Bones Pathology

Question 1

What are the different stages of fracture repair?

Answer 1

a. Hematoma
b. Fibrocartilaginous callus (soft callus
c. Bony callus
d. Bony remodeling

Question 2

What is lamellar bone?

Answer 2

mature with well-organized collagen bundles that form compact/ cortical bone & cancellous/spongy bone.

Question 3

What is woven bone?

Answer 3

occurs in developing fetus and in response to injury. It does it remodeled and replaced by lamellar bone.

Question 4

What are consequences of growth plate damage and/or growth plate fracture?

Answer 4

cessation of bone growth & angular limb deformity ( most commonly occurs in distal radial physis)

Question 5

What is the genetic mutation responsible for spider lamb syndrome?

Answer 5

FGF Receptor 3

Question 6

Osteogenesis imperfecta pathogenesis?

Answer 6

defective type 1 collagen leads to reduced bone mass, bone fragility & increased fracture frequency.

Question 7

Osteogenesis imperfecta associated signs?

Answer 7

bowing of limbs, reduced growth, joint laxity, opalescent, fragile teeth & blue sclera

Question 8

What 2 mechanisms for osteoperosis?

Answer 8

dysfunctional osteoclast or decreased osteoclast numbers

Question 9

What are gross changes associated with CMO?

What dog breeds are usually affected?

Answer 9

affect mandible, occipital & temporal bones & can result in ankylosis (fusion of temporal & mandibular joint).
- West highland terriers & scottish terrier

Question 10

What is osteroperosis?

Answer 10

reduced bone mass/density but normal mineralization

• term used when clinical
• subclinical called osteopenia

Question 11

What are the possible causes of osteroperosis?

Answer 11

Protein calorie malnutrition, dietary calcium deficiency, reduced physical activity, hyperglucocorticoidism & decreased E2 levels (human)

Question 12

What causes ricketts or osteomalacia?

Answer 12

Vitamin D or Phosphorus deficiency

Question 13

What is osteomalacia?

Answer 13

occur in adults with no lesions at growth cartilage

Question 14

What is ricketts?

Answer 14

disease of young, growing skeleton d/t abnormal endochondral ossification at growth plates & defective bone formation

Question 15

What is underlying pathogenesis for fibrous osteodystrophy?

Answer 15

persistent elevation of plasma PTH

caused by primary hyperparathyroidism, nutritional hyperparathyroidism, renal secondary hyperparathyroidism, hypercalcemia of malignancy

Question 16

fibrous osteodystrophy associated lesions?

Answer 16

bilateral enlargement of skull bone (rubber jaw), cortical bone & marrow cavity filled with fibrous tissue, loose teeth w/ increased risk of fractures/ligament avulsions.

Question 17

What animal species that are susceptible to Vitamin C deficiency (scurvy)?

Answer 17

Primates, guinea pigs & some bats

Question 18

What effect does lead toxicosis have on bone?

Answer 18

toxic to osteoclast and causes a band of sclerotic bone at metaphysis in growing bone (lead line) with persistent mineralized cartilage.

Question 19

What bone changes occur with vitamin A tox?

Answer 19

osteophyte formation & periosteal bone formation (chronic)

• source: liver in diet

Question 20

Sources of Vitamin D tox

Answer 20

Vit D plant ingestion, excess vit D in diet, cholecalciferol rodenticide

Question 21

What are the routes of bacterial infection?

Answer 21

hematogenous, local extension & implantation (penetrating trauma/ open fx)

Question 22

why does hematogenous osteomyelitis often localize at sites of endochondral ossification?

Answer 22

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

Question 23

What are possible sequelae to vertebral osteomyelitis?

Answer 23

i. pathologic fx & vertebral body collapse
ii. supportive exudate & bone fragments into spinal cord (cord compression)
iii. acute onset of neurologic signs (paresis/paralysis)

Question 24

What is the causative agent for lumpy jaw?

Answer 24

Actinomyces bovis

Question 25

What lesions are associated with lumpy jaw?

Answer 25

marked pyogranulomatous inflammatory response, marked periosteal woven bone proliferation, granulation tissue deposition & loss teeth

Question 26

What are the bacterial agents associated with atrophic rhinitis?

Answer 26

Pasturella multocida & Bordetella bronchiseptica

Question 27

Atrophic rhinitis sequela

Answer 27

toxin inhibits osteoblast & stimulates osteoclast, so get nasal turbinate bone destruction

Question 28

What are the fungal agents that likely induce osteomyelitis:

Answer 28

Coccidioides immitis, Blastomyces dermatitidis & Cryptococcus sp.

Question 29

Viral agents that can induce metaphyseal sclerosis:

Answer 29

BVDV, classical swine fever virus, border disease virus, canine distemper virus

Question 30

Hypertrophic osteodystrophy is…

Answer 30

characterized by periosteal new bone formation on long bones (especially distal extremities)

Question 31

HOD signalment & CS

Answer 31

Signalment: young growing dogs, esp. large & giant breeds ( Great Danes, Boxers & GSD)

CS: fever, malaise, lameness & swelling/pain of long bone

Question 32

HOD rad changes?

Answer 32

double physeal line

Question 33

Panosteitis signalment & CS

Answer 33

Signalment: large/ giant dogs (5-12 mo)
CS: shifting lameness ( mild/severe) usually forelimb

Question 34

Associated rad changes in panosteitis

Answer 34

patchy area of radiodensity of diaphysis (area of nutrient foramen)

Question 35

Legg- Calve Perthes DZ- signament

Answer 35

small/ toy dog breeds (4-11 mo) esp. mini poodles, yorkies, west highland terriers

Question 36

What are osteochondromas?

Answer 36

Benign, cartilage tumor like exostosis (arise from endochondral bone surface)
* they can undergo malignant transformation!

Question 37

fibrosarcoma types are

Answer 37

phenotypic low grade but biologically high grade!