Pathology: Skeletal
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Questions and Answers

What does Wolff’s law state regarding bone tissue?

  • Bones are only resorbed and not deposited.
  • Bone strength remains constant regardless of mechanical stress.
  • Bone does not respond to mechanical forces.
  • Bone is deposited where it is required and resorbed where it is not. (correct)

    • Reduced mechanical stress on bones can lead to increased bone strength.

    False

    What is the primary consequence of the presence of a rigid implant after a fracture has healed?

    Bone atrophy and reduced strength.

    The distal radial physis is particularly susceptible to __________ injury.

    <p>traumatic</p> Signup and view all the answers

    Which of the following responses is NOT a basic cellular response of bone tissue?

    <p>Mortality</p> Signup and view all the answers

    Match the following terms with their correct definitions:

    <p>Hypertrophy = Increase in cell size Atrophy = Decrease in cell size Hyperplasia = Increase in the number of cells Necrosis = Cell death due to injury</p> Signup and view all the answers

    Slipped epiphysis is a term used for complete separation through the growth plate.

    <p>True</p> Signup and view all the answers

    What is the prognosis for a complete separation through the growth plate if the epiphyseal vasculature remains intact?

    <p>Very good.</p> Signup and view all the answers

    What occurs when fracture ends are perfectly aligned and rigidly immobilized?

    <p>Callus formation is minimal or non-existent</p> Signup and view all the answers

    Rigid fracture repair promotes contact healing.

    <p>True</p> Signup and view all the answers

    Name the three common causes of impaired fracture repair.

    <p>Infection, instability, inadequate blood supply</p> Signup and view all the answers

    The absence of _____ at the fracture site can lead to impaired healing.

    <p>blood supply</p> Signup and view all the answers

    Match the following terms with their definitions:

    <p>Chondrodysplasia = Disordered skeletal development Syndactyly = Fusion of digits Polydactyly = Presence of supernumerary digits Kyphosis = Abnormal dorsal curvature of the spinal column</p> Signup and view all the answers

    What type of bone repair involves resorption canals being formed by osteoclasts?

    <p>Primary bone repair</p> Signup and view all the answers

    Pseudoarthrosis can develop from excessive movement between bone ends.

    <p>True</p> Signup and view all the answers

    What is the primary goal of the reparative phase in fracture healing?

    <p>Callus formation</p> Signup and view all the answers

    The _____ type of chondrodysplasia in cattle often results in severe skeletal abnormalities.

    <p>bulldog</p> Signup and view all the answers

    What condition is characterized by abnormal curvature of the spinal column ventrally?

    <p>Lordosis</p> Signup and view all the answers

    Chondrodysplasias result in proportionate dwarfism.

    <p>False</p> Signup and view all the answers

    What major factor can interfere with new bone formation during fracture healing?

    <p>Infection</p> Signup and view all the answers

    _____ is a common hereditary chondrodysplasia in sheep.

    <p>Spider Lamb syndrome</p> Signup and view all the answers

    What impact do corticosteroids have on fracture healing?

    <p>They can interfere with bone healing</p> Signup and view all the answers

    Which condition may result from slipped epiphysis of the femoral head?

    <p>Avascular necrosis</p> Signup and view all the answers

    Lead to formation of a bony bridge between the metaphysis and epiphysis can occur if fractures cross the physis with displacement of fragments.

    <p>True</p> Signup and view all the answers

    What type of fracture is characterized by extension along the physis and out through the metaphysis?

    <p>Physeal fracture</p> Signup and view all the answers

    A common cause of limb deformity in dogs is ________ of the distal ulna physis.

    <p>premature closure</p> Signup and view all the answers

    Match the following types of fractures with their characteristics:

    <p>Avascular necrosis = Result from slipped epiphysis Pathological fracture = Occurs due to underlying disease Salter Harris fracture = Characterized by displacement and bony bridge Endochondral ossification = Replacement of cartilage with bone during repair</p> Signup and view all the answers

    What is often the first event in uncomplicated fracture repair?

    <p>Formation of a hematoma</p> Signup and view all the answers

    Crushing injuries predominantly affect the metaphysis.

    <p>False</p> Signup and view all the answers

    Which forces can lead to angular limb deformities?

    <p>Growth plate damage</p> Signup and view all the answers

    In adults, residual changes at the fracture site, such as ______, may persist after healing.

    <p>thickening of the periosteal bone surface</p> Signup and view all the answers

    What happens if the adjacent radius escapes injury after a fracture?

    <p>Disturbance in syncrony</p> Signup and view all the answers

    The size of a fracture callus is inversely related to the movement between fractured bone ends.

    <p>False</p> Signup and view all the answers

    What type of remodeling is more rapid in young animals than in adults?

    <p>Modeling of the callus</p> Signup and view all the answers

    The formation of ______ ultimately replaces the cartilage in the fracture callus during repair.

    <p>woven bone</p> Signup and view all the answers

    Match the following types of deformities with their descriptions:

    <p>Valgus deformity = Lateral deviation of the limb Varus deformity = Medial deviation of the limb Cranial bowing of the radius = Shortened limb due to growth disturbance Angular limb deformity = Result of growth plate damage</p> Signup and view all the answers

    What is a characteristic feature of spider lamb syndrome?

    <p>Angular deformities of the forelimbs</p> Signup and view all the answers

    Manganese deficiency in pregnant cows can lead to skeletal deformities in their calves.

    <p>True</p> Signup and view all the answers

    What type of growth abnormality can severe malnutrition cause in bone growth?

    <p>Narrow growth plates and growth arrest lines</p> Signup and view all the answers

    Copper deficiency is associated with ___________ of collagen molecules which is important for bone strength.

    <p>cross-linkage</p> Signup and view all the answers

    Match the deficiency with its effect on bone health:

    <p>Manganese = Decreased cartilage glycosaminoglycan production Zinc = Possible skeletal defects Copper = Increased bone fragility Vitamin C = Impaired collagen synthesis</p> Signup and view all the answers

    Which of the following is a common facial deformity associated with spider lamb syndrome?

    <p>Roman nose</p> Signup and view all the answers

    Vitamin C deficiency is predominantly observed in species that can synthesize ascorbic acid.

    <p>False</p> Signup and view all the answers

    What is a potential outcome of severe skeletal abnormality due to nutritional deficiency?

    <p>Euthanasia may be the best option.</p> Signup and view all the answers

    Certain __________ agents can mimic genetic diseases in developing animals.

    <p>teratogenic</p> Signup and view all the answers

    Which nutrient deficiency is associated with osteochondrosis in deer?

    <p>Copper</p> Signup and view all the answers

    Skeletal deformities due to zinc deficiency during gestation have been conclusively proven.

    <p>False</p> Signup and view all the answers

    What are growth arrest lines indicative of?

    <p>Recurrent episodes of retarded growth</p> Signup and view all the answers

    Plant toxicities may influence skeletal __________ in young growing animals.

    <p>remodeling</p> Signup and view all the answers

    Match the deficiency with the associated condition:

    <p>Copper = Bone fragility Vitamin C = Scurvy Manganese = Skeletal deformities Zinc = Potential bone defects in calves</p> Signup and view all the answers

    What aspect of spider lamb syndrome typically develops within the first month of life?

    <p>Disproportionately long limbs</p> Signup and view all the answers

    Which of the following skeletal abnormalities are typically associated with consistent presentations due to genetic causes?

