SA Osteosarcoma and Bisphosphonates Flashcards
Where are the two most common sites of an appendicular osteosarcoma?
Distal radius
Proximal humerus
What is the aetiology of nutritional secondary hyperparathyroidism?
Diet high in phosphorus/low in calcium
What is the pathogenesis of nutritional secondary hyperparathyroidism?
If calcium in blood is low, this stimulates the release of parathyroid hormone to return Ca levels to normal.
Calcium reabsorbed from bone
Osteopenia/osteoporosis
Normal bone still produced and normal growth plate
What would you seen on the radiographs of an anima withnutritional secondary hyperparathyroidism?
Cortices thin
Normal growth plates
What is the pathogenesis of panosteitis?
Degeneration of intramedullary (IM) adipocytes
Intramedullary ossification
What is the most common signalment of metaphyseal osteopathy?
Large and giant breeds
Age 2-8 months
How would you diagnose metaphyseal osteopathy?
Sclerotic line immediately adjacent to normal physis
Radiolucent zone adjacent to sclerotic line
Soft tissue swelling
Periosteal new bone formation
Give two synonyms for hypertrophic osteopathy
Maries, hypertrophic pulmonary osteoarthropathy
What is the cause of rickets?
Diet deficient in Ca, P, Vitamin D/sunlight
What would you see on the imaging of an animal with rickets?
Widened cup shaped growth plates due to accumulation of unmineralised osteoid
What is physitis and where is it most commonly seen?
Enlargement of the physeal region of long bones in growing horses
Especially distal radius, tibia and metacarpus/metatarsus.
What would you seen on that radiograph of an animal with physitis?
Flaring of the metaphysis and epiphysis adjacent to the physis.
Irregularity of the physis and surrounding sclerosis
What do bisphosphonates do?
Reduce bone resorption
Inhibit osteocasts
What are the uses of bisphosphonates?
Bone tumours
Hypercalcaemia
Immune mediated haemolytic anaemia (IMHA)
Malignant histiocytosis
What is the differences between non-amino bisphosphonates and amino bisphosphonates?
Non-amino bisphosphonates: disrupt metabolsims of osteoclasts leading to apoptosis (death) of osteoclast
Amino bisphosphonates: Newer, better antiresorbtive properties, disrupts intracellular signalling leading to apoptosis (death) of osteoclast
