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| − | ==Arthritis== | + | == |
| − | [[Image:Cattle fibrinopurulent arthritis.jpg|right|thumb|100px|<small><center>Fibrinopurulent arthritis in cattle (Image sourced from Bristol Biomed Image Archive with permission)</center></small>]]
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| − | [[Image:Cattle suppurative arthritis.jpg|right|thumb|100px|<small><center>Suppurative arthritis in cattle (Image sourced from Bristol Biomed Image Archive with permission)</center></small>]]
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| − | *Inflammation of intra-articular structures
| + | [[:Category:Arthritis]] |
| − | *In farm animals usually due to infection
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| − | *In small animals usually due to non-infectious causes
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| − | *Classification:
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| − | **According to number of joints involved - '''polyarthritis'''
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| − | **According to type of inflammatory exudate
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| − | ***'''Serous'''
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| − | ****Increased synovial fluid production
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| − | ****Resolves if uncomplicated
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| − | ***'''Fibrinous'''
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| − | ****Early stages:
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| − | *****Increased and more opaque synovial exudate
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| − | *****Enlarged hyperaemic villi
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| − | *****Small haemorrhages in synovial membrane
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| − | ****Later stages:
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| − | *****Less exudate
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| − | *****Thickend synovial connective tissue
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| − | *****Marked villi proliferation (branching in microscopic preparations)
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| − | *****Proliferated synovial tissue -> peripheral fibrous tissue attempting repair across defective surface = '''pannus'''
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| − | ****Mild cases resolve
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| − | ****More severe cases - residual inflammation remains
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| − | ****Most severe cases - organising fibrosis +/- ankylosis
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| − | ***'''Purulent'''
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| − | ****Usually from haemoatogenous spread e.g. neonatal navel ill
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| − | ****May extend from adjacent abscesses
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| − | ****More destructive
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| − | ****Erosion of articular surfaces to underlying bone
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| − | ****Forms abscesses
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| − | ****Possible fistulation to the skin
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| − | *Caused by:
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| − | **Trauma
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| − | **Infectious organisms (e.g. bacteria, viruses)
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| − | **Foreign material (urate crystals = gout)
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| − | **Immune-mediated disease
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| − | ==Infectious arthritis==
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| − | *'''Bacterial arthritis'''
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| − | **Most common in food animals, especially young
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| − | **Portals of entry include:
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| − | ***Navel and GI tract -> bacteraemia
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| − | ***Haematogenously -> polyarthritis
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| − | ***Traumatic inoculation
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| − | ***Extension from bone or periarticular soft tissue
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| − | *'''Viral arthritis'''
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| − | **Progressive inflammatory and degenerative joint disease
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| − | **Synovitis with cartilage destruction
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| − | **Chronic mononuclear inflammatory reactions
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| − | ===In Sheep===
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| − | *[[Retroviridae|'''Maedi visna virus''']]
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| − | *Bacterial infections mostly affects lambs except for Mycoplasmal artheritis
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| − | *[[Erysipelothrix rhusiopathiae|'''''Erysipelothrix rhusiopathiae''''']]
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| − | *'''''[[Corynebacterium pyogenes]]'''''
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| − | *[[:Category:Streptococcus species|'''''Streptococcus'' spp.''']]
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| − | *[[:Category:Staphylococcus species|'''''Staphylococci''''']]
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| − | *[[:Category:Chlamydophila species|'''''Chlamydia sp.''''']]
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| − | ===In Pigs===
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| − | *[[Erysipelas - Pig|'''''Erysipelothrix rhusiopathiae''''']]
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| − | *'''''[[Corynebacterium pyogenes]]''''' and [[:Category:Staphylococcus species|'''''Staphylococci''''']]
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| − | *'''''[[Haemophilus suis]]'' and ''[[Haemophilus parasuis]]'''''
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| − | *'''''[[Mycoplasma hyosynoviae]]'' and ''M. hyorhinis'''''
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| − | ===In Cattle===
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| − | *Neonatal polyarthritis by:
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| − | **[[:Category:Streptococcus species|'''''Streptococcus'' spp.''']]
