Exam 2 Flashcards
1
Q
osteoid
A
bone matrix of type I collagen & ground substance (proteoglycans)
produces scaffolding/strength of bone
2
Q
tension on bone results in…
A
bone resorption
3
Q
inactivity of bone results in…
A
bone resorption
4
Q
mechanical load & compression on bone results in…
A
bone deposition
5
Q
3 pathologies of infectious osteomyelitis
A
trauma
local extension from adjacent infected site (e.g. lumpy jaw)
hematogenous (septic)
6
Q
why are young livestock at increased risk of septicemia –> physitis or osteomyelitis
A
decreased or failed passive transfer
7
Q
Common aerobic etiologies for infectious osteomyelitis
A
Brucella
E. coli
Staph
Strep
8
Q
Common anaerobic etiologies for infectious osteomyelitis
A
Salmonella (facultative)
Clostridium
Actinomyces
9
Q
Common fungal etiologies for infectious osteomyelitis
A
Coccidioides immitis
Blastomyces dermatitidis
10
Q
lameness or paresis, recumbency
fever
A
infectious osteomyelitis
11
Q
Sequestrum & involucrum
A
trauma/hypoxia –> bone necrosis –> foreign body reaction, lytic/exudate pocket
12
Q
2 pathologies of non-infectious osteomyelitis
A
Panosteitis Metaphyseal osteopathy (or hypertrophic osteodystrophy)
13
Q
Signalment for panosteitis
A
young (5-18 mo) large breed male dogs
German shep, goldens
14
Q
Recurrent shifting leg lameness (pain on palpation) - self limiting
anorexia, mild lethargy, +/- fever
A
Panosteitis
15
Q
What lesions are caused by Panosteitis?
A
medullary fibrosis & ossification (looks enlarged on rads), vascular congestion/edema
16
Q
Metaphyseal osteopathy (or hypertrophic osteodystrophy) causes what lesions
A
- metaphyseal (NOT physeal) vascular & trabecular necrosis
- suppurative inflammation
- metaphyseal & periosteal bone proliferation
17
Q
Signalment for HOD
A
younger (2-8 mo) large and giant breed dogs
Danes, Weimaraner’s, Boxers, German shep
18
Q
Suspected causes of HOD
A
idiopathic
Diet - excess Ca, vitamins, calories, hypovitaminosis C
Genetic
Infectious - canine distemper vacc, E. coli sepsis
19
Q
Severe, progressive lameness
lethargy, anorexia, fever
swollen painful metaphyses of distal radius, ulna, tibia
A
HOD
20
Q
Pathognomonic sign of HOD
A
“double physis” on rad - reactive fare trying to stabilize metaphysis
21
Q
What causes metabolic bone disease
A
calcium phosphorus imbalance
22
Q
4 types of metabolic bone disease (all d/t Ca/P imbalance)
A
Osteoporosis
Osteomalacia
Rickets
Fibrous osteodystrophy
23
Q
What is osteoporosis?
