Difference between revisions of "Bones Degenerative - Pathology"

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#REDIRECT[[:Category:Bones - Degenerative Pathology]]
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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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}}
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<br>
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<big>
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[[Bones Metabolic - Pathology|'''Bones and Cartilage - Metabolic diseases''']]
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[[Bones Fractures - Pathology|'''Bones and Cartilage - Fractures''']]
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</big>
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===Osteoporosis (Atrophy)===
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*Lesion, not a disease
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*Reduction in bone mass due to reduced osteoid (bone atrophy)
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*Bone resorption exceeds formation -> pathological loss of bone
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*Resorbed from:
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**Trabeculae, preserving the weight bearing ones until last
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**Endosteal surface of cortical bone
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**Along vascular channels
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*Longitudinal section
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**Fewer thin trabeculae
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**Enlarged medulla
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**Thin, porous cortex
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*Bone which remains is normally mineralised
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*Can be localised or generalised*Caused by:
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**Starvation - in farm animals due to protein and energy deficiency
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**Nutritional deficiency (calcium) and hypocalcaemia -> bone resorption
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**Senility
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***Physiological loss of skeletal mass with age
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***May be excessive in some individuals
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***Histologically - dead [[Bones - normal#Normal stucture|osteocytes and empty lacunea]]
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**Physical inactivity (disuse) - muscular inactivity and reduced weight bearing, e.g. during limb casting
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**Glucocorticoids
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**[[Intestine - Parasites|Intestinal parasitism]] - in ruminants, malabsorption due to severe infestation
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**[[General Pathology - Congenital and Neonatal Disease#Copper Deficiency|Copper deficiency]] - in lambs, calves, foals, pigs and dogs -> brittle bones
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*May be reversed in young growing animals
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 +
 
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===Osteosis===
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*Also called '''Aseptic necrosis''' or '''Ischaemic necrosis'''
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*Degeneration and necrosis of osseous tissue
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*Due to bone marrow pressure and ischaemia resulting from
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**[[Bones Fractures - Pathology|Fractures]]
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**Excessive heat e.g. horn disbudding
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**Neoplasia ([[Bones Hyperplastic and Neoplastic - Pathology#Osteosarcoma|osteosarcoma]] and [[Bones Hyperplastic and Neoplastic - Pathology#Lymphosarcoma|lymphosarcoma]])
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*Grossly:
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**Necrotic bone difficult to recognise
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**Sometimes, periosteum becomes dry, dull and detaches easily
 +
**On longitudinal section
 +
***Yellow-white necrotic bone
 +
***Scattered cancellous and endosteal bone
 +
*Histologically:
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**Empty [[Bones - normal#Normal structure|lacunae or contain dead osteocytes]]
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**Matrix remains mineralised
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*Necrotic bone is slowly resorbed, sequstered or covered by new woven bone
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*Persists
 +
*May not be detected radiographically
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*Associated with [[Joints Degenerative - Pathology#Calve Legg-Perthe's disease|Calve-Legg Perthe's disease]]
 +
 
 +
 
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===Bone cysts===
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[[Image:Bone cysts dog.jpg|right|thumb|100px|<small><center>Bone cysts (Image sourced from Bristol Biomed Image Archive with permission)</center></small>]]
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*May be seen radiographically
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*Must be distinguished from [[Bones Hyperplastic and Neoplastic - Pathology#Neoplastic|neoplasia]]
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*Expansile lytic masses
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*Do not appear aggressive
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*'''Subchondral cysts'''
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**Common in horses and pigs
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**Usually manifestations of [[Joints Developmental - Pathology#Osteochondrosis|osteochondrosis]] and [[Joints Degenerative - Pathology#Degenerative joint disease (DJD)|DJD]]
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*'''Simple cysts'''
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**May contain clear colourless fluid, or serosanguinous
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**Wall of dense fibrous tissue, [[Bones - normal#Bone organisation|woven or lamellar bone]]
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*'''Aneurysmal bone cysts'''
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**Expansie lesions
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**Arise from disturbance of vascular tissue of bone marrow
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**Grossly:
 +
***Appear as blood filled sponge
 +
***Spaces separated by fibrous trabeculae
 +
**Histologically:
 +
***Proliferation of undifferentiated mesenchymal cell with multinucleated osteoclast-like cells
 +
***Haemorrhage and haemosiderosis
 +
*Radiography is essential to help differentiate with cavity of a neoplasm
 +
 