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| − | ***Via umbilicus
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| − | ***Also involves eyes and meninges
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| − | **[[Escherichia coli|'''''Coliforms''''']]
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| − | ***Localises in joints and meninges in severe non-fatal neonatal colibacillosis
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| − | ***May remain as chronic arthritis in larger joints
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| − | *Infections at any age:
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| − | **'''''[[Corynebacterium pyogenes]]'''''
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| − | ***Suppurative arthrtis
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| − | ***Often due to pebetrating wound into or close to joints
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| − | **[[:Category:Mycoplasmas|'''''Mycoplasma spp.''''']]
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| − | ***May be respinsible for some chronic cases but difficult to prove as hard to isolate
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| − | ***Fibrinous polyarthritis
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| − | **[[:Category:Chlamydophila species|'''''Chlamydia sp.''''']]
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| − | ***Severe disease in young calves
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| − | ***High mortality
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| − | ***Can be seen in smears of synovial fluid from swollen joints
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| − | ***Oedematous and hyperaemic surrounding tissue
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| − | ***Possibly due to intrauterine infection
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| − | **'''''[[Brucella abortus]]'''''
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| − | ***Uncommonly localises in joints
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| − | ***Usually in '''carpal bursitis (hygroma) in cattle and bursitis in horses'''
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| − | ===In Horses===
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| − | *Arthritis can occur following neonatal infections by:
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| − | **'''''[[Actinobacillus equuli]]'''''
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| − | **[[:Category:Streptococcus species|'''''Streptococcus'' spp.''']]
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| − | **[[Escherichia coli|'''''Coliforms''''']]
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| − | **[[Salmonella|'''''Salmonella''''']]
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| − | ===In Goats===
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| − | *[[Caprine Arthrirtis Encephalitis Virus]]
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| − | ===In Dogs===
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| − | *[[:Category:Staphylococcus species|'''''Staphylococci''''']]
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| − | **May cause '''discospondylitis'''
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| − | **Destructive inflammatory lesion
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| − | **Bacterial localise in ''[[Joints - Anatomy & Physiology#Fibrocartilagenous joints|''annulus fibrosis'']] -> may spread to local bone
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| − | ==Non-infectious arthritis==
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| − | *No causative agent has been found
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| − | *Seem to be immune-mediated diseases
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| − | ===Erosive===
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| − | ====Rheumatoid arthritis====
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| − | *Occurs in the dog, mainly smaller breeds
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| − | *Uncommon
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| − | *Progressive erosive polyarthritis
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| − | *Mostly involves elbows, stifles, carpal and tarsal joints
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| − | *Grossly:
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| − | **Marked villus hypertrophy of synovial membrane
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| − | **Cartilage erosion
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| − | **[[Musculoskeletal Terminology - Pathology|Pannus and periarticular osteophyte]] formation
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| − | **In severe cases ankylosis
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| − | *Histologically:
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| − | **Hyperplasia of lining cells
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| − | **Proliferative synovitis
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| − | **Synovial membrane has fibrin deposits
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| − | **Lymphoid and plasma cell infiltration
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| − | **Surrounding haemorrhagic areas
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| − | **Macrophages containing [[Pigmentation - Pathology#Haemosiderin|haemosiderin]]
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| − | **Connective tissue may contain foci of necrosis
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| − | **Areas of erosion of peripheral articular cartilage and underlying subchondral bone
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| − | *Pathogenesis:
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| − | **May involve deposition of immune complexes within joints
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| − | **Substances degrading cartilage are released by synovial cells and macrophages involved in pannus formation
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| − | ===Non-erosive===
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| − | ====Systemic lupus erythematosus (SLE)====
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| − | *Occurs in dogs
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| − | *Clinical signs:
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| − | **Anaemia
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| − | **Thrombocytopaenia
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| − | **[[Muscles Inflammatory - Pathology#Myositis|Polymyositis]]
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| − | **[[Kidney Glomerular Disease - Pathology#Glomerulonephritis|Glomerulonephritis]]
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| − | ====In chronic diseases====
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| − | *E.g. pyometra, otitis externa, [[Endocarditis|endocarditis]], [[:Category:Intestine - Inflammatory Pathology|enteritis]]
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| − | *Can lead to immune complex deposition in joints
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| − | ====Gout====
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| − | *Occurs in humans, reptiles and birds (have no uricase enzyme)
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| − | *The urate triggers inflammation
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| | [[Category:Musculoskeletal System - Pathology]] | | [[Category:Musculoskeletal System - Pathology]] |