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Bones Inflammatory - Pathology (view source)
Revision as of 19:23, 18 August 2008
, 19:23, 18 August 2008New page: {{toplink |backcolour =CDE472 |linkpage =Musculoskeletal System - Pathology |linktext =Musculoskeletal System |maplink = Musculoskeletal System (Content Map) - Pathology |pagetype =Patholo...
{{toplink
|backcolour =CDE472
|linkpage =Musculoskeletal System - Pathology
|linktext =Musculoskeletal System
|maplink = Musculoskeletal System (Content Map) - Pathology
|pagetype =Pathology
|sublink1=Bones - Pathology
|subtext1=BONES
}}
<br>
===Bone infections in general===
*'''Caused by''':
**Bacteria most commonly (e.g. [[Oral Cavity - Teeth#Mandibular Osteomyelitis|lumpy jaw]] in cattle due to [[Actinomycetes|''Actinomyces bovis'']])
**Viruses, fungi and protozoa less commonly
*'''Routes of infection''':
**“Inoculated” at time of [[Bones Fractures - Pathology|fracture]]
**Extension from other infected sites ([[Paranasal Sinuses Inflammatory - Pathology|sinuses]], middle ear, [[Joints - inflammatory|joints]])
**Haematogenous (young farm animals)
*'''Gross lesions'''
**Suppurative exudate (in bacterial infection), necrosis, bone proliferation, pathological fractures
**Dead bone portions may be separated from blood supply and form bone sequestra
*'''Consequences'''
**Extension to adjacent bone
**Haematogenous spread to other bones and soft tissue
**Pathologic fractures
**Sinus tracts to exterior
*'''Osteitis''' = inflammation of bone
*'''Periostitis''' = inflammation of periosteum, usually develops from infection in adjacent tissues
*'''Osteomyelitis''' = inflammation of medullary cavity
===Osteitis===
*E.g.: [[Fusobacterium|''Fusobacterium necrophorum'']] in the foot, [[Respiratory Bacterial Infections - Pathology#Necrotic laryngitis|calf diphteria]], bite wounds, extension from paranasal sinuses, compound fractures, extensions from infections in the joints, [[Oral Cavity - Teeth#Alveolar Periostitis|periodontal disease]], [[Respiratory Bacterial Infections - Pathology#Atrophic Rhinitis|Atrophic rhinitis]]
===Osteomyelitis===
[[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>]]
*Mainly due to haematogenous spread in young animals
*Often as an extension from [[Joints - inflammatory#Arthritis|suppurative arthritis]]
*Usually isolated: [[Actinomycetes|''Actinomyces pyogenes'']], [[Salmonella|''Salmonella'']], [[Escherichia coli|''E.coli'']], [[Klebsiella|''Klebsiella'']], [[Streptococci|''Streptococci'']]
*Metaphyses and epiphyses mostly affected
*Most infections are exacerbated by host response
*Pathogenesis:
**Prostaglandin and cytokines stimulate [[Bones - normal#Normal structure|osteoclastic]] bone resorption
**Blood vessel occlusion and tissue necrosis -> lack of removal of agent and cartilage -> cartilage thickening + persistance of infection
*Affected area may be surrounded by fibrous inflammatory tissue
*Metaphyseal abscesses may develop
*Sequestra may also develop -> surrounded by [[General Pathology - Chronic Inflammation#Granulation Tissue|granulation tissue]]
**Isolated from osteoclastic resorption
**May persist for long time
**Obstruct repair
*'''Vertebral osteomyelitis'''
**Lesions may affect the spinal cord
**Usually due to [[Actinomycetes|''Actinomyces pyogenes'']]
**Suppurative inflammation may cause fracture of vertebral body -> dorsal displacement -> damage to spinal cord
**May form encapsulated abscess protruding into spinal canal -> spinal cord compression
*'''''Actinomycosis'''''
**= '''Lumpy jaw''' in cattle
**Caused by [[Actinomycetes|''Actinomyces bovis'']]
***Gram positive, branching, filamentous
***Obligatory parasite of mucous membranes of [[Oral Cavity - Oropharynx - Anatomy & Physiology|oropharynx]]
***Surface tissue is usually injured for infection to occur
***[[Oral Cavity - Teeth#Mandibular Osteomyelitis|Osteomyelitis of mandible]] -> destruction of bone -> replacement by fibrous tissue with pyogranulomatous nodules cotaining 'club colonies' of bacteria
***Suppurative osteomyelitis
***Fistulous tracts may discharge onto skin and into [[Oral Cavity Overview - Anatomy & Physiology|oral cavity]]
***Excessive periosteal bone formation
***Greatly enlarged mandible
===Periostitis===
*Chronic periostitis - pockets of exudate and irregular new bone fomation
===Panosteitis===
[[Image:Panosteitis.jpg|right|thumb|100px|<small><center>Panosteitis (Image sourced from Bristol Biomed Image Archive with permission)</center></small>]]
*Typically young large or giant breeds
*75% of cases in German shepherd dogs, 5-12 months old
*Clinical signs:
**Shifting lameness
**Often eosinophilia in peripheral blood
*Usually self-limiting in one to several months
*Grossly:
