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| − | {{review}}
| + | #redirect[[:Category:Arthritis]] |
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| − | {{toplink
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| − | |backcolour =CDE472
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| − | |linkpage =Musculoskeletal System - Pathology
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| − | |linktext =Musculoskeletal System
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| − | |maplink = Musculoskeletal System (Content Map) - Pathology
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| − | |pagetype =Pathology
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| − | |sublink1=Joints - Pathology
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| − | |subtext1=JOINTS
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| − | }}
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| − | <br>
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| − | ==Arthritis==
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| − | [[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
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| − | *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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| − | **Clinical sighns:
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| − | ***Cutaneous erysipelas
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| − | ***Polyarthritis in lambs
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| − | ***Rarely fatal septicaemia
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| − | **Enters via:
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| − | ***Cuts, abrasions
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| − | ***Castration or docking wounds
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| − | ***Haematogenous spread -> subacute or chronic '''fibrinopurulent polyarthritis'''
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| − | **Morbidity up tp 50%
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| − | **Affects mostly unthrifty lmbs
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| − | **Fibrosis and [[Musculoskeletal Terminology - Pathology|osteophyte]] formation in later stages -> persistent lameness
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| − | *[[Corynebacterium species|'''''Corynebacterium pyogenes''''']]
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| − | **May cause post-dipping joint infections
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| − | *[[Streptococci|'''''Streptococcus'' spp.''']]
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| − | **Commonly cause suppurative polyarthritis in lambs
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| − | **Naval infection -> bacteriamia -> polyarthritis
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| − | ***May also cause blindness and nervous signs if uvea or meninges are affected
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| − | **Larger joints are more afected
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| − | ***May spread to other organs
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| − | *[[Staphylococcus spp.|'''''Staphylococci''''']]
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| − | **Sporadically infect joints
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| − | **May complicate 'tick-borne fever'
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| − | *[[Chlamydia and Chlamydophila species|'''''Chlamydia sp.''''']]
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| − | **Sporadic or outbreaks of lamb polyarthritis
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| − | **High morbidity, low mortality
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| − | **Commonly together with conjunctivitis
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| − | **Most recover but may remain lame
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| − | ===In Pigs===
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| − | *[[Erysipelothrix rhusiopathiae|'''''Erysipelothrix rhusiopathiae''''']]
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| − | **Most important and most common cause of arthritis
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| − | **Causes '''chronic serofibrinous polyarthritis'''
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| − | **Also causes '''discospondylitis'''
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| − | ***Similar to [[Joints Inflammatory - Pathology#In Dogs|discospondylitis in dogs]]
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| − | **Thickening of synovial membrane lining + plus hyperaemia and villus formation + lymphocyte and plasma cell infiltration
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| − | **Acute stage
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| − | ***Increased joint fluid + hot swollen joints
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| − | ***Also expresses as septicaemic and urticarial lesion on the back (diamond shaped)
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| − | ***May involve [[Endocardial - Pathology#Inflammatory-Endocarditis|endocarditis]] as a sequel
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| − | **Chronic stage
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| − | ***More commonly encountered
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| − | ***Erosion of articular surface of joints with formation of [[Musculoskeletal Terminology - Pathology|pannus +/- joint ankylosis]]
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| − | ***Vaccination prevents septicaemic and urticarial forms but has no effect on joints
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| − | ****Probably due to dead bacteria still stimulating host immune system
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| − | **Septicaemia lo9calises in meninges and joints
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| − | **Well known in piglets in their first two months of life
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| − | **Expresses as acute '''fibrinopurulent''' arthritis
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| − | *[[Corynebacterium species|'''''Corynebacterium pyogenes''''']] and [[Staphylococcus spp.|'''''Staphylococci''''']]
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| − | **Cause purulent arthritis
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| − | **In one or more joints
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| − | **Commonly contaminate wounds
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| − | *[[Haemophilus species|'''''Haemophilus suis'' and ''H. parasuis''''']]
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| − | **Cause Glasser's disease
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| − | **Fibrinous polyserositis, polyarhritis, meningitis
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| − | *[[Mycoplasmas|'''''Mycoplasma hyosynovia'' and ''M. hyorhinis''''']]
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| − | **Produce syndrome similar to [[Haemophilus species|Glasser's disease]] with milder expression
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| − | **Menigitis is rare
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| − | **Arthritis most consistent
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| − | ===In Cattle===
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| − | *Neonatal polyarthritis by:
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| − | **[[Streptococci|'''''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 sevee 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 species|'''''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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| − | **[[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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| − | **[[Chlamydia and 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 species|'''''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 species|'''''Actinobacillus equuli''''']]
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| − | **[[Streptococci|'''''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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| − | **Arthritis is commonly the main expression
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| − | **Large limb joints are thickened
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| − | **'''Carpal hygroma''' is often present
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| − | ***Subcutaneous cystic swelling on cranial surface of the knee, contains serous fluid
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| − | **In advanced cases
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| − | ***Synovial villus hypertrophy
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| − | ***Necrosis
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| − | ***Mineralisation
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| − | ***Mononuclear cell infiltration
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| − | ***[[Musculoskeletal Terminology - Pathology|Pannus]] formation
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| − | ***[[Joints - Anatomy & Physiology#Articular cartilage|Articular cartilage]] destruction
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| − | ===In Dogs===
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| − | *[[Staphylococcus spp.|'''''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 [[General Pathology - Pigmentation and Calcification#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, [[Endocardial - Pathology|endocarditis]], [[Intestine Inflammatory - Pathology#Inflammation - Contents|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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