Flashcards in Bone physiology Deck (69)
True or False
One vertebral fracture will lead to another
What do osteoclasts do?
What do osteoblasts do?
Put down osteoid to form new bone
Who should be assessed using the risk factor assessment? (2)
Anyone over 50 with risk factors
Anyone under 50 with an early menopause or on steroids
When should a DEXA scan be requested?
10 year risk assessment of at least 10%
In a DEXA scan, which value is the most important?
What does the T value have to be to be classified as osteoporosis?
More than -2.5
What is a Z score?
Age matched so compares with age and size
When are Z scores used?
If younger than 20
What class of drug is given if osteoporosis is diagnosed?
What are examples of bisphosphonates?
Alendronic or risedronic acid
When is zolendronic acid given?
If DEXA intolerable
What is given in severe spinal osteoporosis?
If osteopenia is diagnosed what is done?
Lifestyle advice e.g. smoking, alcohol, weight bearing exercise, falls advice
True or False
Post-menopausal women should increase their dairy intake
How do bisphosphonates work?
Apoptosis of osteoclasts so inhibit bone resorption
What are long term potential side effects of bisphosphonates?
Osteonecrosis of jaw
How is zolendronic acid given?
Once yearly IV infusion
When is denosumab given?
If bisphosphonates intolerable.
How should alendeonic acid be given?
Tablet, 30 minutes before food and don't lie down for half an hour after
When should alendronic acid be stopped?
Oesophagitis or ulcers
What are common side effects of alendronic acid?
GI side effects
How does denosomuab work?
Monoclonal Ab that binds to RANKL
What is RANKL?
Receptor activator of nuclear factor kB ligand
How does activating RANKL prevent osteoporosis?
Inhibits osteoclasts and decreases bone resorption
How is denosomuab given?
Subcut injection 6 monthly
Why is strontium not recommended as 1st line?
Fracture reduction is slightly less and dangerous in heart disease
Where does Paget's disease affect?
What is Paget's disease?
Increased osteoclast activity with abnormalities. Reduced strength
What is a complication of Paget's disease?
What symptoms may present with Paget's?
Often asymptomatic but bone pain or deformity and deafness
How is Paget's diagnosed?
Increased alk phos
How is Paget's treated?
Which defect causes osteogenesis imperfecta?
What is associated with osteogenesis imperfecta?
Which receptor on the parathyroid is for calcium?
Ca sensitive receptor
What kind of receptor is CaSR?
G protein coupled
How is vitamin D stored in the liver?
What does the liver convert it to?
What does the kidney turn it into?
What are symptoms of acute hypercalcaemia?
What are symptoms of chronic hypercalcaemia?
What are major causes of hypercalcaemia?
What drugs can cause hypercalcaemia?
What will blood results be for 1o hyperparathyroidism?
Raised serum Ca
Raised serum PTH
Increased urine Ca excretion
What other serum protein is important for diagnosing malignancy?
Alkaline phosphate (raised in malignancy)
What is the treatment for acute hypercalcaemia?
Loop diuretics once rehydrated
Bisphosphonates will lower Ca
How is 1o primary hyperparathyroidism managed?
Surgery or nothing
When should surgery for 1o hyperparathyroidism be indicated?
If end organ damage e.g. renal stones, osteoporosis, gastric ulcers or renal disease
Or if calcium is v high (>2.85)
What is 2o hyperparathryoidism?
Physiological response to low Ca
What is 3o hyperparathyroidism?
Overactive PTH after many years of 2o
Which genetic syndromes are closely linked with hyperparathyroidism?
What is FHH?
Familial hypocalciuric hypocalcaemia
What signs will be present in FHH?
Low Ca urine
How does PTH work on the gut?
Causes it to absorb Ca and therefore increased serum Ca levels
In which fish is vitamin D high in?
What are the symptoms of hypocalcaemia?
Paraesthesia in extremities and perioral
tetany and cramps
Fatigue and myopathy
Long QT on ECG
What are the causes of hypocalcaemia?
Vitamin D deficiency
What is the treatment for acute hypocalcaemia?
10ml 10% IV calcium gluconate over 10 mins
In what congenital condition is the parathyroid gland underachieve?
What are the other features of DiGeorge syndrome?
What is the long term management of hypoparathyroidism?
Calcium supplement daily
Vitamin D tablet
Why can hypomagnaeseamia cause low calcium?
Ca release is Mg+ dependent
What causes hypomagnaeaemia ?
What is pseudohypoparathyroidism?
Genetic defect of GNAS1 which means that PTH is resisted
What are symptoms of pseudohypoparathyroidism?
Brachdactyly of 4th metacarpal
What is pseudo-pseudohypoparathyroidism?
Same but with normal Ca
What can cause rickets?
Chronic renal failure