A
- Not enough normal bone
- decreased production of normal bone or excess bone removal
- reversible
24
Q
Causes of osteoporosis
A
- physical inactivity, disuse atrophy
- starvation (Ca deficiency = increased PTH)
- decreased estrogen
- glucocorticoids
25
Pathological fracture, bone deformities
| Cortical thining, increased porosity of bone
oseoporosis
26
What is osteomalacia
defective mineralization of osteoid/cartilage - can lay down Ca & P on osteoid
27
What causes osteomalacia
```
vit d deficiency (decreased Ca, P absorption)
Phosphorus deficiency (or Ca or both)
```
28
Pathological fractures, bone deformities
Extensive matrix of non-mineralized osteoid
cortical and trabecular thinning (soft bone)
osteomalacia
29
What is rickets
defective mineralization of osteoid specifically in the physis (how differs from osteomalacia)
happens in juveniles only
30
Causes of rickets
```
Vit D (rarely hereditary) or P deficiency
Ca deficiency or excess (uncommon)
```
31
2 types of hereditary vit D deficiency
type I - enz deficiency (makes active form of vit D)
| type II - vit D receptor defect
32
thick, wide irregular physes, metaphyseal flare, enlarged joints, valgus/varus deformities, rachitic rosary
rickets
33
Fibrous osteodystrophy
juveniles, rarely adults
| High PTH --> excess Ca release from bone --> replacement fibrosis - soft spongy bones
34
Causes of fibrous osteodystrophy
```
Primary hyperparathyroidism (rare)
Secondary " " (renal dz or nutritional issue)
```
35
How does renal dz cause secondary hyperparathyroidism (thus, fibrous osteodystrophy)
Decreased excretion of P = high P, low Ca = increased PTH secretion = more Ca mobilized from bone
36
How does nutrition cause secondary hyperparathyroidism (thus, fibrous osteodystrophy)
high P, low Ca, low Vit D = increased PTH secretion = more Ca mobilized from bone
e.g. carn on meat diet, Pig/EQ on grain/bran diets, lack of UVB in reptiles
37
lameness, pathological fracture
"rubber jaw" or twisted maxilla
swollen metaphyses (but physis normal) valgus/varus deformities
fibrous osteodystrophy
38
Osteochondrodysplasia
abnormal endochondrial ossification --> defective cartilage development --> (disproportionate) dwarf stature or uncontrolled growth
39
What causes osteochondrodysplasia
spontaneous or heritable of mutation FGFR3
40
Osteopetrosis/Stone bone
osteoclast deficiency/dysfunc --> excess trabecular bone, failed osteoclastic remodeling --> cavity filled w/ cancellous bone, not spongy bone & marrow
41
Causes of osteopetrosis
spontaneous congenital defect
hereditary - angus, paso fino
infectious: BVDV, FeLV, CDV
42
lameness, neuro disease d/t flattened calvarium, tongue hangs out, pathological fracture & deformities, pancytopenia
osteopetrosis
43
Osteogenesis imperfecta/Brittle bone dz
multiple genetic disorders --> failure to produce & cross link type I collagen, decreased osteonectin --> bone deformities
Calves, lambs, puppies
44
bone fractures/deformities, tendon & ligament ruptures, weak enamel & sclera
osteogenesis imperfecta
45
Hypertrophic osteopathy pathogenesis
Suspect vagal stimulation --> increased perfusion to periosteum --> blood pools --> peripheral hypoxia/reaction --> periosteal woven bone hypertrophy (just cortex)
46
What is hypertrophic osteopathy comonly associated with?
Thoracic mass
Heartworm dz
Endocarditis
NEoplasia - urinary rhabdomyosarcoma, EQ ovarian tumors
47
Swollen but firm (not edematous) limbs, lameness
Hypertrophic osteopathy
48
Aseptic necrosis of the femoral head / Legg-Calve’-Perthes Dz pathogenesis
Loss of perfusion --> ischemic necrosis of femoral head --> subchondral bone collapse & fibrosis --> progressive hip joint pain
49
Who gets Aseptic necrosis of the femoral head
young (4-12 mo) small terriers like yorkies, jack russels
50
What is the most common primary bone tumor in domestics?
Osteosarcoma
51
Osteosarcoma
malignant mesenchymal tumor of osteoblasts
| produces osteoid
52
Risk factors for osteosarcoma
Size – dogs >80 lb (St. Bernards, Danes, German shep)
| Age – dogs > 7.5 yrs, cats >10/5 yrs
53
Osteosarcoma locations
Dog - away from elbow, toward knee
| Uncommonly cat anywhere, Rum/EQ flatbones of skull
54
Osteosarcoma behavior
Osteolytic - destroys cortical bone, stimulates reactive woven bone & inflamm around site
Highly invasive but doesn't cross joints/articular surfaces
often metastasizes to lungs early
55
Chrondrosarcoma
malignant tumor of cartilage, usually affecting flat bones (nasal cavity), appendicular, joints, soft tissue
56
Chrondrosarcoma behavior
osteolytic, invasive/space occupying
| develops slower, metastasizes later (better for treatment)
57
Fibrosarcoma
primary malignant tumor of fibroblasts
Often in periosteum/medulla of any flat/long bone
space occupying, lytic, destructive
58
Osteoma
benign tumor of osteoblasts/cytes
Affects cortex, usually on flat bones, distal limbs
Rostral mandible in juv rum/EQ - eating issue
59
Multilobular osteochondrosarcoma (MLO)
benign or malignant tumor of organized cartilage, bone and fibrocytes
space occupying - often calvarium/flat bones
see neuro dz or difficulty eating
60
What is hyaline/articular cartilage composed of?