    <p>Inherited defects</p> Signup and view all the answers

    Most cases of osteoporosis in animals are primarily caused by hormonal imbalances.

    <p>False</p> Signup and view all the answers

    What type of samples should be collected if a genetic aetiology is suspected in affected animals?

    <p>Whole blood, liver, ear notch, or tail hair samples</p> Signup and view all the answers

    Osteoporosis is characterized by a reduction in the ______ of bone, while the quality remains normal.

    <p>quantity</p> Signup and view all the answers

    Match the following metabolic bone diseases with their characteristics:

    <p>Rickets = Common in young animals and results from vitamin D deficiency Osteomalacia = Softening of bones due to inadequate mineralization Fibrous osteodystrophy = Excessive fibrous tissue in response to bone loss Osteoporosis = Reduction in bone quantity with normal quality</p> Signup and view all the answers

    What is a common outcome of starvation in young growing animals?

    <p>Growth arrest lines</p> Signup and view all the answers

    Calcium deficiency is a common cause of osteoporosis in sheep and cattle.

    <p>False</p> Signup and view all the answers

    What might be the first indication that an animal is suffering from osteoporosis?

    <p>Bone fracture without evidence of excessive trauma</p> Signup and view all the answers

    The occurrence of fractures in farmed livestock may suggest increased bone ______.

    <p>fragility</p> Signup and view all the answers

    Which nutrient deficiency is associated with osteoporosis in various animal species?

    <p>Copper</p> Signup and view all the answers

    Radiographic procedures are highly sensitive for detecting early stages of osteoporosis.

    <p>False</p> Signup and view all the answers

    What specific type of fracture is seen frequently in first calving dairy heifers in New Zealand?

    <p>Spiral fracture down the diaphysis of the humerus</p> Signup and view all the answers

    _______ osteodystrophy is more likely to occur in rapidly growing pigs due to calcium deficiency.

    <p>Fibrous</p> Signup and view all the answers

    Match the following animal conditions to their nutritional causes:

    <p>Osteoporosis = Calcium deficiency Rickets = Vitamin D deficiency Fibrous osteodystrophy = Calcium starvation Osteogenesis imperfecta = Genetic defect affecting collagen</p> Signup and view all the answers

    What nutrient deficiencies are associated with disproportionate dwarfism in farm animals?

    <p>Manganese and Zinc</p> Signup and view all the answers

    Congenital skeletal abnormalities in farm animals are always caused by genetic factors.

    <p>False</p> Signup and view all the answers

    What is one consequence of Cu deficiency in farm animals?

    <p>Osteoporosis</p> Signup and view all the answers

    A high incidence of skeletal disease in newborn animals often suggests a __________ aetiology.

    <p>non-genetic</p> Signup and view all the answers

    Match the nutrient deficiency with its corresponding skeletal issue:

    <p>Manganese = Disproportionate dwarfism Copper = Osteoporosis Vitamin C = Subperiosteal haemorrhage Zinc = Growth arrest lines</p> Signup and view all the answers

    Which situation may lead to a high percentage of skeletal deformities?

    <p>Feeding inappropriate diets during early pregnancy</p> Signup and view all the answers

    Chondrodysplastic dwarfism can be confused with nutritional dwarfism.

    <p>True</p> Signup and view all the answers

    What are the consequences of teratogenic virus infections during pregnancy?

    <p>Outbreaks of congenital abnormalities</p> Signup and view all the answers

    Skeletal resilience should be evaluated for conditions like __________ and osteopetrosis.

    <p>osteogenesis imperfecta</p> Signup and view all the answers

    Which of the following is an example of a skeletal disease with incomplete penetrance?

    <p>Spider lamb syndrome</p> Signup and view all the answers

    Recessively inherited diseases affect 50% of the offspring of two heterozygous parents.

    <p>False</p> Signup and view all the answers

    In which part of the animal should the bone examination focus during post-mortem?

    <p>Rapidly growing physes</p> Signup and view all the answers

    A thorough __________ history is crucial to distinguishing genetic from non-genetic causes of skeletal abnormalities.

    <p>clinical</p> Signup and view all the answers

    What is a common outcome of exposure to teratogenic agents during early pregnancy?

    <p>High variability of lesions among offspring</p> Signup and view all the answers

    Match the following conditions with their characteristics:

    <p>Osteogenesis imperfecta = Bone fragility Chondrodysplasia = Hereditary dwarfism Nutritional dwarfism = Mineral deficiency Teratogenic exposure = Environmentally induced defects</p> Signup and view all the answers

    Which of the following factors is NOT associated with osteoporosis in animals?

    <p>Excessive calcium intake</p> Signup and view all the answers

    Gastrointestinal parasitism is a well-known cause of osteoporosis in animals.

    <p>True</p> Signup and view all the answers

    What role do corticosteroids play in osteoporosis?

    <p>They decrease bone formation and increase bone resorption.</p> Signup and view all the answers

    Rickets occurs in _____ animals, while osteomalacia occurs only in _____ animals.

    <p>young, adult</p> Signup and view all the answers

    Match the disease with its associated deficiency:

    <p>Rickets = Vitamin D deficiency Osteomalacia = Phosphorus deficiency Corticosteroid-induced osteoporosis = Corticosteroid use Disuse osteoporosis = Muscular inactivity</p> Signup and view all the answers

    What is a classic feature of rickets?

    <p>Enlargement of costochondral junctions</p> Signup and view all the answers

    Disuse osteoporosis is caused by increased weight-bearing activity.

    <p>False</p> Signup and view all the answers

    Which animals are particularly susceptible to vitamin D deficiency?

    <p>Sheep, alpacas, and llamas.</p> Signup and view all the answers

    Pathological fractures are commonly found in the _____ in human patients with osteoporosis.

    <p>vertebral bodies</p> Signup and view all the answers

    Match the type of osteoporosis with its primary cause:

    <p>Corticosteroid-induced osteoporosis = Corticosteroids Disuse osteoporosis = Muscular inactivity Osteoporosis from gastrointestinal parasitism = Malabsorption Osteoporosis from inflammatory bowel disease = Corticosteroid therapy</p> Signup and view all the answers

    What is the main reason for the occurrence of osteomalacia in adults?

    <p>Defective mineralization</p> Signup and view all the answers

    Phosphorus deficiency is a common cause of rickets in animals grazing pastures low in phosphorus.

    <p>True</p> Signup and view all the answers

    What characterizes the gross lesions of osteoporosis?

    <p>Markedness in areas composed predominantly of cancellous bone.</p> Signup and view all the answers

    Cancellous bone in the metaphyses and _____ of long bones may be reduced and more porous than normal.

    <p>epiphyses</p> Signup and view all the answers

    What is the hallmark sign of rickets in long bones?

    <p>Irregular thickening of physes</p> Signup and view all the answers

    Pathological fractures due to osteomalacia are limited to the limbs only.

    <p>False</p> Signup and view all the answers

    What is a common cause of fibrous osteodystrophy in animals?

    <p>Chronic renal disease or dietary imbalance of calcium and phosphorus</p> Signup and view all the answers

    Secondary hyperparathyroidism is commonly caused by chronic __________ disease or deficiencies in mineral intake.

    <p>renal</p> Signup and view all the answers

    Which animal is NOT commonly affected by fibrous osteodystrophy?

    <p>Sheep</p> Signup and view all the answers

    Nutritional secondary hyperparathyroidism can occur from excessive phosphorus intake, even with normal calcium levels.

