Bones Pathology Flashcards
What are the different stages of fracture repair?
a. Hematoma
b. Fibrocartilaginous callus (soft callus
c. Bony callus
d. Bony remodeling
What is lamellar bone?
mature with well-organized collagen bundles that form compact/ cortical bone & cancellous/spongy bone.
What is woven bone?
occurs in developing fetus and in response to injury. It does it remodeled and replaced by lamellar bone.
What are consequences of growth plate damage and/or growth plate fracture?
cessation of bone growth & angular limb deformity ( most commonly occurs in distal radial physis)
What is the genetic mutation responsible for spider lamb syndrome?
FGF Receptor 3
Osteogenesis imperfecta pathogenesis?
defective type 1 collagen leads to reduced bone mass, bone fragility & increased fracture frequency.
Osteogenesis imperfecta associated signs?
bowing of limbs, reduced growth, joint laxity, opalescent, fragile teeth & blue sclera
What 2 mechanisms for osteoperosis?
dysfunctional osteoclast or decreased osteoclast numbers
What are gross changes associated with CMO?
What dog breeds are usually affected?
affect mandible, occipital & temporal bones & can result in ankylosis (fusion of temporal & mandibular joint).
- West highland terriers & scottish terrier
What is osteroperosis?
reduced bone mass/density but normal mineralization
- term used when clinical
- subclinical called osteopenia
What are the possible causes of osteroperosis?
Protein calorie malnutrition, dietary calcium deficiency, reduced physical activity, hyperglucocorticoidism & decreased E2 levels (human)
What causes ricketts or osteomalacia?
Vitamin D or Phosphorus deficiency
What is osteomalacia?
occur in adults with no lesions at growth cartilage
What is ricketts?
disease of young, growing skeleton d/t abnormal endochondral ossification at growth plates & defective bone formation
What is underlying pathogenesis for fibrous osteodystrophy?
persistent elevation of plasma PTH
caused by primary hyperparathyroidism, nutritional hyperparathyroidism, renal secondary hyperparathyroidism, hypercalcemia of malignancy
fibrous osteodystrophy associated lesions?
bilateral enlargement of skull bone (rubber jaw), cortical bone & marrow cavity filled with fibrous tissue, loose teeth w/ increased risk of fractures/ligament avulsions.
What animal species that are susceptible to Vitamin C deficiency (scurvy)?
Primates, guinea pigs & some bats
What effect does lead toxicosis have on bone?
toxic to osteoclast and causes a band of sclerotic bone at metaphysis in growing bone (lead line) with persistent mineralized cartilage.
What bone changes occur with vitamin A tox?
osteophyte formation & periosteal bone formation (chronic)
- source: liver in diet
Sources of Vitamin D tox
Vit D plant ingestion, excess vit D in diet, cholecalciferol rodenticide
What are the routes of bacterial infection?
hematogenous, local extension & implantation (penetrating trauma/ open fx)
why does hematogenous osteomyelitis often localize at sites of endochondral ossification?
i. metaphyses & epiphyses of long bone & vertebral bodies
ii. loops of capillaries invading mineralized cartilage
iii. capillaries are fenestrated
iv. blood flow is sluggish in this area
What are possible sequelae to vertebral osteomyelitis?
i. pathologic fx & vertebral body collapse
ii. supportive exudate & bone fragments into spinal cord (cord compression)
iii. acute onset of neurologic signs (paresis/paralysis)
What is the causative agent for lumpy jaw?
Actinomyces bovis
What lesions are associated with lumpy jaw?
marked pyogranulomatous inflammatory response, marked periosteal woven bone proliferation, granulation tissue deposition & loss teeth
What are the bacterial agents associated with atrophic rhinitis?
Pasturella multocida & Bordetella bronchiseptica
Atrophic rhinitis sequela
toxin inhibits osteoblast & stimulates osteoclast, so get nasal turbinate bone destruction
What are the fungal agents that likely induce osteomyelitis:
Coccidioides immitis, Blastomyces dermatitidis & Cryptococcus sp.
Viral agents that can induce metaphyseal sclerosis:
BVDV, classical swine fever virus, border disease virus, canine distemper virus
Hypertrophic osteodystrophy is…
characterized by periosteal new bone formation on long bones (especially distal extremities)
HOD signalment & CS
Signalment: young growing dogs, esp. large & giant breeds ( Great Danes, Boxers & GSD)
CS: fever, malaise, lameness & swelling/pain of long bone
HOD rad changes?
double physeal line
Panosteitis signalment & CS
Signalment: large/ giant dogs (5-12 mo)
CS: shifting lameness ( mild/severe) usually forelimb
Associated rad changes in panosteitis
patchy area of radiodensity of diaphysis (area of nutrient foramen)
Legg- Calve Perthes DZ- signament
small/ toy dog breeds (4-11 mo) esp. mini poodles, yorkies, west highland terriers
What are osteochondromas?
Benign, cartilage tumor like exostosis (arise from endochondral bone surface)
* they can undergo malignant transformation!
fibrosarcoma types are
phenotypic low grade but biologically high grade!