 +
 
 +
===Calcium hydroxylapatite deposition disease===
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*Gt Dane puppies with paraplegia
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*Calcium phosphate depositon has been reported in multiple diarthrodial joints of the axial and appendicular skeleton
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*[[More on Calcium hydroxylapatite deposition disease|More about Calcium hydroxylapatite deposition disease]]
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 +
 
 +
===Physeal dysplasia with slipped capital femoral epiphysis===
 +
 
 +
*Slipped capital femoral epiphysis seen in dogs, foals and calves
 +
*Associated with severe trauma
 +
*Pigs – manifestation of [[Joints Developmental - Pathology#Osteochondrosis|osteochondrosis]] with only minimal trauma required
 +
*Most common type of physeal fracture in small animals and the proximal femur is the most common site
 +
*In horses, physeal dysplasia is synonymus with [[Bones Developmental - Pathology#Physitis|physitis]]
 +
*[[More about Physeal dysplasia]]

Revision as of 19:45, 18 August 2008

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()Map MUSCULOSKELETAL SYSTEM (Map)
BONES



Bones and Cartilage - Metabolic diseases

Bones and Cartilage - Fractures

Osteoporosis (Atrophy)

  • Lesion, not a disease
  • Reduction in bone mass due to reduced osteoid (bone atrophy)
  • Bone resorption exceeds formation -> pathological loss of bone
  • Resorbed from:
    • Trabeculae, preserving the weight bearing ones until last
    • Endosteal surface of cortical bone
    • Along vascular channels
  • Longitudinal section
    • Fewer thin trabeculae
    • Enlarged medulla
    • Thin, porous cortex
  • Bone which remains is normally mineralised
  • Can be localised or generalised*Caused by:
    • Starvation - in farm animals due to protein and energy deficiency
    • Nutritional deficiency (calcium) and hypocalcaemia -> bone resorption
    • Senility
    • Physical inactivity (disuse) - muscular inactivity and reduced weight bearing, e.g. during limb casting
    • Glucocorticoids
    • Intestinal parasitism - in ruminants, malabsorption due to severe infestation
    • Copper deficiency - in lambs, calves, foals, pigs and dogs -> brittle bones
  • May be reversed in young growing animals


Osteosis

  • Also called Aseptic necrosis or Ischaemic necrosis
  • Degeneration and necrosis of osseous tissue
  • Due to bone marrow pressure and ischaemia resulting from
  • Grossly:
    • Necrotic bone difficult to recognise
    • Sometimes, periosteum becomes dry, dull and detaches easily
    • On longitudinal section
      • Yellow-white necrotic bone
      • Scattered cancellous and endosteal bone
  • Histologically:
  • Necrotic bone is slowly resorbed, sequstered or covered by new woven bone
  • Persists
  • May not be detected radiographically
  • Associated with Calve-Legg Perthe's disease


Bone cysts

Bone cysts (Image sourced from Bristol Biomed Image Archive with permission)
  • May be seen radiographically
  • Must be distinguished from neoplasia
  • Expansile lytic masses
  • Do not appear aggressive
  • Subchondral cysts
  • Simple cysts
  • Aneurysmal bone cysts
    • Expansie lesions
    • Arise from disturbance of vascular tissue of bone marrow
    • Grossly:
      • Appear as blood filled sponge
      • Spaces separated by fibrous trabeculae
    • Histologically:
      • Proliferation of undifferentiated mesenchymal cell with multinucleated osteoclast-like cells
      • Haemorrhage and haemosiderosis
  • Radiography is essential to help differentiate with cavity of a neoplasm


Calcium hydroxylapatite deposition disease


Physeal dysplasia with slipped capital femoral epiphysis

  • Slipped capital femoral epiphysis seen in dogs, foals and calves
  • Associated with severe trauma
  • Pigs – manifestation of osteochondrosis with only minimal trauma required
  • Most common type of physeal fracture in small animals and the proximal femur is the most common site
  • In horses, physeal dysplasia is synonymus with physitis
  • More about Physeal dysplasia
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