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[[Osteitis]]
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#REDIRECT[[:Category:Bones - Inflammatory Pathology]]
 
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===Osteomyelitis===
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[[Image:Cattle localised osteomyelitis with sequestrum.jpg|right|thumb|100px|<small><center>Localised osteomyelitis plus sequestrum (Image sourced from Bristol Biomed Image Archive with permission)</center></small>]]
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*Mainly due to haematogenous spread in young animals
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*Often as an extension from [[Joints Inflammatory - Pathology#Arthritis|suppurative arthritis]]
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*Usually isolated: ''[[Actinomyces pyogenes]]'', [[Salmonella|''Salmonella'']], [[Escherichia coli|''E.coli'']], [[Klebsiella|''Klebsiella'']], [[:Category:Streptococcus species|''Streptococci'']]
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*Metaphyses and epiphyses mostly affected
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*Most infections are exacerbated by host response
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*Pathogenesis:
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**Prostaglandin and cytokines stimulate [[Bones - Anatomy & Physiology|osteoclastic]] bone resorption
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**Blood vessel occlusion and tissue necrosis -> lack of removal of agent and cartilage -> cartilage thickening + persistance of infection
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*Affected area may be surrounded by fibrous inflammatory tissue
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*Metaphyseal abscesses may develop
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*Sequestra may also develop -> surrounded by [[Granulation Tissue|granulation tissue]]
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**Isolated from osteoclastic resorption
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**May persist for long time
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**Obstruct repair
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*'''Vertebral osteomyelitis'''
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**Lesions may affect the spinal cord
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**Usually due to ''[[Actinomyces pyogenes]]''
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**Suppurative inflammation may cause fracture of vertebral body -> dorsal displacement -> damage to spinal cord
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**May form encapsulated abscess protruding into spinal canal -> spinal cord compression
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*'''''Actinomycosis'''''
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**= '''Lumpy jaw''' in cattle
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**Caused by ''[[Actinomyces bovis]]''
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***Gram positive, branching, filamentous
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***Obligatory parasite of mucous membranes of [[Oropharynx - Anatomy & Physiology|oropharynx]]
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***Surface tissue is usually injured for infection to occur
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***[[Mandibular Osteomyelitis|Osteomyelitis of mandible]] -> destruction of bone -> replacement by fibrous tissue with pyogranulomatous nodules cotaining 'club colonies' of bacteria
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***Suppurative osteomyelitis
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***Fistulous tracts may discharge onto skin and into [[Oral Cavity Overview - Anatomy & Physiology|oral cavity]]
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***Excessive periosteal bone formation
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***Greatly enlarged mandible
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[[Category:Bones - Inflammatory Pathology]]
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===Periostitis===
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*Chronic periostitis - pockets of exudate and irregular new bone fomation
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[[Category:Bones - Inflammatory Pathology]]
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===Panosteitis===
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[[Image:Panosteitis.jpg|right|thumb|100px|<small><center>Panosteitis (Image sourced from Bristol Biomed Image Archive with permission)</center></small>]]
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*Typically young large or giant breeds
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*75% of cases in German shepherd dogs, 5-12 months old
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*Clinical signs:
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**Shifting lameness
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**Often eosinophilia in peripheral blood
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*Usually self-limiting in one to several months
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*Grossly:
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**Foreleg long bone '''diaphyses''' affected (multiple bones in 50% of cases)
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**Increased bone formation in the medullary cavity and often in the periosteum
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*Contast with [[Bones Hyperplastic and Neoplastic - Pathology#Hypertrophic osteodystrophy|'''hypertrophic osteodystrophy''']]
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[[Category:Bones - Inflammatory Pathology]]
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[[Category:Musculoskeletal System - Pathology]]
 
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