    <p>True</p> Signup and view all the answers

    What is the ideal calcium to phosphorus ratio for preventing skeletal abnormalities?

    <p>1:1</p> Signup and view all the answers

    The irregular thickening of the articular cartilage is seen in severe cases of __________.

    <p>rickets</p> Signup and view all the answers

    Which skeletal manifestation is primarily associated with primary hyperparathyroidism?

    <p>Widespread mineralization of soft tissues</p> Signup and view all the answers

    Match the following conditions with their associated characteristics:

    <p>Rickets = Irregular thickening of physes Fibrous Osteodystrophy = Bone resorption and fibrous tissue proliferation Osteomalacia = Pathological fractures in adults Secondary hyperparathyroidism = Chronic renal disease or dietary imbalance</p> Signup and view all the answers

    Pathological changes in fibrous osteodystrophy are most pronounced in adult animals.

    <p>False</p> Signup and view all the answers

    What condition can result in the collapse of articular surfaces in severe cases?

    <p>Osteomalacia or fibrous osteodystrophy</p> Signup and view all the answers

    The condition caused by prolonged feeding of diets high in grain is commonly referred to as __________ disease.

    <p>bran</p> Signup and view all the answers

    What condition is most commonly associated with osteopenia in affected animals?

    <p>Renal secondary hyperparathyroidism</p> Signup and view all the answers

    Which of the following animal species is particularly sensitive to high phosphorus diets?

    <p>Horses</p> Signup and view all the answers

    What is a common symptom of nutritional secondary hyperparathyroidism in dogs and cats?

    <p>Skeletal abnormalities</p> Signup and view all the answers

    Nutritional secondary hyperparathyroidism occurs in reptiles due to diets high in calcium.

    <p>False</p> Signup and view all the answers

    What is the primary cause of fibrous osteodystrophy in animals?

    <p>Low plasma calcium concentration</p> Signup and view all the answers

    The characteristic lesion of rickets is segmental thickening of the _____

    <p>physis</p> Signup and view all the answers

    Which breed of dog is particularly susceptible to Legg-Calvé-Perthes disease?

    <p>Miniature Poodle</p> Signup and view all the answers

    The osteonecrosis in Legg-Calvé-Perthes disease is usually unilateral.

    <p>False</p> Signup and view all the answers

    What is often the critical bone to examine when investigating fracture outbreaks?

    <p>Rib with costochondral junction</p> Signup and view all the answers

    Accelerated resorption of cancellous bones in the maxilla and mandibles can result in a condition known as _____ jaw.

    <p>rubber</p> Signup and view all the answers

    Match the following bone diseases with their primary causes:

    <p>Osteoporosis = Starvation or Cu deficiency Rickets = Vitamin D or phosphorus deficiency Fibrous osteodystrophy = Low plasma calcium concentration Legg-Calvé-Perthes Disease = Avascular necrosis of the femoral head</p> Signup and view all the answers

    What is commonly the first evident sign of renal secondary hyperparathyroidism in adult dogs?

    <p>Resorption of alveolar socket bone</p> Signup and view all the answers

    Fracture outbreaks in livestock are often caused by metabolic bone disease such as osteoporosis.

    <p>True</p> Signup and view all the answers

    What role does increased intracapsular pressure play in Legg-Calvé-Perthes disease?

    <p>It may occlude veins draining the femoral head.</p> Signup and view all the answers

    Excessive movement between bone ends can lead to the development of _____ arthrosis.

    <p>pseudo</p> Signup and view all the answers

    What type of bone changes are indicative of fibrous osteodystrophy?

    <p>Replacement by fibrous connective tissue</p> Signup and view all the answers

    What is a significant consequence of Legg-Calve-Perthes (LCP) disease?

    <p>Necrosis and collapse of the femoral head</p> Signup and view all the answers

    Bacterial osteomyelitis in dogs is more commonly a result of fractures than in other animals.

    <p>True</p> Signup and view all the answers

    What is a common cause of osteomyelitis in horses less than 4 months old?

    <p>Escherichia coli</p> Signup and view all the answers

    The condition known as __________ occurs in ruminants and is primarily caused by Actinomyces bovis.

    <p>mandibular osteomyelitis</p> Signup and view all the answers

    Match the bacteria to their respective host species:

    <p>Escherichia coli = Horses (foals) Streptococcus spp = Dogs and Cats Salmonella spp = Ruminants Trueperella pyogenes = Vertebral osteomyelitis</p> Signup and view all the answers

    Which of the following is NOT typically associated with the transmission of infection from metaphysis to epiphysis?

    <p>Mature skeleton morphology</p> Signup and view all the answers

    The capillaries in cartilage canals are fenestrated, allowing bacteria to escape into the bone marrow.

    <p>True</p> Signup and view all the answers

    What anatomical feature restricts the spread of infection from the metaphysis to the epiphysis?

    <p>Physis</p> Signup and view all the answers

    Bacterial infections of bones are most often centred on the __________ cavity.

    <p>medullary</p> Signup and view all the answers

    Match the following conditions with their description:

    <p>Osteomyelitis = Infection of bone often due to bacteria LCP = Necrosis of femoral head in miniature breeds Diskospondylitis = Infection of intervertebral disks Mandibular osteomyelitis = Lumpy jaw in cattle</p> Signup and view all the answers

    Which of the following conditions is characterized by pathological fractures due to vertebral osteomyelitis?

    <p>Diskospondylitis</p> Signup and view all the answers

    Infection localized in young skeletal systems can lead to significant clinical manifestations immediately.

    <p>False</p> Signup and view all the answers

    What is the primary cause of osteomyelitis in the long bones of young dogs?

    <p>Compound fractures</p> Signup and view all the answers

    ____________ are often the first event in the process of bacterial infections of bone.

    <p>Oedema and acute purulent inflammation</p> Signup and view all the answers

    What is the classic lesion associated with actinomycosis in cattle?

    <p>Mandible involvement</p> Signup and view all the answers

    Actinomyces bovis is highly virulent and can invade bone without the need for prior tissue injury.

    <p>False</p> Signup and view all the answers

    What appearance does the affected mandible have in cases of A. bovis infection?

    <p>Honeycomb</p> Signup and view all the answers

    Lumpy jaw is specifically known as __________.

    <p>actinomycosis</p> Signup and view all the answers

    Which animal is most commonly affected by osteosarcoma?

    <p>Dogs</p> Signup and view all the answers

    Osteosarcoma occurs with equal frequency in male and female dogs.

    <p>False</p> Signup and view all the answers

    What is the mean age of occurrence for osteosarcoma in dogs?

    <p>7-8 years</p> Signup and view all the answers

    Osteosarcoma occurs predominantly in the __________ skeleton.

    <p>appendicular</p> Signup and view all the answers

    Match the following tumours with their characteristics:

    <p>Osteosarcoma = Most common primary bone neoplasm in dogs Benign tumours = More common in horses and cattle than malignant Malignant tumours = Usually more common in dogs than in cats Tumour-like lesions = Variety found in veterinary medicine</p> Signup and view all the answers

    What is often found in the pus of affected tissue in actinomycosis?

    <p>Sulphur granules</p> Signup and view all the answers

    In cattle, the maxilla is most commonly involved in actinomycosis.

    <p>False</p> Signup and view all the answers

    What is the most effective biopsy technique for bone lesions?

    <p>Excised lesion</p> Signup and view all the answers

    Chronic irritation and repair can lead to osteosarcoma occurring at sites of __________ injury.

