Vet Path B 250-215 Bone Abnormal Development

Front 1

Skeletal dysplasia

Back 1

Abnormal development of bone

Front 2

Skeletal dysplasia
- 2 types

Back 2

Generalised dysplasia

Localised dysplasia

Front 3

Generalised dysplasias (5 types)

Back 3

chondrodysplasia
osteogenesis imperfecta
osteopetrosis
hyperostosis
osteochondromatosis

Hint 3

Ch______
Osteo___ ____
Osteo____
Hyper____
Osteochondro_____

Front 4

Chrondrodysplasia
- definition
- bones most affected
- aka

Back 4

Underlying defect in cartilage formation

Affects bones formed by endochondrial ossification (long bones, vertebra, basocranial)

Disporportionate dwarfism

Front 5

Examples of chondrodysplasia in cattle

Back 5

Front 6

Examples of chondrodysplasia in sheep

Back 6

Note: spider lamb exception with long limbs

Front 7

Examples of chondrodysplasia in dogs

Back 7

Inherited defect in Alaskan Malamutes, English pointer, Scottish Deerhound & others

Front 8

Why do the tongues stick out in chrondrodysplastic animals?

Back 8

Soft tissue growth is not affected

Front 9

Features of long bones in most chondrodysplasias

Back 9

Epiphyses are enlarged and mushroom shaped dt
arrested interstitial growth along with normal appositional growth

Front 10

Varus
Valgus

Back 10

Valgus is knock-kneed

Front 11

Osteodysplasia

Back 11

Abnormal development of bone

Front 12

Osteogenesis imperfecta
- cause
- pathogenesis

Back 12

Inherited defect in Type I collagen
Autosomal dominant in some breeds

Abnormal bone shape
Susceptibility to fractures

Front 13

Osteogenesis imperfecta

Cattle breed most affected

Back 13

Front 14

Osteopetrosis
- cause
- pathogenesis

Back 14

Defective osteoclast function

Poor remodelling, increased fragility

mostly a LETHAL trait

Front 15

Osteopetrosis
- unusual features of long bones

Back 15

Osteoclast defect - Medullary cavity filled with coarsely woven bone and cartilage - Thin diaphyseal cortices

Front 16

Congenital hyperostosis
- affects
- pathogenesis

Back 16

Inherited disorder in Landrace pigs

Thick limbs dt

subperiosteal fibrosis and new bone deposition

possibly due to vascular drainage anomaly

Front 17

Exostosis

Back 17

Benign new growth projecting from bone surface and characteristically capped by cartilage

Front 18

Osteochondromatosis

Back 18

Inherited condition in humans, dogs & horses

Single or multiple tumour-like exostoses

Front 19

3 main generalised dysplasia
- brief cause

Back 19

Chondrodysplasia: defect in cartilage formation

Osteogenesis imperfecta: defect in Type I collagen

Osteopetrosis: defect in osteoclast function

Front 20

Localised skeletal dysplasia
- 4 main sites

Back 20

Limbs
Skull
Vertebrae
Cervical vertebrae

Front 21

What's this?

Back 21

Syndactylyl
Polydactyly

Front 22

What's this?
What's the opposite called?

Back 22

Brachygnathia inferior
opp = brachygnathia superior

Front 23

Scoliosis

Kyphosis

Back 23

Scoliosis: lateral deviation of the spine

Kyphosis: dorsal deviation of the spine (humpbacked)

Front 24

Spina bifida
- most common in which animal

Back 24

Defective closure of dorsal vertebral laminae in a segment of the vertebral column (dt defective neural tube closure)

Manx cats (lethal)

Front 25

"Wobbler syndrome"

- correct name

Back 25

Cervical vertebral stenotic myelopathy

Hint 25

Cevical vertebral s____ m_____

Front 26

"Wobbler syndrome"
- animals most affected

Back 26

Horses & large breed dogs (esp Great Danes, Dobermans)

Front 27

"Wobbler syndrome"
- 2 forms

Back 27

Cervical vertebral instability
- cord damage is due to abnormal movement of neighbouring vertebra

Cervical static stenosis
- static lesion, present in all neck postures

Front 28

"Wobbler syndrome"
- pathogenesis in horses

Back 28

Cervical instability most common

- high energy diets fed to genetically predisposed yearlings

- C3 - C5 often

- progressive hind limb ataxia dt compression or stretching of cord

Front 29

Transection of cervical spinal cord from horse

Back 29

Wobbler Syndrome

Cervical vertebral stenotic myelopathy

"cervical vertebral instability" form

Front 30

2 genetic diseases INdirectly affecting the skeleton

Back 30

Lysosomal storage diseases
- mucopolysaccharidoses
- GMI gangliosidosis

Congenital erythropoietic porphyria

Front 31

Genetic diseases INdirectly affecting the skeleton

- Systems most affected

Back 31

CNS principally affected

Also skeletal deformities

Front 32

Samples from cattle
What condition is this showing?

