Musculoskeletal 4, 5 and Practical Flashcards

Question

Where are synovial sarcomas most commonly found (species, breed, location) How do they grossly appear? What are the three types? How do they appear histologically?

Answer 1

Large breed dogs, most commonly middle-aged, are usually found near a weight baring joint- stifle, elbow, shoulder, tarsus Indistinct borders and may infiltrate along fascial planes- may be cystic Synovioblastic- epithelial Fiboblastic Biphasic Cells are polygonal to spindleoid, oval, prominent nuceli. May be clefts or cavities containing proteinaceous to mucoid material and lined by a poorly defined layer or malignant cells

Answer 2

Flat coat, golden and lab retrievers Gross- rapidly growing, locally aggressive, often in close proximity to a joint- originates from dendritic cells in the synovial membrane. Soft-tissue swellings close to major joints, nodular to diffuse synovial thickening with grey-pink tissue Hist- synovium and capsule infiltrated by malignant histiocytes which have large abundant eosinophilic cytoplasm, anisokaryosis with large irregular nucleoli, frequency mitotic figures and multinucleate cells Pathology- locally aggressive and frequently metastasise

Answer 3

Endomysium- outer most Periphysium- middle the diddle Epimysium- inner most

Answer 4

* Excitation-contraction coupling- leads to calcium release from SR * Causes actin to bind to myosin * ATP causes the release of actin to myosin- process restarts Type 1- slow twitch, oxidative, fatigue resistant Type IIA/B- fast-twitch, glycolytic, rapidly fatigue

Answer 5

Segmental necrosis- regeneration * Damage occurs- if only affecting muscle cells and not basal lamina * Macrophages enter and remove necrotic debris * Satellite cells enter and differentiate into myotube- elongate * They proliferate and replace and restore muscle fibre * Basal lamina keeps myotube in the correct structure If basal lamina is damaged- the structure of satellite cell cannot be maintained leading to more fibrosis and even adipose tissue or mineralisation

Answer 6

Lack of use, cachexia, aging, endocrine disorders, denervation Pathology- lack of proper nervous/endocrine stimulation of myofiber, reduced nourishment Histology- reduction in the size of the myofibrils, chronically- substitution by fibrous tissue or fat Associated conditions- Cachexia- serous atrophy of fat Endocrine- skin conditions

Answer 7

A congenital disorder that causes defects in the myostatin gene and causes a gross increase in muscle size Affects- Belgian blues and sheep Gross- increased muscle size- thighs, rumps, loin and shoulder Histology- increased number/size of normal fibres within affected muscle Was supposed to be better for consumption but it ain't tasty

Answer 8

Pig Fail to sustain quadrupedal position- splay leg attitude Histology- reduced myofibre diameter with decreased myofibrils within muscle fibres and increased cytoplasmic glycogen

Answer 9

Dogs and cats- inherited X linked Pathology- defects in the gene coding for dystrophin- a sarcolemmal associated protein Gross- Dog- muscular atrophy, pale white streak in muscles Cat- muscular hypertrophy, particularly over the neck and shoulder, oesophagus and diaphragm Histology- Dogs- large dark fibres, necrotic fibres, regenerated fibres and mineralisation Cat- marked variation in fibre size with numerous hypertrophied fibres often with internalised nuclei polyphasic necrosis with mineralisation and minimal endomysial fibrosis

Answer 10

Genetic- pigs Path- mutation in ryanodine receptor- dysregulation of excitation-contraction coupling. Characteristed by unregulated release of calcium from SR, leads to excessive myofiber contraction and causes a severe increase in body temp Gross- animals have pale, soft, wet and exudative muscles and develop rapid rigor mortis Histology- oedema and there may be multifocal monophasic injury with hypercontraction

Answer 11

Acquired- circulating autoantibodies against skeletal muscle acetylcholine receptors which leads to a severe decrease in the number of functional receptors Congenital- born with defective NMJs- larger surface area and reduced acetylcholine receptor density Ac- thymoma, episodic collapse

Answer 12

Selenium and vitamin E deficiency- calves, lambs, swine and foals Path- lack of antioxidant activity causes membrane damage and rhabdomyolysis Grossly- lesions are bilaterally symmetrical, there are multifocal white streaks parallel to the fibre direction with mineralisation of cardiac and skeletal muscle Histology- multifocal and polyphasic degeneration of the contractile components of muscle cell Ac- adipose tissue necrosis- yellow fat disease in horses

Answer 13

Exertional myopathy- equine exertional rhabdomyolysis, Monday morning disease Path- aerobic production of ATP is not sufficient- production of ATP by anaerobic glycolysis, lactic acid as catabolite- toxic- membrane damage- rhabdomyolysis- myoglobin in blood- myoglobinuria Gross- occurs mainly in the gluteal, femoral and lumbar muscles Histology- selective necrosis of type II fibres with hyper-contraction Ac- haemoglobulinuria