    <p>chronic</p> Signup and view all the answers

    What is the primary cause of bacterial osteomyelitis in farm animals?

    <p>Bacteraemia</p> Signup and view all the answers

    What is the primary consequence of Type III herniations of intervertebral disks in the spinal canal?

    <p>Contusive injury to the spinal cord</p> Signup and view all the answers

    Ischaemic myelopathy is usually associated with Type I herniations of intervertebral disks.

    <p>False</p> Signup and view all the answers

    What condition can lead to ischaemic myelopathy caused by fibrocartilaginous embolism?

    <p>Degenerative disk disease</p> Signup and view all the answers

    Cervical disk protrusions usually result in ______ neurological signs than thoracolumbar region protrusions.

    <p>less severe</p> Signup and view all the answers

    Match the following conditions with their associated characteristics:

    <p>Type I herniation = Associated with severe clinical signs Type II herniation = Most common in non-chondrodystrophic dogs Ischaemic myelopathy = Caused by fibrocartilaginous embolism Type III herniation = Results from trauma leading to spinal cord injury</p> Signup and view all the answers

    What is a common cause of a non-diagnostic bone biopsy sample?

    <p>Failure of the biopsy needle to penetrate the cortex</p> Signup and view all the answers

    Using a Jamshidi biopsy needle carries no risk of pathologic fracture.

    <p>False</p> Signup and view all the answers

    What is the main purpose of performing a wedge biopsy?

    <p>To collect larger samples from lesions or areas where the cortex is missing.</p> Signup and view all the answers

    Cytological specimens may be obtained using a ____________ needle or catheter stylet for the diagnosis of primary bone tumors.

    <p>fine</p> Signup and view all the answers

    Match the sampling technique with its characteristic:

    <p>Trephine biopsy = Allows for larger sample collection Fine needle aspiration = Least invasive method Open biopsy = Higher risk of post-surgical complications Wedge biopsy = Used for large lesions</p> Signup and view all the answers

    What is a characteristic feature of osteosarcoma as seen on radiographs?

    <p>Ill-defined zone of transition between normal and affected bone</p> Signup and view all the answers

    Reactive bone is more commonly found at the center of neoplastic bone lesions.

    <p>False</p> Signup and view all the answers

    Which sampling technique showed increased diagnostic accuracy when both central and edge samples were taken?

    <p>Trephine biopsy</p> Signup and view all the answers

    If the cortex is weakened, a ___________ may be sufficient for diagnosing a primary bone tumor.

    <p>fine needle aspiration</p> Signup and view all the answers

    Match the characteristics of bone lesions with the corresponding factors:

    <p>Malignant neoplasia = Rapid rate of osseous change Fungal osteomyelitis = Uncommon in NZ Benign lesions = Gradual changes over time Lytic lesions = Destroy underlying bone</p> Signup and view all the answers

    What is the primary characteristic of telangiectatic osteosarcomas?

    <p>Soft and dark red appearance</p> Signup and view all the answers

    Osteosarcomas predominantly erode cortical bone but rarely invade the adjacent soft tissues.

    <p>False</p> Signup and view all the answers

    What is the likely effect of trauma or biomechanical factors on cartilage?

    <p>Creating ischaemic damage</p> Signup and view all the answers

    The aetiology and pathogenesis of osteochondrosis are well-understood.

    <p>False</p> Signup and view all the answers

    What increases the risk of misdiagnosis when a core biopsy is not performed?

    <p>Limb-sparing surgery can be performed when it is not appropriate.</p> Signup and view all the answers

    What structural change occurs in cartilage canals during bone development?

    <p>They become filled with hyaline cartilage.</p> Signup and view all the answers

    The technique of ultrasound can be useful in guiding sampling during cases of marked ____________.

    <p>cortical lysis</p> Signup and view all the answers

    The epiphyseal cartilage of the articular-epiphyseal cartilage complex is dependent on the blood supply delivered by __________.

    <p>cartilage canal vessels</p> Signup and view all the answers

    Match the following lesions with their associated species:

    <p>Pigs = Joint surfaces of the medial humeral and femoral condyles Dogs = Caudal aspect of the humeral head Horses = Developmental orthopaedic disease Cattle = Occasional reports of osteochondrosis</p> Signup and view all the answers

    Which of the following factors has been suggested to play a role in osteochondrosis?

    <p>Nutritional imbalance</p> Signup and view all the answers

    Osteochondrosis commonly affects females more than males in certain species.

    <p>False</p> Signup and view all the answers

    What is a significant consequence of local ischaemia in developing cartilage?

    <p>Necrosis and delayed endochondral ossification.</p> Signup and view all the answers

    Copper deficiency is linked to a potential weakening of __________ molecules in articular cartilage.

    <p>collagen</p> Signup and view all the answers

    What can lead to the formation of loose bodies or 'joint mice' in joints?

    <p>Trauma to articular cartilage</p> Signup and view all the answers

    All species show a similar prevalence of osteochondrosis.

    <p>False</p> Signup and view all the answers

    Which enzyme is copper a component of, that helps strengthen collagen?

    <p>Lysyl oxidase</p> Signup and view all the answers

    Match the types of cartilage lesions with their characteristics:

    <p>Osteochondritis dissecans = Inflammation in the synovium with necrotic cartilage present Subchondral cystic lesions = Initially degenerate or necrotic cartilage replaced with fibrous tissue Physeal lesions = Cone-shaped foci of retained cartilage extending into the metaphysis Articular lesions = Lesions at sites of greatest weight-bearing force</p> Signup and view all the answers

    What nutritional factor is linked to osteochondrosis in very young deer?

    <p>Copper deficiency</p> Signup and view all the answers

    Small defects in cartilage lesions are likely to cause significant problems.

    <p>False</p> Signup and view all the answers

    Which of the following is a common symptom of cervical vertebral malformation-malarticulation in horses?

    <p>Ataxia of the hind limbs</p> Signup and view all the answers

    Hip dysplasia affects only large and giant dog breeds.

    <p>False</p> Signup and view all the answers

    What is the primary lesion thought to be associated with osteochondrosis?

    <p>Ischaemic necrosis of articular chondrocytes</p> Signup and view all the answers

    Cervical stenotic myelopathy is commonly referred to as __________ syndrome.

    <p>wobbler</p> Signup and view all the answers

    Match the following developmental orthopaedic diseases with their corresponding descriptions:

    <p>Osteochondrosis = A condition involving abnormal growth of cartilage Physitis = Inflammation of growth plates Flexural limb deformities = Conditions related to joint laxity or contracture Subchondral cystic lesions = Cysts formed underneath joint cartilage</p> Signup and view all the answers

    Which of the following breeds is most commonly affected by static cervical canal stenosis?

    <p>Great Dane</p> Signup and view all the answers

    All skeletal diseases in horses are classified under developmental orthopaedic disease.

    <p>False</p> Signup and view all the answers

    What nutritional deficiency has been linked to osteochondrosis in deer?

    <p>Copper deficiency</p> Signup and view all the answers

    Rapid growth is a risk factor for __________ lesions in dogs.

    <p>hip dysplastic</p> Signup and view all the answers

    Match the following terms with their definitions:

    <p>Osteophytes = Bony projections that develop along joint margins Subluxation = Partial dislocation of a joint Articular process = Bone structures forming the joints Avulsion fracture = Fragment of bone that has been pulled away by a tendon or ligament</p> Signup and view all the answers

    Which developmental disease includes conditions such as contractures and laxity in limbs?