type II collagen
chrondrocytes
proteoglycans
water
61
How does hyaline cartilage get it's nutrition & oxygen supply?
subchondral bone
| synovial fluid
62
How does articular cartilage respond to injury?
poor healing capacity
superficial lesion = no healing, no progression
deep lesions = granulation, fibrocartilage
Fibrillation, eburnation
63
Fibrillation
cartilage condenses/clumps, starts to fray
64
Eburnation
subchondral bone exposed through cartilage
65
How does synovium respond to injury?
inflammation
villous hyperplasia of synoviocytes
Pannus (fibroplasia over areas of eburnation)
66
How does synovial fluid respond to injury?
```
fluid volume increases
Viscosity changes (increased = fibrin, Ig presence, decreased = hyaluronic acid & proteoglucan loss)
```
67
Periarticular lesions you may see with joint injury
Osteophytes
Enthesophytes
Joint mice
68
What causes degenerative joint disease (thus, osteoarthritis)
chronic instability
abnormal/altered cartilage
abnormal/altered subchondral bone
69
Mechanisms that cause infectious OA
- direct inoculation of joint
| - hematogenous/septic spread
70
Causes of hematogenous spread --> OA
failure of passive transfer
| Mycoplasma bovis or hyosynoviae, Strep, Staph, E.coli
71
Immune-mediated polyarthritis (IMPA)
Type III hypersensitivity --> chronic joint inflamm, arthritis
Idiopathic, hereditary, secondary (SLE, rhematoid, neoplasia)
72
Who is prone to IMPA
dogs - Akitas, beagles, boxers
73
fever, lethargy, anorexia
joint swelling, shifting leg lameness, stilted painful gait
+/- back or neck pain
IMPA
74
Osteochondrosis pathogenesis
Failed endochondrial ossification of the epiphysis --> unmineralized epiphyseal cartilage --> focal areas of abnormal thickening of cartilage
75
What can osteochondrosis progress to?
Osteochondrosis dessicans
thick cartilage --> hypoxia --> necrosis & fragmentation of cartilage --> subchondral bone exposed, weakened --> subchondral cyst --> cavitating defect
76
Risk factors for osteochondrosis
genetics - rapid growers
nutrition - high calories, Ca, protein, vitamins/minerals or low Cu
Management - mechanical stress, exercise etc.
77
Who commonly gets osteochondrosis
pigs, chickens, large breed dogs, warmbloods, throughbreds
78
Common sites of osteochondrosis
main appendicular joints: stifle, shoulder, fetlock, tarsus
79
Lamenss, pain, decreased performance, decreased weight gain
osteochondrosis
80
Who is especially prone to subchondral bone cysts & fractures
horses
81
Synovial sarcoma
malignant neoplasm of synovial cells
large breed middle age dogs
often stifle or weight bearing appendicular joints
highly invasive into surrounding area (unlike osteosarcomas), many metastasize to lungs
amputate
82
Periarticular histiocytic sarcoma
malignany neosplasm of synovial DC's
large breed middle age dogs - bernese mountain dogs
invasive into soft tissue, osteolytic
majority matastasize & early
83
Job of intervertebral disks
unite vertebrae
limit movement at intervertebral joint
distribute mechanical forces
84
Job of nucleus pulposus
absorb shock, help w/ felxibility
85
Job of annulus fibrosus
handles compression, equalizes load
86
Job of intercaptial ligaments
stabilize ribs, vertebrae
| Only exists between T2-T10, not cervical or lumbar regions (need more flexibility)
