Osteoporosis, Pagets, Osteomalacia + Polymyalgia Flashcards
What are the features of osteosarcoma?
Associated with lifting of periosteum off bone producing Codman triangle
+ sunburst appearance on X ray
What is the cause of pseudogout + what is seen in the synovial fluid?
Due to deposition of calcium pyrophosphate dihydrate (CPPD)
Synovial fluid shows rhomboid crystals with weak birefringence under polarised light
Describe the features of achondroplasia
Mutation in fibroblast growth factor receptor 3 (FGFR3) leads to impaired cartilage proliferation
What are the key lab findings in osteomalacia + why?
Low calcium - due to low Vit D
Low phosphate
High PTH - to compensate for low Ca
High alkaline phosphatase - due to osteoblast hyperactivity
What is osteopetrosis?
Marble bone disease
Due to poor osteoclast function due to carbonic anhydrase II mutation
What is osteogenesis imperfecta?
Brittle bone disease
Congenital defect of bone formation - defect in synthesis of collagen
What is Paget’s disease of the bone?
Paramyxovirus infection of osteoclasts
Imbalance between osteoblasts + osteoclasts
Causes mosaic pattern of lamellar bone
What is osteoporosis?
Disease with low bone mass + structural deterioration of bone tissue
Increase in bone fragility
What are the characteristic osteoporotic fractures?
Wrist, spine, hip
What is a fragility fracture?
Fracture following a fall from standing height or less, or as a result of routine activities
What are the RF for osteoporosis?
o Female gender. o Increasing age. o Menopause. o Oral corticosteroids. o Smoking. o Alcohol. o Previous fragility fracture. o Rheumatological conditions, such as rheumatoid arthritis and other inflammatory arthropathies. o Parental history of hip fracture. o Body mass index of less than 18.5 kg/m2.
How is a fragility risk score calculated?
OFracture or FRAX online calculator
When should a DXA be offered?
> 50 w/ fragility fractures
<40 w/ major RF for fragility fractures
Vertebral or hip fractures
People at high risk from OFracture score
What is the T score?
Number of standard deviations below mean bone mineral density of young adults at peak bone mass
When should bisphosphonates be given in osteoporosis?
BMD T score of -2.5 or less
What is the management of osteoporosis?
HRT for women
Oral corticosteroids
Bisphosphonates
What is PMR?
Polymyalgia rheumatica
Chronic, systemic rheumatic inflammatory disease characterised by aching + morning stiffness in neck, shoulder + pelvic girdle
RF for PMR
Old age
Females
Northern europeans
Infections + winter
Complications of PMR
GCA
Complications of long term steroids
When should PMR be suspected?
> 50 y/o with:
Bilateral shoulder/ pelvic girdle aching >2 weeks
Morning stiffness
Evidence of acute phase response
More general symptoms eg fever, fatigue, anorexia, weight loss
What is the management of PMR?
Corticosteroids
Assessing risk of osteoporosis
What bones are most commonly affected by Pagets?
Pelvis Femur Lumbar spine Skull Tibia
What is the pathology of Pagets?
Affects osteoclasts - increase in number + size
Increases bone formation of poorer quality
Collagen fibres form mosaic pattern
What is seen macroscopically in Pagets?
Thickened shafts + deformities in long bones
Cysts + stress fractures
Localised softening called osteoporosis circumscripta
