Calcium and Bone disorders Flashcards
what is responsible for absorbing calcium and how do we obtain it
Vit D - skin and diet
what converts Vit D into it’s active form
kidneys and liver
what is the active form of Vit D and what effect does it have on calcium
calcitrol - increases Ca absorption in gut and prevents Ca loss in kidneys
what receptors detect calcium levels and where are they in the body
CaSR receptors in parathyroid
what does low levels of serum Ca causes the parathyroid to release
PTH
what effect does PTH have on the body (Vit D, phosphate and Ca)
stimulates Vit D, promotes phosphate excretion, increases Ca, absorption from intestines, reduces Ca absorption into bones (can lead to weak bones)
what opposes PTH and where is it produced
calcitonin from thyroid causes increases bone Ca absorption
what can cause hypercalcaemia (6)
primary hyperthyroid, primary hyperparathyroidism, kidney failure, cancer (breast and lung), drugs (Vit D and thiazides), granulomatous (TB and sarcoid)
what symptoms are seen with Hypercalcaemia
bones, stones, abdo groans and psychic moans: kidney stones, thist, dehydration, fractures, depression, myopathy, pancreatitis
how do you treat Hypercalcaemia (5)
fluids, loop diuretics, bisphosphonates, calcitonin, steroids
what are symptoms of hyperparathyroidism
fatigue, muscle weakness and aches, polyuria and thirst, bone pain and breaks, kidney stones, cardiac arrhythmias
what can cause primary hyperparathyroidism
adenoma, carcinoma or hyperplasia in parathyroid
what happens to PTH, Ca and ALP in primary hyperparathyroidism
raised serum Ca, PTH and ALP (increased Ca in urine)
how do you treat primary primary hyperparathyroidism
remove surgically
what causes secondary hyperparathyroidism
chronic renal failure, vit D deficiency
what happens to PTH and Ca in secondary hyperparathyroidism
high PTH, low/ normal calcium
how do you treat secondary hyperparathyroidism
treat underlying: kidney transplant/ Vit D supplements
what causes tertiary hyperparathyroidism
overactivity –> hyperplasia
what happens to PTH and Ca in tertiary hyperparathyroidism
high PTH and high Ca
how do you treat tertiary hyperparathyroidism and why in this way
parathyroidectomy - end organ damage and very high Ca levels
what investigations are done for hyperparathyroidism
biochem: Ca, PTH, ALP / imaging: X ray, CT, bone scan, sestamibi scan
what medications can be given for hyperparathyroidism
Vit D, cincaalcet, Bisphosphates, HRT
what can cause hypocalcaemia (5)
hypoparathyroidism, vit D deficiency, chronic renal failure, Vit D def, chronic renal failure, hyperabluminaemia, stress/ exercise
what are symptoms of hypocalcaemia
paraesthesia/ tingling in toes + fingers, muscle spasms, depression, hallucinations, seizures, slow HR, chovstek sign (facial twitch)
how do you treat hypocalcaemia
acute: IV calcium gluconate, chronic: calcium + Vit D supplements
what can cause hypoparathyroidism (5)
congenital absence eg DiGeorge, injury to parathyroid, autoimmune, hypomagnaesia, idiopathic
how do you diagnose hypoparathyroidism
biochem: low Ca and PTH, high phosphate, symptoms similar to hypocalcaemia
what is pseudohypoparathyroidism
resistance to PTH by receptors leading to hypocalcaemia
what gene is associated with pseudohypoparathyroidism
GNAS1
what hormone deficiency can cause osteoporosis in women
oestrogen in post menopause (see MSK)
what can lack of Vit D cause
osteomalacia and rickets (see MSK)