**Foreleg long bone '''diaphyses''' affected (multiple bones in 50% of cases)
**Increased bone formation in the medullary cavity and often in the periosteum
*Contast with [[Bones - hyperplastic and neoplastic#Hypertrophic osteodystrophy|'''hypertrophic osteodystrophy''']]
|backcolour =CDE472
|linkpage =Musculoskeletal System - Pathology
|linktext =Musculoskeletal System
|maplink = Musculoskeletal System (Content Map) - Pathology
|pagetype =Pathology
|sublink1=Bones - Pathology
|subtext1=BONES
}}
<br>
===Bone infections in general===
*'''Caused by''':
**Bacteria most commonly (e.g. [[Oral Cavity - Teeth#Mandibular Osteomyelitis|lumpy jaw]] in cattle due to [[Actinomycetes|''Actinomyces bovis'']])
**Viruses, fungi and protozoa less commonly
*'''Routes of infection''':
**“Inoculated” at time of [[Bones Fractures - Pathology|fracture]]
**Extension from other infected sites ([[Paranasal Sinuses Inflammatory - Pathology|sinuses]], middle ear, [[Joints - inflammatory|joints]])
**Haematogenous (young farm animals)
*'''Gross lesions'''
**Suppurative exudate (in bacterial infection), necrosis, bone proliferation, pathological fractures
**Dead bone portions may be separated from blood supply and form bone sequestra
*'''Consequences'''
**Extension to adjacent bone
**Haematogenous spread to other bones and soft tissue
**Pathologic fractures
**Sinus tracts to exterior
*'''Osteitis''' = inflammation of bone
*'''Periostitis''' = inflammation of periosteum, usually develops from infection in adjacent tissues
*'''Osteomyelitis''' = inflammation of medullary cavity
===Osteitis===
*E.g.: [[Fusobacterium|''Fusobacterium necrophorum'']] in the foot, [[Respiratory Bacterial Infections - Pathology#Necrotic laryngitis|calf diphteria]], bite wounds, extension from paranasal sinuses, compound fractures, extensions from infections in the joints, [[Oral Cavity - Teeth#Alveolar Periostitis|periodontal disease]], [[Respiratory Bacterial Infections - Pathology#Atrophic Rhinitis|Atrophic rhinitis]]
===Osteomyelitis===
[[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>]]
*Mainly due to haematogenous spread in young animals
*Often as an extension from [[Joints - inflammatory#Arthritis|suppurative arthritis]]
*Usually isolated: [[Actinomycetes|''Actinomyces pyogenes'']], [[Salmonella|''Salmonella'']], [[Escherichia coli|''E.coli'']], [[Klebsiella|''Klebsiella'']], [[Streptococci|''Streptococci'']]
*Metaphyses and epiphyses mostly affected
*Most infections are exacerbated by host response
*Pathogenesis:
**Prostaglandin and cytokines stimulate [[Bones - normal#Normal structure|osteoclastic]] bone resorption
**Blood vessel occlusion and tissue necrosis -> lack of removal of agent and cartilage -> cartilage thickening + persistance of infection
*Affected area may be surrounded by fibrous inflammatory tissue
*Metaphyseal abscesses may develop
*Sequestra may also develop -> surrounded by [[General Pathology - Chronic Inflammation#Granulation Tissue|granulation tissue]]
**Isolated from osteoclastic resorption
**May persist for long time
**Obstruct repair
*'''Vertebral osteomyelitis'''
**Lesions may affect the spinal cord
**Usually due to [[Actinomycetes|''Actinomyces pyogenes'']]
**Suppurative inflammation may cause fracture of vertebral body -> dorsal displacement -> damage to spinal cord
**May form encapsulated abscess protruding into spinal canal -> spinal cord compression
*'''''Actinomycosis'''''
**= '''Lumpy jaw''' in cattle
**Caused by [[Actinomycetes|''Actinomyces bovis'']]
***Gram positive, branching, filamentous
***Obligatory parasite of mucous membranes of [[Oral Cavity - Oropharynx - Anatomy & Physiology|oropharynx]]
***Surface tissue is usually injured for infection to occur
***[[Oral Cavity - Teeth#Mandibular Osteomyelitis|Osteomyelitis of mandible]] -> destruction of bone -> replacement by fibrous tissue with pyogranulomatous nodules cotaining 'club colonies' of bacteria
***Suppurative osteomyelitis
***Fistulous tracts may discharge onto skin and into [[Oral Cavity Overview - Anatomy & Physiology|oral cavity]]
***Excessive periosteal bone formation
***Greatly enlarged mandible
===Periostitis===
*Chronic periostitis - pockets of exudate and irregular new bone fomation
===Panosteitis===
[[Image:Panosteitis.jpg|right|thumb|100px|<small><center>Panosteitis (Image sourced from Bristol Biomed Image Archive with permission)</center></small>]]
*Typically young large or giant breeds
*75% of cases in German shepherd dogs, 5-12 months old
*Clinical signs:
**Shifting lameness
**Often eosinophilia in peripheral blood
*Usually self-limiting in one to several months
*Grossly:
**Foreleg long bone '''diaphyses''' affected (multiple bones in 50% of cases)
**Increased bone formation in the medullary cavity and often in the periosteum
*Contast with [[Bones - hyperplastic and neoplastic#Hypertrophic osteodystrophy|'''hypertrophic osteodystrophy''']]