Development/metabolic Bone Dz Flashcards
Osteopetrosis
“-petrosis” = thickening –> diffuse osteosclerosis
- hereditable abnormal osteoclast resorption
- -> Primary trabeculae w/ cartilage filled cores in medullary cavity –> obliteration of medullary cavity
Osteogenesis Imperfecta
- hereditary mutant Type 1 collagen –> osteopenia
- Dachshund : SERPINh1 gene –> lack of collagen stabilization
- reduced trabecular bone (lack of O-clast activity)
- Woven bone in cortex (delayed compaction
**Teeth = PINK (disorganized dentin)
Congenital cortical Hyperostosis
- Disorganized of perichondral ossification grove
- -> woven bone perpendicular to long axis of bone
-Neonate pigs
Craniomandibular osteopathy
-hereditary thickening of periosteal woven bone in Mandible, Occipital, & Temporal bones
- -> Osteoblast prolif –> Trabecular Osteo-sclerosis
- Cortical bone = Thick woven bone + lamellar
-Autosomal recessive = Westies
Chondrodysplasias
- Hereditary disorder of Growth plates
- Trabecular bone thickened w/ lateral bridging
- Retained cartilage cores
- Short-leg, normal head-size
- Basset, Dachshund, Pekingese
- FGF4 mutation - Primordial Dwarfism (proportional reduction)
- Mini schnauzers, Min Pins, Miniature poodles - Spider Lamb
- mutant FGFR3–> mutant Tyrosine kinase –> lack of inhibition of chondrocyte prolif
- multiple 2ndart centers of ossification in epiphysis
Osteochondrosis
- Delay of endochondral ossification
- -> retention of growth cartilage OR articular epiphyseal cartilage necrosis
- Always vascular insult
- Other factors contribute:
- rapid growth
- Co deficient
- trauma
- all species –in long bones!
- Cattle: distal talus
Pathogenesis of Osteochondrosis
Ischemic necrosis AEC around necrotic vessels (osteochondrosis LATENT) –Trabeculae normal
–> failure of endochondral ossification
–> retention of necrotic epiphyseal cartilage (osteochondrosis MANIFESTA)–myelofibrosis & modeling
–> traumatic clefting through the area of necrosis (osteochondrosis DISSECANS) or replacement of necrotic cartilage by subchondral bone
Osteochondrosis manifesta
retention of necrotic epiphyseal cartilage
Osteochondrosis dissecans
Cleft formation of necrotic cartilage in Young pigs
- -> separation of overlying articular cartilage
- -> detachment –> JOINT MOUSE –> degenerative joint dz
Articular Epiphyseal cartilage:
- fibroplasia
- neovascularized
- remodeled
Trabecular bone:
-Fibrosis & woven bone at base of flap
Epiphysiolysis
Epiphysis / Metaphysis separate due to abnormal physis
-Trabeculae –> myelofibrosis, woven bone & hemorrhage
Common locations:
Pigs –Femoral head, ischial tuberosity
Dog –Anconeal process
Cats –Femoral head
Cervical Stenotic Myelopathy
aka Wobblers
Osteochondrosis of cervical vertebrae –> narrowed spinal canal –> spinal cord compression –> neuro dz in HORSE / Giant breed DOGS
- Cervical Vertebral Instability
- Dynamic stenosis
- C3-4 & C4-5
- 6-15 mo Horses
- Cervical Static Stenosis
- C5-6 & C6-7
- 1-4y Horses
Osteoporosis ( causes )
Increased O-clasts & decreased O-blasts –> Reduced bone density –> fractures
(thin trabeculae and cortical bone)
Cause:
- Ca deficiency (hyper-PTH)
- starvation
- physically inactive
- hypogonadism
- chronic glucocorticoid
- menopause
Estrogen effects on bone
Anabolic
- Increases TGF beta
- Inhibits TGF alpha, IL1, IL6 –> bone formation
Rickets
what is it called in adults?
Osteomalacia
-failure to mineralize bone
Cause:
- Vit D/ Phos deficiency
- Chronic renal dz
- Fluorosis
- Diffuse irregular thickening of growth plate
- Unmineralized Osteoid in trabeculae and cortex
-sometimes in conjunction w/ Fibrous Osteodystrophy
Fibrous Osteodystrophy
Extensive O-clast resorption replaced by primitive fibro-osseous tissue
Trabeculae - replaced by woven bone & Fibrous CT - numerous Oclasts Cortical -Resorption -Fibrosis
Cause:
- Hyperparathyroidsm (nutritional / renal)
- bran (horse)
- cereal grain (pig)
- all meat rations (dog)