    <p>Flexural limb deformities</p> Signup and view all the answers

    Degenerative joint disease implies an inflammatory origin.

    <p>False</p> Signup and view all the answers

    In horses, which age range is most commonly affected by dynamic cervical compression?

    <p>8 to 18 months</p> Signup and view all the answers

    Developmental orthopaedic diseases may not be consistent over time due to their __________ nature.

    <p>fluid</p> Signup and view all the answers

    Which type of degenerative joint disease is associated with an underlying abnormality in the joint?

    <p>Secondary degenerative joint disease</p> Signup and view all the answers

    Fibrillation occurs as the first gross lesion in degenerative joint disease.

    <p>True</p> Signup and view all the answers

    What is the term used when articular cartilage becomes completely ulcerated and exposed bone is smooth?

    <p>Eburnation</p> Signup and view all the answers

    The nucleus pulposus in chondrodystrophic breeds starts to degenerate early in life, typically by _____ years of age.

    <p>one</p> Signup and view all the answers

    Match the type of intervertebral disk herniation with its characteristics:

    <p>Type I = Massive extrusion of degenerate nuclear material Type II = Partial herniation with bulging of outer lamellae Type III = A gradual degeneration of disks without herniation Type IV = Immediate and catastrophic herniation affecting the spinal cord</p> Signup and view all the answers

    What is a consistent gross feature of degenerative joint disease?

    <p>Formation of osteophytes</p> Signup and view all the answers

    Most disk herniations occur in non-chondrodystrophic dog breeds.

    <p>False</p> Signup and view all the answers

    What major difference exists between intervertebral disk degeneration in chondrodystrophic and non-chondrodystrophic dog breeds?

    <p>Chondrodystrophic breeds degenerate early and mineralize, while non-chondrodystrophic breeds maintain their normal nucleus pulposus longer.</p> Signup and view all the answers

    Degeneration of the annulus fibrosus in both chondrodystrophic and non-chondrodystrophic dogs begins at _____ of age.

    <p>one year</p> Signup and view all the answers

    Match the breeds to their susceptibility to intervertebral disk disease:

    <p>Dachshund = Chondrodystrophic Beagle = Chondrodystrophic Labrador Retriever = Non-chondrodystrophic Golden Retriever = Non-chondrodystrophic</p> Signup and view all the answers

    What is indicated by the activity of cytokines and collagenases in the context of degenerative joint disease?

    <p>Destroys articular cartilage</p> Signup and view all the answers

    Type II herniations are more severe than Type I herniations.

    <p>False</p> Signup and view all the answers

    What can result from chronic instability in a joint?

    <p>Degenerative joint disease</p> Signup and view all the answers

    Formation of a thickened joint capsule occurs in animals with _____ joint disease.

    <p>degenerative</p> Signup and view all the answers

    Which species is most commonly affected by plasma cell myeloma?

    <p>Dogs</p> Signup and view all the answers

    Plasma cell myeloma is more frequently found in female dogs than in males.

    <p>False</p> Signup and view all the answers

    Name a common location for osteolytic lesions in dogs with plasma cell myeloma.

    <p>Vertebrae</p> Signup and view all the answers

    Osteochondrosis primarily affects _____, horses, and large breeds of dog.

    <p>pigs</p> Signup and view all the answers

    Match the following types of tumors with their characteristics:

    <p>Osteosarcoma = Highly malignant bone tumor Plasma cell myeloma = Causes multifocal lytic lesions and hyperglobulinaemia Histiocytic sarcoma = Locally aggressive and often metastasizes Synovial myxoma = Benign but locally invasive tumor of joints</p> Signup and view all the answers

    What is a common clinical feature of multiple plasma cell tumors?

    <p>Hypercalcaemia</p> Signup and view all the answers

    Malignant neoplasms originating in soft tissues rarely involve bone secondarily.

    <p>False</p> Signup and view all the answers

    What type of bone tumor is characterized by lesions occurring away from the elbow and towards the knee?

    <p>Osteosarcoma</p> Signup and view all the answers

    ___ is a key feature of synovial myxoma.

    <p>Local invasiveness</p> Signup and view all the answers

    Which of the following conditions is often associated with hyperviscosity syndrome?

    <p>Plasma cell myeloma</p> Signup and view all the answers

    Pathological fractures can result from lytic bone lesions caused by plasma cell myeloma.

    <p>True</p> Signup and view all the answers

    What is the prognosis for histiocytic sarcoma in dogs?

    <p>Poor</p> Signup and view all the answers

    What is a key distinction in the occurrence of bone tumors in cats compared to dogs?

    <p>Cats have limited data on skeletal metastases.</p> Signup and view all the answers

    Synovial myxoma may be misdiagnosed as a malignant tumor due to its ability to invade _____.

    <p>bone</p> Signup and view all the answers

    What is the common prognosis for dogs diagnosed with appendicular osteosarcomas?

    <p>3-4 months</p> Signup and view all the answers

    Cytology is always reliable for diagnosing osteosarcoma.

    <p>False</p> Signup and view all the answers

    What special stain can assist in distinguishing osteoblasts from other mesenchymal cells?

    <p>ALP (bone alkaline phosphatase)</p> Signup and view all the answers

    The most common site of metastasis for osteosarcoma is the __________.

    <p>lungs</p> Signup and view all the answers

    Match the following tumours with their characteristics:

    <p>Osteosarcoma = Most malignant group of tumours in dogs Chondrosarcoma = Second in incidence to osteosarcoma in dogs Fibrosarcoma = High invasive potential with local recurrence Haemangiosarcoma = Malignant tumour of blood vessels</p> Signup and view all the answers

    Which breed is NOT mentioned as commonly affected by chondrosarcoma?

    <p>Beagle</p> Signup and view all the answers

    Chondrosarcomas typically metastasize earlier than osteosarcomas.

    <p>False</p> Signup and view all the answers

    What is the median survival time for cats with appendicular osteosarcoma following treatment by amputation?

    <p>49.2 months</p> Signup and view all the answers

    Increased ALP levels before surgery in dogs with appendicular osteosarcomas have been associated with __________ survival time post-surgery.

    <p>shorter</p> Signup and view all the answers

    Match the following types of bone tumours with their descriptions:

    <p>Multilobular tumour = Slow-growing tumour of the skull Fibrosarcoma = High local invasive potential Osteosarcoma = Most common primary bone tumour in dogs Haemangiosarcoma = Malignant, often leading to multiple lytic lesions</p> Signup and view all the answers

    Which characteristic about chondrosarcoma is true?

    <p>They consist of cartilaginous matrix</p> Signup and view all the answers

    Chondrosarcomas are reported more frequently in small breeds than large breeds.

    <p>False</p> Signup and view all the answers

    What is a common effect of haemangiosarcoma in affected animals?

    <p>Multiple lytic lesions</p> Signup and view all the answers

    Chondrosarcomas may produce lytic lesions similar to __________.

    <p>osteosarcomas</p> Signup and view all the answers

    Which type of intervertebral disk disease is characterized by sudden onset?

    <p>Type I</p> Signup and view all the answers

    Spondylosis is characterized by the formation of osteophytes at the dorsal margins of vertebral bodies.

    <p>False</p> Signup and view all the answers

    What common condition is often seen in dogs that is related to the lumbar vertebrae?

