Difference between revisions of "Bones Inflammatory - Pathology"

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#REDIRECT[[:Category:Bones - Inflammatory Pathology]]
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{{review}}
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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=Bones - Pathology
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|subtext1=BONES
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<br>
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===Bone infections in general===
 +
 +
*'''Caused by''':
 +
**Bacteria most commonly (e.g. [[Teeth - Pathology#Mandibular Osteomyelitis|lumpy jaw]] in cattle due to ''[[Actinomyces bovis]]'')
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**Viruses, fungi and protozoa less commonly
 +
 
 +
*'''Routes of infection''':
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**“Inoculated” at time of [[Bones Fractures - Pathology|fracture]]
 +
**Extension from other infected sites ([[Paranasal Sinuses Inflammatory - Pathology|sinuses]], middle ear, [[Joints Inflammatory - Pathology|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, [[Teeth - Pathology#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 - Pathology#Arthritis|suppurative arthritis]]
 +
*Usually isolated: ''[[Actinomyces pyogenes]]'', [[Salmonella|''Salmonella'']], [[Escherichia coli|''E.coli'']], [[Klebsiella|''Klebsiella'']], [[:Category:Streptococcus species|''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 [[Chronic Inflammation - Pathology#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 ''[[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
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**Caused by ''[[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
 +
***[[Teeth - Pathology#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 - Pathology#Hypertrophic osteodystrophy|'''hypertrophic osteodystrophy''']]

Revision as of 10:55, 17 May 2010

 This article has been peer reviewed but is awaiting expert review. If you would like to help with this, please see more information about expert reviewing.


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()Map MUSCULOSKELETAL SYSTEM (Map)
BONES



Bone infections in general

  • Routes of infection:
    • “Inoculated” at time of fracture
    • Extension from other infected sites (sinuses, middle ear, 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

Osteomyelitis

Localised osteomyelitis plus sequestrum (Image sourced from Bristol Biomed Image Archive with permission)
  • Mainly due to haematogenous spread in young animals
  • Often as an extension from suppurative arthritis
  • Usually isolated: Actinomyces pyogenes, Salmonella, E.coli, Klebsiella, Streptococci
  • Metaphyses and epiphyses mostly affected
  • Most infections are exacerbated by host response
  • Pathogenesis:
    • Prostaglandin and cytokines stimulate 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 granulation tissue
    • Isolated from osteoclastic resorption
    • May persist for long time
    • Obstruct repair


  • Vertebral osteomyelitis
    • Lesions may affect the spinal cord
    • Usually due to 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 Actinomyces bovis
      • Gram positive, branching, filamentous
      • Obligatory parasite of mucous membranes of oropharynx
      • Surface tissue is usually injured for infection to occur
      • 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
      • Excessive periosteal bone formation
      • Greatly enlarged mandible

Periostitis

  • Chronic periostitis - pockets of exudate and irregular new bone fomation

Panosteitis

Panosteitis (Image sourced from Bristol Biomed Image Archive with permission)
  • 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 hypertrophic osteodystrophy
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