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Joints Inflammatory - Pathology (view source)

Revision as of 19:47, 18 August 2008

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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|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#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|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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*[[Retroviridae|'''Caprine arthritis/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|Pannus]] formation
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***[[Joints - normal#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 - normal#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|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#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#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
Retrieved from "https://en.wikivet.net/Special:MobileDiff/28812"

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