    <p>spondylosis</p> Signup and view all the answers

    Inflammation of tendon sheaths accompanying synovial joint inflammation is known as __________.

    <p>tenosynovitis</p> Signup and view all the answers

    Match the following animal species with the type of vertebral condition they most frequently experience:

    <p>Bulls = Thoracolumbar spondylosis Pigs = Intervertebral disk disease Dogs = Lumbar spondylosis Cats = Cervical vertebral ankylosis</p> Signup and view all the answers

    What is the primary cause of infectious arthritis in young farmed livestock?

    <p>Neonatal bacteraemia</p> Signup and view all the answers

    Non-infectious arthritis is most commonly seen in larger livestock such as cattle and horses.

    <p>False</p> Signup and view all the answers

    What lesion is associated with degenerative joint disease (DJD)?

    <p>fibrillation</p> Signup and view all the answers

    Which of the following bacteria is commonly associated with polyarthritis in horses?

    <p>Escherichia coli</p> Signup and view all the answers

    True or False: Diskospondylitis is commonly caused by fungal infections.

    <p>False</p> Signup and view all the answers

    What is the predominant cause of bacterial arthritis in dogs?

    <p>Direct implantation of bacteria due to penetrating wounds.</p> Signup and view all the answers

    In young animals, the infection often spreads from the synovial membrane to the __________ due to their close vascular relationship.

    <p>bone</p> Signup and view all the answers

    Match the following bacteria with their associated conditions:

    <p>Streptococcus spp. = Polyarthritis in ruminants E coli = Polyarthritis in horses Erysipelothrix rhusiopathiae = Polyarthritis in sheep Mycoplasma bovis = Polyarthritis in cattle</p> Signup and view all the answers

    Which of the following statements correctly describes immune-mediated arthritis?

    <p>It may be a sequel to previous infection.</p> Signup and view all the answers

    True or False: The viscosity of normal synovial fluid is low.

    <p>False</p> Signup and view all the answers

    What condition can develop in conjunction with septic arthritis in young animals?

    <p>Osteomyelitis</p> Signup and view all the answers

    The __________ is the inflamed joint space filled with excess synovial fluid due to infection.

    <p>synovial membrane</p> Signup and view all the answers

    Which of these joints is most commonly affected by septic arthritis in larger animals?

    <p>Knee</p> Signup and view all the answers

    True or False: Immune-mediated arthritis is typically mono-arthritis.

    <p>False</p> Signup and view all the answers

    What is a typical clinical sign of joint infection in neonatal animals?

    <p>Heat, pain, swelling</p> Signup and view all the answers

    The presence of __________ in synovial fluid is indicative of inflammation.

    <p>neutrophils</p> Signup and view all the answers

    Match the animal species with their common bacterial arthritis causes:

    <p>Dogs = Staphylococcus aureus Cattle = Mycoplasma bovis Pigs = Streptococcus suis Sheep = Erysipelothrix rhusiopathiae</p> Signup and view all the answers

    What are synovial fossae primarily known for in cattle, horses, and pigs?

    <p>Non-articulating depressions</p> Signup and view all the answers

    Synovial fossae are always indicators of severe joint damage.

    <p>False</p> Signup and view all the answers

    What condition is characterized by the presence of significant numbers of neutrophils in the synovial fluid?

    <p>Purulent arthritis</p> Signup and view all the answers

    Fibrin clots in the joint fluid can become _________ within the synovial membrane.

    <p>lodged</p> Signup and view all the answers

    Match the types of arthritis to their characteristics:

    <p>Lymphocytic/plasmacytic synovitis = Chronic condition with lymphocyte and plasma cell infiltration Fibrinous arthritis = Less destructive, common inflammatory response Purulent arthritis = Characterized by a high number of neutrophils Fibrinopurulent arthritis = Exudate contains both fibrin and neutrophils</p> Signup and view all the answers

    What can be a consequence of severe fibrinous arthritis?

    <p>Ankylosis</p> Signup and view all the answers

    The presence of fibrin in synovial fluid indicates normal permeability of blood vessels.

    <p>False</p> Signup and view all the answers

    What is the major cell type infiltrating the synovial membrane in chronic stages of many forms of arthritis?

    <p>Lymphocytes or plasma cells</p> Signup and view all the answers

    Septic arthritis can result in degeneration of articular cartilage caused by _________ from neutrophils.

    <p>lysosomal enzymes</p> Signup and view all the answers

    Which of the following may allow for infection to enter the subchondral bone?

    <p>Incomplete resolution of septic arthritis</p> Signup and view all the answers

    Granulation tissue can predispose to ankylosis in affected joints.

    <p>True</p> Signup and view all the answers

    What is the typical appearance of synovial fluid in cases of purulent arthritis?

    <p>Thin and cloudy or resembling pus</p> Signup and view all the answers

    The ___________ classification of arthritis includes both fibrin and neutrophils.

    <p>fibrinopurulent</p> Signup and view all the answers

    Match the joint conditions to their descriptions:

    <p>Fibrinous arthritis = Typically less destructive Septic arthritis = More dangerous due to potential cartilage erosion Chronic arthritis = Marked by lymphocyte infiltration Pannus formation = Granulation tissue overgrowth leading to possible ankylosis</p> Signup and view all the answers

    What can cause an increased total protein concentration in joint fluid?

    <p>Presence of fibrinogen and immunoglobulins</p> Signup and view all the answers

    Neutrophils account for less than 5% of the cell population in normal synovial fluid.

    <p>True</p> Signup and view all the answers

    What type of cells may be present in increased numbers in joints following trauma?

    <p>Mononuclear cells</p> Signup and view all the answers

    The presence of ______ indicates erosion of articular cartilage has extended into subchondral bone.

    <p>osteoclasts</p> Signup and view all the answers

    Match the following joint conditions with their descriptions:

    <p>Septic arthritis = Commonly affects a single joint due to penetrating wounds in small animals. Immune-mediated arthritis = Affects multiple joints with neutrophils in small animals. Degenerative joint disease = May show normal cytology or moderate mononuclear cell increase. Histiocytic sarcoma = A locally aggressive tumor commonly occurring in certain dog breeds.</p> Signup and view all the answers

    What is a common characteristic of histiocytic sarcoma?

    <p>It frequently metastasizes to regional lymph nodes.</p> Signup and view all the answers

    Bacteria are commonly seen in synovial fluid samples from septic joints.

    <p>False</p> Signup and view all the answers

    What cytological feature may complicate the diagnosis of septic arthritis in small animals?

    <p>Presence of neutrophils without degenerative changes</p> Signup and view all the answers

    A benign but locally invasive tumor of joints is called ______.

    <p>synovial myxoma</p> Signup and view all the answers

    Match types of tumors with their characteristics:

    <p>Synovial myxoma = Benign but can invade bone. Synovial sarcoma = Malignant tumor with aggressive growth. Histiocytic sarcoma = Rapidly growing and aggressive, particularly in certain breeds. Myxosarcoma = Has the potential for metastasis.</p> Signup and view all the answers

    Which of the following may obscure cellular features in synovial fluid smears?

    <p>Thick GAG deposits</p> Signup and view all the answers

    Immune-mediated arthritis typically affects a single joint in small animals.

    <p>False</p> Signup and view all the answers

    What is the best initial treatment option for a limb affected by histiocytic sarcoma?

