Lecture 29: MSK 2 Flashcards by Emma J

What is fluorosis? What are the gross lesions and why do they develop?

Chronic and severe fluoride toxicity
- mainly cattle (also sheep/horse)

Impairs normal bone metabolism in developing teeth - no impact on mature teeth
- ameloblacsts and odontoblasts are sensitive to excess fluoride

causes
- odontodystrophy (thin/no enamal and dentine) = increased wear to the teeth
- osteofluorosis = periosteal hyperostosis
- lameness = digital/claw fractures

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You suspect fluorosis in a mature cow. Dou you also expect associated digital fractures?

exposure in older animals causes bone pathology only

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What is a primary lesion of lead toxicity and why does it occur?

lead lines
- growth retardation lattice/growth arrest line
- metaphyseal sclerosis

toxic impairment of osteoclasts
- impair remodelling of trabecullae

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What is the impact of vitA toxicity on bone? What is a common signalment?

cats being fed high liver diet

causes physeal damage and osteoporosis

can result in exostosis (nodules) from chronic exposure
= deforming cervical spondylosis in cats over 2yo

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Describe the primary mechanism for vitamin D toxicity in SA and LA respectively

rodenticide

calcinogenic plants

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What is the most important gross lesion of vitD toxicity? How does that differ from the other lesions that can form?

mainly metastatic mineralization in soft tissue after an acute exposure

after chronic exposure skeletal lesions form
- early it is high osteoclast activity (reduce primary spongiosa)
- later increased osteoblast activity (deposition of abnormal matrix)

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What is verratum californicum

a plant

steroidal alkaloid

affecting grazing animals
- sheep at 14d gestation = fetus with cyclopia

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Define osteitis

inflam of bane

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Define osteomyelitis

inflam of bone and the medulla

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Define periosteitis

inflam of periosteum

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What are 3 main routes of entry to the bone

direct - wound or fracture

direct extension from adjacent tissue
- periodontitis
- otitis media

hematogenous - most important

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Where does hematogeous spread bone inflammation localize and why?

in the metaphysis

because…
- capillary/hairpin loops
- fenetrated endothelium
- slow blood flow

predispose to infection

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In what animals is hematogenous infection most common?

young (especially farm animals)

because the physis has no blood supply
- if there is no blood supply then there is no immune protection

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What are 2 common sequelae of bone inflammation and why?

necrosis leading to sequestrun and involucrum

exudate and edema lead to ischemia = infarct

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What causes bacterial osteomyelitis and what is the main consequence

anything that can get into the blood

causing bone necrosis

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What is the causative agent of lumpy jaw? What is the gross lesions and what type of injury does it cause?

Actinomyces bovis

causes honeycomb appearance on cut surface due to bone resorption and necrosis

causing pyogranulomatous osteomyelitis

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How is fungal osteomyelitis spread? What general category of fungi causes fungal osteomyelitis?

hematogenous

dimorphic

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What are the clinical consequences of fungal osteomyelitis?

causing pyogranulomatous - granulomatous inflammation leading to sequestrun and involucrum

bone lysis

periosteal reaction

pathological fractures

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What gross lesion is viral osteomyelitis associated with? What are some examples of causative agents?

growth retardation lattices due to viral destruction of osteoclasts

BVBV (cow)/CSF(pig)/border dz (sheep)/distemper(dog)

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What is metaphyseal osteopathy?

It is an idiopathic and self limiting condition

affects distal radius and ulna (long bones)

suppurative and fibrous osteomyelitis

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What is the common signalment for an animal with metaphyseal osteomyelitis? What is a good diagnostic tool?

young large breed dogs

radiographs - shaw a ‘double physis’

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What is the common signalment for an animal with panosteitis? What are the clinical and radiographic signs?

young large breed dogs (GSD)

causes shifting lameness without inflammation

radiographs:
- expanding foci of fibrovascular tissue
- woven bone
- maturation and resorption
- periosteal reaction

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What is legge-calve perthes disease? What animals does it affect? What is the main clinical consequence?

avascular femoral head necrosis due to a delay or occlusion in vascular development

young small breed dogs

cause collapse of necrotic bone and stretching or rupture of the capital ligaments

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Define hyperostosis

excessive bone formation

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List 3 types of hyperostotic disease

craniomandibular osteopathy hypertrophic osteopathy osteochondroma

What is craniomandibular osteopathy? What animals does it affect?

