Difference between revisions of "Bones Developmental - Pathology"

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===Osteogenesis Imperfecta===
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===[[Osteogenesis Imperfecta]]===
  
*Cause of fragile bones in humans, very rarely in animals
 
*Reported in Holstein and Charolais calves
 
*Poor mineralisation of bones and teeth
 
*Fractures are often present at birth
 
 
 
[[Category:Bones - Developmental Pathology]]
 
  
  

Revision as of 18:02, 27 February 2011

Generalised

Dwarfism


Chondrodysplasia

Osteopetrosis

Lysosomal Storage Disease

Osteogenesis Imperfecta

Congenital hyperostosis of pigs

Hyperostosis (Image sourced from Bristol Biomed Image Archive with permission)
  • Rare, genetic
  • Diaphysial dysplasia
  • Excessive periosteal intramembranous bone, particularly in long bones
  • Grossly:
    • Greatly thickened long bones
    • Tense, shiny skin, closely adherent to tissues below
  • Born dead or die soon after birth


Retention of elongated primary trabeculae

  • Happens due to impaired osteoclastic activity
  • Primary trabeculae do not transform into secondary and tertiary
  • Continue to elongate
  • Form a dense band beneath growth plate - growth retardation lattice
  • Dense spikules apparent on radiographs
  • Can be caused by distemper virus, bovine viral diarrhoea virus


Localised

  • Hemimelia - abscence of one of limb bones
  • Syndactylia - fusion of toes
  • Polydactylia - increased number of digits
  • Ectrodactylia - cleft in paw extending to metacarpus of dogs and cats


Cervical Vertebral Stenotic Myelopathy (Wobblers)

  • Equine disease
  • Narrowing of the vertebral canal due to malalignment or maldevelopment of the vertebrae
  • Fast growing male TBs ranging from 8 months to 4 years
  • Hind limb ataxia due to cord compression


Angular limb deformity

  • Lateral deviation of distal portion of limb (valgus)
  • Medial deviation of distal portion of limb (varus) - more rare
  • Most common in foals
    • Carpal joint
    • Tarsal joint
    • Fetlock joint
  • Congenital or acquired
  • Due to:
    • Malpositioning in utero
    • Excessive joint laxity
    • Hypothyroidism
    • Trauma
    • Overnutrition
    • Defective endochondral ossification
    • Poor conformation
    • Disruption of blood supply to one side of bone
    • Secondary to physitis in horses
  • Usually resolves spontaneously in one to two weeks of life
  • More severe cases exceding compensatory capabilities will persisist
  • Cartilage development is affected


Fibrous dysplasia


Physitis

  • In horses
  • Often associated with angular limb deformity
  • Also called epiphysitis and physeal dysplasia
  • Problem of endochondral ossification
  • Two age groups
    • Weanlings
    • Yearlings in early training and two-year-olds
  • May cause contracted tendons and flexural deformities
  • Factors probably involved in its development:
    • Genetically fast growth rate
    • Large quantities of imbalanced, high energy feed
    • Imbalanced weight-bearing on joints
    • Excessive activity
    • Growth spurts
  • Histologically: (appearance similar to angular limb deformity)
    • Lateral aspect of radius
      • Thickened metaphyseal part of physeal cartilage
      • -> Delay or disturbance of endochondral ossification
      • Compression
    • Central part
      • No obvious deformity
    • Medial aspect
    • Laxity of periarticular attachements in young foals allows angular limb deformity; not occuring in older foals and young horses
    • (Sustained trauma produces similar lesions)



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Developmental abnormalities