    <p>Amputation</p> Signup and view all the answers

    ______ is the primary component of the granular background in normal joint fluid slides.

    <p>Glycosaminoglycans</p> Signup and view all the answers

    Study Notes

    Response of Bone to Mechanical Forces

    • Bone tissue responds to mechanical forces and injury through processes like atrophy, hypertrophy, hyperplasia, metaplasia, neoplasia, degeneration, and necrosis.
    • Wolff's law states that bone is deposited where needed and resorbed where not under mechanical stress.
    • Immobilization during fracture repair increases resorption, leading to reduced bone strength and stiffness.
    • Rigid metal implants share mechanical loads with bone but can cause atrophy and reduced strength; their removal post-healing is recommended to prevent complications like osteosarcoma.

    Physeal Damage

    • Growing animals' physes are vulnerable to traumatic injuries, particularly in the distal radial physis.
    • Slipped epiphysis occurs when compressive or shearing forces cause complete separation at the growth plate, typically through the hypertrophic zone.
    • Prognosis for slipped epiphysis is good if blood supply to the epiphyseal vasculature remains intact.
    • Femoral head slipped epiphysis risks avascular necrosis, particularly in calves, foals, and puppies due to vascular damage.
    • Angular limb deformities arise from physeal fractures; valgus deformity results in lateral deviation and varus deformity in medial deviation.

    Fracture Repair

    • Fractures occur when bones are subjected to excessive mechanical forces or pre-existing diseases weakening them.
    • Initial fracture repair involves haematoma formation, leading to a cascade of inflammatory responses and new tissue formation.
    • The repair progresses through stages: haematoma and inflammation, callus formation, and remodeling to restore original bone shape.
    • Secondary healing features a callus composed mainly of hyaline cartilage, which transitions to woven bone through endochondral ossification.
    • Fracture callus size correlates with movement between fracture ends; rigid immobilization can lead to primary bone repair with minimal callus formation.

    Complications of Fracture Repair

    • Common complications (3 I's):
      • Infection can delay healing and lead to osteomyelitis if not controlled early.
      • Instability from excessive movement or soft tissue interference may result in pseudoarthrosis.
      • Inadequate blood supply due to necrotic bone fragments impairs healing and may require removal of sequestrae.

    Skeletal Dysplasias

    • Genetic abnormalities affecting bone formation or remodeling are classified as skeletal dysplasias, often presenting as short stature and bone fragility.
    • Environmental factors like toxins and nutritional deficiencies can cause skeletal abnormalities that mimic genetic defects.

    Chondrodysplasias

    • Characterized by disproportionate dwarfism, notably in breeds such as Dachshund and Basset Hound.
    • Bulldog chondrodysplasia affects miniature cattle breeds like Dexter and leads to severe skeletal deformities.
    • Spider Lamb syndrome in sheep results in disproportionate long limbs and various skeletal deformities.

    Nutritional Imbalances and Toxins

    • Severe malnutrition or starvation can lead to growth plate abnormalities and growth arrest lines due to retarded longitudinal bone growth.
    • Manganese deficiency affects cartilage formation, resulting in limb deformities in calves and lambs.
    • Copper deficiency impacts collagen cross-linking, increasing bone fragility and being linked to osteochondrosis.
    • Vitamin C deficiency disrupts collagen synthesis, leading to fragile bones, particularly in guinea pigs, resulting in sub-periosteal hemorrhages.
    • Certain plant species can have teratogenic effects, causing skeletal abnormalities during fetal development or influencing postnatal bone remodeling.### Nutritional Deficiencies and Their Effects
    • Starvation leads to growth arrest lines and serious atrophy of fat.
    • Manganese and zinc deficiency causes disproportionate dwarfism and enlarged joints.
    • Copper deficiency results in osteoporosis, fractures, and osteochondrosis.
    • Vitamin C deficiency is associated with subperiosteal hemorrhage and fractures.

    Congenital Skeletal Diseases in Farm Animals

    • Skeletal abnormalities represent a significant portion of congenital issues in lambs; one study found 52% of lamb abnormalities related to the skeletal system.
    • Deformities may be sporadic or outbreak-related and can stem from genetic, teratogenic factors, or nutritional deficiencies during gestation.
    • Accurate clinical history is crucial for distinguishing between genetic and non-genetic causes of abnormalities.
    • Chondrodysplastic dwarfism in cattle can be confused with nutritional deficiencies affecting bone growth; clinical features may not reveal the exact cause.
    • High incidence of skeletal diseases in newborns typically indicates non-genetic origins unless linked to a new dominant mutation.
    • Genetic disorders with recessive patterns affect only 25% of offspring from heterozygous parents.

    Teratogenic Effects and Nutritional Deficiencies

    • Early pregnancy drought conditions and inappropriate diets contribute to varying degrees of skeletal deformities.
    • Insults during embryogenesis are more detrimental, leading to significant developmental defects.
    • If nutritional deficiencies or teratogenic agents are identified, recovery may occur with a normal diet post-birth, contrasting with genetic causes.
    • Infection during pregnancy from teratogenic viruses can lead to widespread congenital abnormalities.

    Diagnostic Evaluation and Sample Collection

    • Comprehensive examination of affected animals is vital for understanding lesions.
    • Post-mortem examinations should focus on rapidly growing bones to assess conditions.
    • Radiography provides insight into bone structure but is not definitive in early osteoporosis detection.
    • Trace element status of affected animals aids in understanding underlying causes of skeletal abnormalities.

    Metabolic Bone Diseases

    • Metabolic bone diseases arise from imbalances in bone homeostasis and can be classified into rickets, osteomalacia, fibrous osteodystrophy, and osteoporosis.
    • Osteoporosis is characterized by a reduction in bone quantity without compromising bone quality.
    • Mild cases of osteoporosis may go undiagnosed; clinical signs often only emerge after fractures occur.
    • Nutritional deficiencies such as calcium can lead to osteoporosis, especially in young, growing animals.
    • Starvation impacts skeletons more in younger animals, leading to observable growth arrest lines.

    Rickets and Osteomalacia

    • Rickets affects developing skeletons in young animals while osteomalacia occurs in adults, both due to mineralization defects.
    • Primary aetiology includes dietary deficiencies of vitamin D and phosphorus.
    • Rickets is more prevalent in herding species like sheep; vitamin D deficiency can also affect housed animals.
    • Common lesions include stiffness, lameness, and observable abnormal bone growth patterns.

    Fibrous Osteodystrophy (FOD)

    • Characterized by extensive bone resorption leading to fibroplastic changes; linked to hyperparathyroidism.
    • Susceptibility varies among species; more common in pigs, dogs, and reptiles but rare in sheep and cattle.
    • Primary hyperparathyroidism arises from adenomas in the parathyroid glands but less common overall.
    • Persistent hypercalcemia associated with untreated primary hyperparathyroidism results in soft tissue mineralization.### Pseudohyperparathyroidism
    • Caused by tumors producing parathyroid-related hormone, notably malignant lymphoma and apocrine gland adenocarcinoma.
    • Bone lesions are typically mild and clinically/radiographically inconspicuous.

    Secondary Hyperparathyroidism

    • Most frequent cause of fibrous osteodystrophy; arises from chronic renal disease or calcium-phosphorus dietary imbalance.
    • PTH secretion increases due to decreased plasma ionized calcium, leading to generalized bone resorption.
    • Common in dogs, occasionally in cats, associated with chronic renal failure, especially in young animals with familial renal disease.