It is the hyperostosis of the skull bones (mandible/occipital/temporal) westies 4-7mo aka lion jaw

What is hypertrophic osteopathy? How do you treat it?

increased bone production on the periosteum associated with space occupying lung masses (chronic inflammation or neoplasia) can resolve if the space occupying thorax mass is removed

What is an osteochrondroma? What animals does it affect?

It is a benign and incidental exostosis (nodule of periosteal bone) development - grows from the physis and is capped by cartilage - it will stop growing when the skeleton matures young and growing dogs and horses

What is the classification of primary bone neoplasias

mesenchymal (sarcomas if malignant)

How does the prognosis of primary bone neoplasms differ between species

cow/horse = mainly benign dog = mainly malignant cat = 50/50

What are the most prominent characteristics of an osteoma? What species is commonly affected?

horses cranio-facial bone slow growing and benign non painful

What are 2 other differential diagnoses you should think of then considering osteoma

ossifying fibroma fibrous dysplasia

What are most prominent characteristics of an osteosarcoma? What animals are commonly affected?

most common primary bone tumor in dogs and cats affect mainly appendicular skeleton (away from elbow and toward the knee) do not cross joint spaces make osteoid metastasize early to lungs

How are primary bone tumors classified?

peripheral - periosteum - periosteal: from cambrium layer of periosteum - parosteal: from fibrous layer of periosteum central - endosteum

What is the most common type of osteosarcoma? What are the features of this neoplasia?

central it is very progressive metastasized early to the lungs doesn't cross joint spaces Malignant osteoblasts make osteoid creates a starburst pattern on radiograph

Compare chondroma and chondrosarcoma

chondroma - rare (dog and sheep mainly) - flat bones - benign chondrosarcoma - cat/dog/sheep - central or peripheral - malignant

Compare chondrosarcoma and osteosarcoma

chondrosarcoma - can cross joint spaces - make chondroid matrix (looks like hyaline cartilage) osteosarcoma - can't cross joint spaces - make osteoid

What are the typical gross bone lesions associated with lymphoma?

mottles and infarcted yellow bone

List 4 other primary bone tumors

- multilobar - fibrosarcoma - liposarcoma - plasma cell myeloma

What are the common features of a secondary bone neoplasia? Give an example

spread via hematogenous or direct extension carcinoma lung-digit syndrome (feline pulmonary adenocarcinoma)

A cat presents to you with masses on its digits. What is a primary diagnosis? What would be a useful diagnostic?

feline pulmonary adenocarcinoma leading to lung-digit syndrome thoracic radiographs

Differentiate congenital and genetic diseases

congenital: it was present at birth - may or may not be genetic genetic: hereditary

What is congenital hyperostosis? What animal does it affect mainly? What causes it?

It is the thickening (due to periosteal reaction on diaphysis) of front limbs newborn pigs unknown cause (maybe abnormal positioning in utero)

List 4 genetic bone diseases

chondrodysplasia osteopetrosis osteogenesis imperfecta spina bifida

What is chondrodysplasia? What is the main consequence?

generalized cartilage defects preferentially affecting the appendicular skeleton (bones made by endochondral ossification) disproportionate dwarfism

List 5 clinical manifestations of chondrodysplasia

texel chondrydysplasia - sheep spider lamb syndrome - suffolk and Hampshire sheep snorter dwarfism - brachycephalic herford and angus cows lethal bulldog - calves (aborted) breed standards: corgi/daschund/scottish fold

What is osteopetrosis? What animals does it affect?

cattle and horses increased bone density in the metaphysis and diaphysis due to defective osteoclasts - no resorption = accumulation of primary spongiosa a normal physis is maintained

What are the sequelae of osteopetrosis?

pathologic fractures aplastic anemia thrombocytopenia

What is osteogenesis imperfecta? What are the gross lesions?

type 1 collagen defect - rare cause fragile/thin/brittle bone blue areas on the sclera and fragile/pink teeth

Compare brachygnathia inferior and superior

inferior: abnormally small mandible superior: abnormally small maxilla

Define amelia

no limbs

Define hemimelia

no distal limbs

Define phocomelia

no proximal limbs

Define polymelia

extra limbs

Define micromelia

too short limbs

Define syndactyly

fusion of digits

Define polydactyly

extra digits

Define lordosis

ventral deviation of the spine

Define kyphosis

dorsal deviation of the spine

Define scoliosis

lateral deviation of the spine

Define kyphoscoliosis

dorso-lateral deviation of the spine

What is spina bifida

Absence of the dorsal spinal vertebrae - exposed spinal cord

Lecture 29: MSK 2 Flashcards

(63 cards)