Answer 14

Streptococcus zooepidemicus- horses Arcanopbacterium pyogenes- cattle, sheep Corynebacterium pseudotuberculosis- horses, sheep, goats Pasturella multocida- cats Traumatic or bacteriaemia Gross- suppurative lesions, abscesses

Answer 15

Wooden tongue is chronic pyogranulomatous fibrosing nodular myositis due to agent actinobacillus ligneresii in cattle Gross- fibrosing, granulomatous Histologically- central focus of radiating clubs of amorphous, eosinophilic material associated with bacteria and neutrophils Botryomycosis

Answer 16

Clostridium speticum- ruminants, horses, swine Path- bacteria penetrate muscle through a slim wound then produce toxins and cause tissue damage Gross- severe oedema, gas bubbles, cellulitis that dissects the muscle fibres Histology- muscle fibres are eosinophilic, necrotic, not many neutrophils

Answer 17

Clostridium chauvoei- cattle and sheep Path- activation of latent spores in the muscle that colonised previously, spored are ingested and subsequently, dissemination through blood occurs and colonise the muscle- reactivated by stressors Gross- muscles are dark red, oedematous with a dry centre and porous patter (gas bubbles) Histology- necrosis, gas bubbles Ac- liver and kidney degeneration, pleuritis, myocarditis

Answer 18

Neospora caninum- dog Toxoplasma gondii- dogs/cats Trichinella spiralis- pigs Sarcocystis spp- horses, cattle, sheep, goats, camelids, pigs Cysticercus spp- cattle, sheep, dogs, pigs

Answer 19

Sarcocystis spp- bovine, ovine Gross- well-demarcated, green focal stripes or patches Histology- eosinophilic, myofiber hyper-contraction, necrosis and separation of endomyseal sheaths and perimyseal trabeculae, there may be fibrosis with lymphocytes, plasma cells and histiocytes

Answer 20

Immune mediated myositis Dog Path- autoantibodies against myosin type M2- only present in masseter, temporal and pterygoid Gross- atrophy of mastication muscles Hist- Acute- eosinophilic myositis Chronic- fibrosis, multifocal lymphocytes

Answer 21

Rhabdomyoma or rhabdomyosarcoma Dogs and horses Histo- morphological variants- subdivided into round cell, spindle cell and mixed. Cross striations are indicative of sarcometric differentiation- strap cells and racket cells

Answer 22

Gross- femur, focally extensive mass localised within the distal diaphysis of the femur involving the medullary cavity and expanding caudally to the periosteum through focal discontinuity of the bone cortex. There are black multifocal areas of haemorrhage with central areas of tissue rarefaction (necrosis). The cranial portion of the cortex exhibit mild thickening. MD- Oestosarcoma

Answer 23

Kiddy cortex is affected by a multifocal to coalescing wite to tan firm bulging areas MD- kidney severe, multifocal to coalescing, chronic, intersititial nephritis

Answer 24

Condition- fibrous osteodystrophy Pathogenic link- 1. chronic kidney lesion, damage to glomerular filtration 2. Phosphorous retention- increase in PTH 3. Increase in osteoblasts activity with mineralised bone reabsorption and mesenchymal cells 4. Failure of differentiation into osteoblasts with the production of collagen 5. Lack of collagen reabsorption by osteoclasts

Answer 25

Gross- acetabulum is shallow and the femur head is flattened. In both areas, articular cartilage is lost (bone eburnation). Ligament teres are absent. There is thickening and roughening of the synovia all around with diffuse projections (villous hyperplasia) Condition- Hip Dysplasia Provide the cause- genetic conditions

Answer 26

Gross description- there is a diffuse complex, multilobular, coral-like new bone proliferation extending on the periosteum of all the bones. Condition name- Marie's disease, hypertrophic osteopathy Link Space occupying lesion, changes in haemodynamics of blood to limbs- increase vascularization of periosteum- excessive periosteal new bone formation

Answer 27

GD- approximately 70% of the muscle there are linear, parallel multifocal to coalescing/focally extensive white streaks MD- muscle, diffuse/multifocal to coalescing, acute/subacute, muscle necrosis/myositis

Answer 28

Description- 60% of the left slide is affected by diffuse fragmentation of myofibres with associated infiltrating macrophages and other inflammatory cells (rhabdomyolysis) Cause- Poor nutrition causes vitamin E and selenium deficiency- therefore not having normal anti-oxidant activity causing membrane damage

Musculoskeletal 4, 5 and Practical Flashcards

(55 cards)