    Pathogenesis of Renal Secondary Hyperparathyroidism

    • Decreased glomerular filtration rate causes reduced phosphorus excretion ➔ increased serum phosphorus ➔ elevated FGF23 ➔ inhibits active vitamin D production ➔ decreased serum calcium ➔ stimulates PTH release ➔ activates osteoclasts ➔ osteoclastic bone resorption ➔ fibrous tissue and woven bone replace normal bone.

    Nutritional Secondary Hyperparathyroidism

    • Results from dietary calcium deficiency or excess phosphorus, leading to inverse relationship between calcium and phosphorus.
    • Pathogenesis involves low-normal dietary calcium and high-phosphorus intake ➔ increased serum phosphorus ➔ decreases serum calcium ➔ stimulates PTH release ➔ similar outcomes of osteoclastic resorption.

    Gross Lesions in Specific Animals

    • Horses and goats show bilateral skull swelling (“big-head”) due to high phosphorus diet, commonly grain-heavy.
    • Fibrous osteodystrophy in horses also associated with certain tropical grasses or oxalate-rich diets that impair calcium absorption.
    • Pigs and goats on unsupplemented grain diets may develop similar osteodystrophy.

    Osteoporosis and Rickets

    • Osteoporosis arises mainly from starvation or copper deficiency; characterized by porous bones with thinner cortices.
    • Rickets typically results from vitamin D or phosphorus deficiency; hallmark lesion is segmental thickening of the physis.

    Investigating Fracture Outbreaks

    • Often linked to metabolic bone diseases like osteoporosis, rickets, or osteogenesis imperfecta.
    • Post-mortem examinations with bone sampling critical for diagnosis; costochondral junctions are particularly informative.
    • Collect additional samples for serum Ca and P tests; dietary history plays a vital role.

    Legg-Calvé-Perthes Disease

    • Avascular necrosis of the femoral head primarily affects small dog breeds, especially miniature poodles.
    • Insidious onset occurs between 4-8 months of age; bilateral cases in 15% of instances.
    • Pathogenesis linked to ischemia from increased intra-articular pressure, leading to potential femoral head collapse.

    Bacterial Osteomyelitis

    • Common in young horses and ruminants, primarily from hematogenous routes and localized in metaphyses and epiphyses of long bones.
    • Clinical signs may develop months post-infection due to bone lesions causing pain and potential fractures.

    Common Bacterial Agents

    • Equine infections often involve Escherichia coli, Streptococcus spp, Klebsiella spp, and Rhodococcus equi.
    • Ruminants frequently see Salmonella spp and Trueperella pyogenes; dogs and cats less commonly affected but related to compound fractures.

    Vertebral Osteomyelitis/Diskospondylitis

    • Occurs due to hematogenous infections, often in neonates with inadequate passive immunity.
    • Can cause pathological fractures and neurological signs from spinal cord compression due to secondary infections.

    Mandibular Osteomyelitis

    • Primarily affects cattle (Actinomyces bovis), marked by a “honeycomb” appearance in jawbone.
    • Bacterial infection often follows prior tissue injury; osteomyelitis may also occur in other species.

    Tumours & Tumour-like Lesions

    • Bone tumors prevalent in dogs and lesser extent in cats, often arising from mesenchymal tissues.
    • Osteosarcoma is the most common primary bone tumor in dogs (80% of cases) and cats (70%).
    • Typically aggressive, with early metastasis to lungs; most frequent in large breeds. Common sites include distal radius, proximal humerus, and distal femur.

    Spondylosis

    • Common degenerative disease of the vertebral column characterized by osteophyte formation at vertebral margins.
    • Initial degeneration in the ventral annulus fibrosus may result from trauma, leading to displacement and ligament stretching.
    • Progression results in extensive osteophyte formation and bony bridging of intervertebral spaces.
    • Most frequently observed in bulls, pigs, and dogs, particularly in the thoracolumbar region for bulls and first two lumbar vertebrae for dogs.
    • Cats may experience cervical vertebral ankylosis linked to vitamin A toxicity.
    • Key lesions include fibrillation, eburnation, bone sclerosis, and joint capsule thickening.
    • Intervertebral disk disease is classified into type I (sudden, chondrodystrophic) and type II (slow, less severe, non-chondrodystrophic).

    Inflammatory Diseases of Joints

    • Arthritis or synovitis refers to inflammation of joints, often accompanied by tenosynovitis in adjacent tendon sheaths.
    • Infectious arthritis commonly occurs in livestock and young animals post-neonatal bacteraemia, while dogs and cats more often exhibit immune-mediated arthritis.
    • Non-articulating depressions known as synovial fossae are common in cattle, horses, and pigs; these are acquired postnatally and of minimal clinical significance.
    • Fibrinous arthritis indicates increased vascular permeability, often seen in bacterial infections; presence of fibrin in synovial fluid suggests acute inflammation.
    • Synovial fluid in fibrinous arthritis may be turbid and the synovial membrane can be hyperaemic with prominent villi.
    • Purulent arthritis is marked by high neutrophil counts and poses a risk of cartilage and joint structure destruction.
    • Erosive and non-erosive classifications exist for immune-mediated arthritis; both forms typically display extensive inflammation.

    Bacterial Arthritis

    • Commonly occurs in horses and ruminants as a result of neonatal conditions or infections in various body systems.
    • Infection in joints often co-occurs with osteomyelitis, especially in young animals, leading to polyarthritis.
    • Key bacteria involved include Streptococcus spp, E. coli, and Staphylococcus aureus, with Mycoplasma bovis emerging as a concern in cattle.
    • In dogs and cats, bacterial arthritis often follows direct implantation from penetrating wounds, usually monoarticular and associated with opportunistic bacterial infections.

    Diskospondylitis

    • Inflammation of intervertebral disks that can lead to contiguous vertebral osteomyelitis.
    • Typically bacterial in origin, especially following primary bacteraemia; fungi may be involved in canine cases.
    • Most prevalent in large male dogs, often in the lumbosacral spine.
    • Staphylococcus aureus is the predominant pathogen identified.

    Immune-mediated Arthritis

    • Classified as non-infectious inflammatory diseases in joints associated with antigen persistence or immune complex deposition.
    • Typically manifests as polyarthritis, more common in dogs and cats; distinguished as erosive or non-erosive forms.

    Synovial Fluid Assessment

    • Analysis reveals joint lesion causes and lesion duration; involves assessing color, turbidity, protein concentration, and total nucleated cell count.
    • Normal synovial fluid is typically clear and colorless, varying slightly in horses.
    • Viscosity is important for joint function; decreased viscosity often indicates disease involvement.
    • Increased protein concentration suggests inflammation due to fibrinogen and immunoglobulin effusion.
    • Cytological evaluation may reveal neutrophils, significant in differentiating between septic and immune-mediated arthritis.

    Tumours & Tumour-like Lesions of Joints

    • Tumours around joints arise from synovioblastic cells or supporting structures.
    • Histiocytic sarcoma is an aggressive canine tumour, particularly in flat-coated and golden retrievers; presents as soft tissue swellings and may metastasize.
    • Synovial myxoma, while benign, can invade bone and mimic malignancy on radiographs; misdiagnosis is possible without biopsy.
    • Differentiation between myxoma and myxosarcoma is crucial, with histology providing essential information for diagnosis.

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    Test your knowledge on Wolff's law and its implications for bone strength and healing. This quiz explores the effects of mechanical stress on bones, the consequences of rigid implants, and cellular responses in bone tissue. Match terms with their definitions to solidify your understanding of bone biology.

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