Parathyroid gland and calcium Flashcards
where is there a ‘bank’ of calcium that can be released into the blood
bones
which gland does calcium work on
which receptor
parathyroid gland
calcium sensing receptor (CaSR)
stimulation of CaSR in the parathyroid gland from increased blood calcium results in
decreased PTH
what is PTH in low calcium
high
what is PTH in high calcium
low
high calcium = low PTH = high calcitonin = … (increased/decreased) osteoclast activity
what is the final effect on serum Ca
decreased osteoclasts
decreased blood Ca
where is calcitonin made/released from
parafollicular C cells
low calcium = high PTH = low calcitonin = …. (increased/decreased) osteoclast activity
what is the final effect on serum Ca
increased (want to chew up bone to release Ca)
increased blood Ca
effect of PTH on kidneys (2 - on calcium and phosphate)
increased calcium reabsorption (increase blood Ca bc PTH is high when Ca is low)
phosphate excretion
main cause of hypercalcaemia
hyperparathyroidism
aetiology of hypercalcaemia (4)
not including examples of h….parathyroidism
hyperparathyroidism
lung mets
familial hypocalciuric hypercalcaemia (FHH)
pagets
how does hyperparathyroidism cause hypercalcaemia
high PTH = increased osteoclasts = high blood Ca (low bone Ca)
what can hypercalcaemia cause in the kidneys
kidney stones
how does hypercalcaemia present in the bones (3)
osteoporosis
fractures
bone pain
(renal) stones, (abdo) groans, bones, psychic moans
hypercalcaemia
how does hypercalcaemia affect the brain
confusion
how do kidney stones present in a patient with hypercalcaemia (2)
thirst
polyuria
phosphate levels in hyperparathyroid hypercalcaemia
phosphate levels in bone pathology hypercalcaemia
low
high
treatment of hypercalcaemia (1 symptomatic and 1 curative)
symptomatic: fluids - bc theyre dehydrated
curative: bisphosphonates
aetiology of hypocalcaemia ()
not including examples of h…parathyroidism
vit D deficiency
chronic kidney disease (CKD)
hypoparathyroidism
how does CKD (chronic kidney disease) cause hypocalcaemia
kidneys normally reabsorb Ca when levels are low, but in kidney disease you just end up peeing it all out (no reabsorption ability) = hypocalcaemia
OR (i think this one is right, but have both in my notes lol)
in CKD = decreases Ca and phosphate excretion = loads of it in the blood = bind together to make calcium phosphate = hypocalcaemia (bc the calcium isnt on its own)
aetiology of hypoparathyroidism (5)
congenital absence of parathyroid gland (DiGeorge)
autoimmune destruction of parathyroid gland
parathyroid malignancy
pseudohypoparathyroidism
pseudopseudoparahypothyroidism
aetiology of hyperparathyroidism (4)
parathyroid adenoma
MEN1
MEN2a
MEN2b
low levels of which element can cause hypoparathyroidism = hypocalcaemia
low Mg
what is pseudohypoparathyroidism caused by
pathophysiology
genetics
PTH resistance = low Ca
buzzword for pseudohypoparathyroidism (u should probs be concerned about this)
4th metacarpal bradydactyly (shortening)
ha j ur fucked
what are PTH, Ca and phosphate in pseudohypoparaythyroidism (why its called pseudo…)
PTH high
Ca low
phosphate high
what are PTH, Ca and phosphate in pseudopseudohypoparathyroidism (think pseudo pseudo…)
PTH high
Ca normal
phosphate high
which congenital issue presents with no parathyroid gland
DiGeorge syndrome
hypocalcaemia
4th metacarpal bradydactyly
high PTH
high phosphate
pseudohypoparathyroidism
normal Ca
high PTH
high phosphate
pseudopseudohypoparathyroidism
how does vitamin D deficiency (Causing hypocalcaemia) present;
in adults
in kids
what does this look like
osteomalacia - in adults
rickets - in kids
‘bendy limbs’
waddling gait
what do you give in pregnancy to prevent vit D deficiency in new borns
healthy start vitamins
how does hypocalcaemia present on ECG
QT prolongation
how does hypocalcaemia present in muscles
weakness, cramps
what is chovsteks sign
what is it used for
taping over facial nerve = face twitches
hypocalcaemia
what is trousseau sign
what is it used for
spasm of muscle in hand/wrist with bp cuff on
hypocalcaemia
PTH, Ca, phosphate in hypocalcaemia
PTH low (if parathyroid cause, high if not)
Ca low
phosphate low
treatment of hypocalcaemia acutely
IV calcium (calcium gluconate)
treatment of hypocalcaemia chronically (2)
calcium supplements
vit D supplements
when is PTH high in hypocalcaemia
when not a parathyroid problem (its trying to compensate)
