Difference between revisions of "Bones Degenerative - Pathology"
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*'''Subchondral cysts''' | *'''Subchondral cysts''' | ||
**Common in horses and pigs | **Common in horses and pigs | ||
| − | **Usually manifestations of [[Joints - | + | **Usually manifestations of [[Joints Developmental - Pathology#Osteochondrosis|osteochondrosis]] and [[Joints - degenerative#Degenerative joint disease (DJD)|DJD]] |
*'''Simple cysts''' | *'''Simple cysts''' | ||
**May contain clear colourless fluid, or serosanguinous | **May contain clear colourless fluid, or serosanguinous | ||
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*Slipped capital femoral epiphysis seen in dogs, foals and calves | *Slipped capital femoral epiphysis seen in dogs, foals and calves | ||
*Associated with severe trauma | *Associated with severe trauma | ||
| − | *Pigs – manifestation of [[Joints - | + | *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 | *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]] | *In horses, physeal dysplasia is synonymus with [[Bones Developmental - Pathology#Physitis|physitis]] | ||
*[[More about Physeal dysplasia]] | *[[More about Physeal dysplasia]] | ||
Revision as of 19:42, 18 August 2008
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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
- Physiological loss of skeletal mass with age
- May be excessive in some individuals
- Histologically - dead osteocytes and empty lacunea
- 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
- Fractures
- Excessive heat e.g. horn disbudding
- Neoplasia (osteosarcoma and lymphosarcoma)
- 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:
- Empty lacunae or contain dead osteocytes
- Matrix remains mineralised
- 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
- May be seen radiographically
- Must be distinguished from neoplasia
- Expansile lytic masses
- Do not appear aggressive
- Subchondral cysts
- Common in horses and pigs
- Usually manifestations of osteochondrosis and DJD
- Simple cysts
- May contain clear colourless fluid, or serosanguinous
- Wall of dense fibrous tissue, woven or lamellar bone
- 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
- Gt Dane puppies with paraplegia
- Calcium phosphate depositon has been reported in multiple diarthrodial joints of the axial and appendicular skeleton
- More about 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