Metabolic bone disease Flashcards
What are some drugs to treat osteoporosis?
ANTI-RESPORPTIVE bisphosphonates denosumab - monoclonal antibody HRT ANABOLIC teriparatide - PTH analogue
What are some risk factors for fractures?
low trauma fracture inflammatory disease endocrine disease malabsorption low BMI immobility medication family history of hip fracture alcohol vit D deficiency
What is the T score?
standard deviation relating to normal young adult of same gender
under -2.5 = osteoporosis
What are some tests to find underlying causes of osteoporosis?
Ca, PTH, vit D serum and urine electrophoresis TSH coeliac antibody FBC, ESR sex hormones
What are some examples of bisphosphonates?
alendronate, risedonate, ibandronate, zoledronate
What are the triad of symptoms for Paget’s?
pain, deformity, fracture
What are the tests for paget’s?
XR, isotope scan, alkaline phsphatase
How would you treat Pagets?
Only if symptomatic
- bisphosphonates, alendronate
analgesia
What is osteomalacia?
softening of bones caused by impaired bone metabolism - normally caused by inadequate levels of phosphate, calcium and vit D
What are the symptoms of osteomalacia?
weakness, fatigue
bone pain
fractures
How would you treat osteomalacia?
high dose Vit D and calcium
What are the normal and abnormal levels of Vit D?
> 50 nmol/l
<25 deficient
- we all need 10 micrograms per day
Who is at risk of vit D deficiency?
no sunlight - housebound, dark skin, clothing
renal failure
anticonvulsants
What are some symptoms of hypercalcaemia?
polyuria, thirst, constipation, confusion
What tests would you do in hypercalcaemia and what would results mean?
U&E
PTH
- high = primary hyperparathyroidism
-low = hypercalcaemia
What is the emergency level of hypercalcaemia?
> 3 mmol/l
How would you treat hypercalcaemia?
0.9% Saline - 4-6l in 24 hr
IV bisphosphonates or steroids in extreme cases
How would you treat dangerous hypocalcaemia? What level is that?
<2
10mls 10% calcium gluconate
calcium gluconate infusion
What are causes of low magnesium?
High alcohol
diabetes
diuretics
chemo
What T score indicates osteopenia?
between -1 and -2.5
At what age is HRT no longer desirable as osteoporosis treatment?
over 60s
What age do you go onto bisphosphonate if on a steroid, regardless of bone density?
65 years old
What is a treatment for severe osteoporosis?
teraperitide
What happens to PTH when serum calcium starts to fall?
PTH goes up
What does PTH do?
increased bone turnover
increased renal absorption
increase calcium absorption in gut
How would you monitor osteoporosis?
BMD
T score: -1 normal
Z score
FRAX score - risk of serious fracture in next 10 years
Which 3 factors contribute to bone strength?
bone density
bone size
bone quality (turnover, mineralisation, architecture)
What happens in ankylosing spondylitis?
calcium line down spine
can lead ot severe kyphosis of thoracic and cervical spine
inflammation - erosive damage - repair - new bone formation
What is Paget’s disease?
increased bone turnover resulting in bone remodelling, enlargement, deformity and weakness
formation >resorption
What is hyperphosphataemic rickets?
X linked defect to phosphate transport in proximal tubule
= low serum phosphate, high urine phosphate
growth retardation, bowing of long bones, dental abscesses
What is fibrous dysplasia?
can be part of mcCune-Albright syndrome
fibrous tissue development
= swelling in jaw, gaps in teeth, weak fibrous bone tissue
What is osteopetrosis?
osteoclasts cannot resorb bone
= skeletal fragility with high bone density
What is tumoral calcinosis?
massive periarticular soft tissue deposition of calcium and phosphate (esp. upper body), causes chronic renal failure
What is osteogenic/tumour induced osteomalacia?
small bony or soft tissue tumours secrete FGF23 and cause hypophsophataemia
What is Beal’s arachnodactyly?
mutation in gene that builds fibrillin-2
= aortic enlargement, unable to extend joints, joints can be deformed
(similar to Marfan’s)
What is a pneumonic to remember the risk factors for osteoporosis?
SHATTERED
steroids, hyperparathyroid/hyperthyroid, age, thin, testosterone deficient, early menopause rheumatology/renal disease, eating poorly, vitamin D deficient