Back 32

Congenital erythropoietic porphyria

Front 33

Congenital erythropoietic porphyria
- pathogenesis in cattle

Back 33

Inherited enzyme deficiency leading to accumulation of porphyrins in blood, bone, other tissues

Red brown discolouration of teeth and bones
Teeth & bones -> cherry red with UV exposure

Mild-mod anaemia
Photosensitisation if deposited in skin

Front 34

What are "acorn calves"?

What is the likely cause?

Back 34

Acorn calves have skeletal abnormalities
- disporportionate dwarfism, joint laxity
- sometimes vargus, valgus
- sometimes brachygnathia superior

Possible dt in utero exposure to a MYCOTOXIN (acorns are blameless!)

Front 35

What's this?

Back 35

Valgus (knock knees) Varus (bow legs)

Front 36

Viruses affecting bone cell activity

Back 36

BVDV (a pestivirus)
Classical swine fever (a pestivirus)
Canine distemper virus
FeHV

- possible dt viral destruction of osteoclasts (same cell lineage as monocytes/macrophages)

Front 37

What's the arrow pointing to?

Back 37

"Growth arrest lattices"
dt impaired remodelling due to reduced osteoclast activity

Front 38

What's the difference between "growth arrest lattices" and "growth arrest lines"

Back 38

Growth arrest lattices are primary trabeculae that do not remodel dt paucity of osteoclasts - may resolve once antigen removed (eg canine distemper)

Growth arrest lines are due to reduced bone growth often dt malnutrition or starvation. It is a horizontal plate of bone, signaling interrupted growth.

Front 39

What's this showing?

Back 39

Malnutrition or starvation retard longitudinal bone growth, thin the physis and form a bony plate in the metaphysis.

Resumption of growth following correction forms a growth arrest line (radiotranslucent)

Front 40

What's this?
What's it due to?

Back 40

Cyclops lamb
Plant Verratrum californicum toxicity
- effects depend on stage of pregnancy exposed

Front 41

Inflammatory conditions of bone (3)

Back 41

Periostitis

Osteitis

Osteomyelitis

Front 42

Periostitis

Back 42

Inflammation of bone with the periosteum involved

Front 43

Osteitis

Back 43

General term for inflammation of bone, rarely used.

Front 44

Osteomyelitis

Back 44

Inflammation of bone with the medullary cavity involved

Front 45

Non-infectious inflammation of bone
- how?

Back 45

Single episode or repeated trauma

thus periostitis bc periosteum is involved

Front 46

Possible routes of infection of bone (3)`

Back 46

Haematogenous (embolic during septicaemia)

Direct implantation (penetrating trauma)

Local extension (from infected adjacent structure)

Front 47

Why are growth plates vulnerable to haematogenous infection?

Back 47

Fenestrated capillary loops (bendy bits slow down) in the metaphysis

Front 48

4 steps in bone lesions dt bacterial infection (in detail)

Back 48

1. Exudate + oedema > incr intramedullary pressure > ischaemia

2. Vascular stasis, infarction, toxic products (leukocytes, dying cells, bacterial toxins) > bone necrosis

3. Phagocytosis & osteoclastic resorption of necrotic bone, and/or

4. Necrotic bone remains as a sequestrum

Front 49

Sequestrum & Involucrum

Back 49

Front 50

3 sequelae to osteomyelitis
(not including resolution)

Back 50

Pathologic fractures

Growth disturbances, esp if physes involved

Damage to articular cartilage & extension into joints

Front 51

Calf vertebral column.
What's this? Likely cause?

Back 51

Vertebral ostemomyelitis and necrosis
Actinomyces pyogenes

Front 52

Bovine vertebrae. Causative agent?

Back 52

Hydatid cyst

Front 53

Bovine mandible
Common name Correct name Causative agent

Back 53

Lumpy jaw
Chronic pyogranulomatous osteomyelitis
Actinomyces bovis

Front 54

Common infectious agents causing osteomyelitis

Back 54

Viruses: BVDV, classical swine fever, canine distemper
Bacteria:
cattle: Actinomyces pyogenes, Actinomyces bovis
horses: Rhodococcus equi
Fungi: Aspergillus (dogs)
Protozoa: Leishmania (dogs)