | |||
+ | ====[[Black Leg]]==== | ||
+ | |||
+ | ====[[Gas Gangrene|Gas gangrene]]==== | ||
+ | |||
+ | ====[[Actinobacillosis|Wooden tongue]]==== | ||
+ | |||
+ | ====[[Tuberculosis]]==== | ||
+ | |||
+ | ====''[[Actinomyces bovis]]''==== | ||
+ | *"[[Lumpy jaw]]" | ||
+ | |||
+ | ====[[Botryomycosis]]==== | ||
+ | |||
+ | |||
+ | |||
+ | |||
+ | ===Viral myositis=== | ||
+ | |||
+ | *Rare in the UK | ||
+ | |||
+ | ====[[Porcine encephalomyelitis]]==== | ||
+ | |||
+ | ====[[Foot and Mouth Disease]]==== | ||
+ | |||
+ | |||
+ | ====[[Bluetongue Virus|Bluetongue]]==== | ||
+ | |||
+ | ===Parasitic myositis=== | ||
+ | |||
+ | |||
+ | *Rare in domestic animals | ||
+ | |||
+ | |||
+ | ====Nematodes==== | ||
+ | |||
+ | *[[Trichinella|'''''Trichinella''''']] larvae | ||
+ | |||
+ | |||
+ | *[[Ancylostomatoidea|''Ancylostoma'']] larvae | ||
+ | **Cause inflammation and [[Muscles Degenerative - Pathology#Necrosis|necrosis]] | ||
+ | *[[Ascaridoidea|Ascarid]] larvae | ||
+ | *[[Dirofilaria immitis|''Dirofilaria immitis'']] in dogs causing ischaemic myopathy due to [[Muscles Degenerative - Pathology#Ischaemia|infartcs]] | ||
+ | |||
+ | ====Cestodes==== | ||
+ | |||
+ | *[[Taenia|''Taenia solium, '']] - cysticercosis in swine and humans | ||
+ | *[[Taenia|''T. ovis'']] - cysticercosis in sheep | ||
+ | *[[Taenia|''T. saginata'']] in cattle cysticercosis | ||
+ | *[[Taenia|''Multiceps serialis'']] in rabbits, primates coenurosis | ||
+ | *[[Echinococcus|''Echinococcus granulosus'']] hydatid disease in herbivores and humans | ||
+ | |||
+ | ====Protozoa==== | ||
+ | |||
+ | *'''''[[Toxoplasma gondii]]''''' | ||
+ | |||
+ | *[[Neospora|'''''Neospora caninum''''']] | ||
+ | |||
+ | *[[Sarcocystis|'''''Sarcocystis''''']] | ||
+ | |||
+ | *[[Hepatozoon|'''''Hepatozoon americanum''''']] | ||
+ | |||
+ | *'''''[[Trypanosoma]]''''' | ||
+ | |||
+ | *'''''[[Babesia|Babesia bovis]]''''' | ||
+ | |||
+ | ====Arthropods==== | ||
+ | |||
+ | *Dipterious larvae causing [[Myiasis|myiasis]] | ||
+ | *[[Hypoderma spp.|''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|monocytes]] and plasma cells | ||
+ | ***In recurrent disease plasma cells predominate | ||
+ | ***[[Muscles Degenerative - Pathology#Necrosis|Necrotic]] myofibres, [[Muscles Degenerative - Pathology#Atrophy|atrophy]] and attempted [[Muscle Regeneration - Anatomy & Physiology|regeneration]] | ||
+ | **Chronic stage: | ||
+ | ***[[Muscles Degenerative - Pathology#Atrophy|Atrophy]] predominates | ||
+ | ***Fasciculi are shrunken | ||
+ | ***Condensation of stroma -> enlarged endomysium | ||
+ | ***Focal plasma cell and lymphocyte infiltration | ||
+ | |||
+ | ====[[Muscles Developmental - Pathology#Canine dermatomyositis|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|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|''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 |
Revision as of 11:13, 17 October 2010
This article has been peer reviewed but is awaiting expert review. If you would like to help with this, please see more information about expert reviewing. |
|
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