Pathology bone Flashcards
What is Amelia?
Genetic abnormality in which animal is born without limbs & there is no underlying cause
What is polydactyly?
Genetic abnormality in which there are to many toes and there is no underlying cause
What is osteopetrosis?
inherited defect in osteoclastic resorption resulting in too dense medullary bone and to thin cortical bone
What are some of the causes for osteopetrosis?
Bovine viral diarrhea virus (BVDV)
Feline leukemia
Avian leucosis virus
What is craniomandibular osteopathy?
“Lion Jaw”
Bilateral symmetrical thickening of mandible, occipital, temporal bones, +/- tympanic bullaw
What is the lesion associated with craniomandibular osteopathy and who does it normally affect?
proliferation of bone
Seen in dogs less than 1 year of age and may spontaneously regress
What is craniomandibular osteopathy associated with in Irish setters? Terriers?
Canine leukocyte adhesion disease
Autosomal recessive gene
What is chondrodysplasia (chondrodystrophy)
associated with inheritable defect in growth plate cartilage (at the physis & articular epiphyseal cartilage complex) resulting in premature growth plate closure leading to shortened long bones that are normal in width
What gene mutation is associated with chondrodysplasia (chondrodystrophy) and what is the gene supposed to do? What happens when there is a mutation
FGFR3 (fibroblast growth factor receptor) gene that regulates cartilage growth. With the mutation it either inhibits or increases growth plate cartilage production
What is Spider lamb chondrodysplasia?
Excessive proliferation of growth cartilage that is very disorganized
What is Osteochondrosis?
Failure or delay of endochondral ossification in the metaphyseal growth plate, epiphyseal cartilage
What is the mechanism of osteochondrosis?
Multifactoral
- Genetics
- Rapid growth
- no vascular invasion then the cartilage fails to mineralize
- traumatic injury
What is pathogenesis of Osteochondrosis?
1) vascular necrosis which causes ischemic damage to the cartilage
2) as the growth front approaches the primary spongyosa zone of mineralization those spicules of cartilage will not by mineralized
3) We get detained cores of unmineralized cartilage
4) The retained core of unmineralized cartilage is susceptible to traumatic damage & it will flap off
What stage is osteonecrosis latency?
When osteochondrosis only produces a microscopic lesion that you can’t see with the naked eye. (Pathogenesis steps 1-2)
What stage is osteoporosis manifesto?
Once the lesion gets to the mineralization front & produces a visible lesion, which is retained core of cartilage (pathogenesis step 3).
What stage is osteochondrosis dissecans?
When unmineralized cartilage is susceptible to traumatic damage & it flaps off (Pathogenesis step 4)
What is cervical vertebral stenotic myelopathy?
Wobblers Syndrome
An abnormal development of the cervical vertebrae which leads to either static or dynamic spinal cord compression
What is Static spinal cord compression and what vertebra are typically affected?
Compressed all the time no matter what position the horse is in
C5-C6, C6-C-7
What is Dynamic spinal cord compression and what vertebra are typically affected?
Compression changes during flexion vs. extension
C3-C4, C4-C5
What is Cervical vertebral stenotic myelopathy associated with
osteoporosis of the cervical facets (the articulating portion of the vertebral bodies)
What is osteoporosis?
Reduction in bone density that leads to a fracture
What is the difference between osteoporosis & osteopenia.
Osteoporosis is the reduction of bone density that leads to a fracture while osteopenia is a reduction in bone mass without clinical disease
What are some causes of Osteoporosis?
Malnutrition (not enough calcium & phosphorus)
Immobilization (disuse osteoporosis)
Dietary calcium deficiency
Senile osteoporosis
Excess glucocorticoids
What is Fibrous osteodystrophy?
Excessive resorption of bone due to PTH & replaced with fibrous connective tissue
What is the pathogenesis of fibrous osteodystrophy?
1) Increased PTH (HYPERTHYROIDISM)
2) PTH binds to osteoblasts
3) They release from surface of bone & increase osteoclast resorption
4) Increases fibrous proliferation
What else can cause the pathogenesis of fibrous osteodystrophy? What is it?
PTHrP is structurally similar to PTH and is produced in neoplastic cells of AGASACA & Lymphoma and causes para neoplastic hypercalcemia
What are the characteristics of Rickets?
Growing animals
Effects bone & growth plate cartilage
Failure of endochondral ossification (results in thickened growth plates)
What are the characteristics of Osteomalacia?
Adults
Failure of mineralization
Impairs bone remodeling (results in brittle bones that may fracture)
What is the most common cause of Rickets and Osteomalacia?
Vitamin D or phosphorus deficiency
What is hypertrophic osteodystrophy? What causes it?
Suppurative osteomyelitis of the metaphysis of long bones just below the growth plate & infraction
Cause unknown
What is an infractions?
fracture of medullary bone without fracture of cortical bone
What is Hypertrophic osteopathy? What does it occur secondary to
Bilateral progressive periosteal new bone
Occurs secondary to intrathoracic neoplasms or inflammation (pneumonia)
What are primary neoplasms of bone?
- Osteosarcoma
- Chondrosarcoma
- Fibrosarcoma
- Osteoma
- Chondroma
What are secondary neoplasms of bone?
Mammary, prostate, thyroid, ovarian, pulmonary carcinomas
Lymphoma
What is an Chondrosarcoma?
malignant tumor of cartilage
What is a Fibrosarcoma?
fibroblasts in the medullary cavity malignant
What is an Osteoma?
benign tumors of bone
What is a Chondroma?
benign tumors of cartilage
What is an Osteosarcoma?
Malignant tumor of bone
What are the defining characteristics of osteosarcoma?
Effects large breeds
Primarily in the primarily in the appendicular skeleton more than the axial skeleton
Don’t cross joints
What is the primary site of metastasis for osteosarcoma?
Lungs
What specific anatomic sites are osteosarcoma usually found?
Distal femur
Proximal tibia
What is multilobular osteosarcoma?
Arise from flat bone
Locally invasive & destructive
Lower metastatic potential than normal osteosarcoma
What will osteosarcoma insight?
non-neoplastic periosteal proliferation
