Calcium Flashcards
How much calcium intake should a growing person have and someone with osteoporosis?
Growing - 750mg
Osteoporosis- 1500mg
How is calcium stored in bone?
Hydroxyapatite
What is released when hydroxyapatite is broken down?
Phosphate and calcium
Ways to measure calcium ?
Total ca in blood
Ionised ca - physiologically important
Ca adjusted for albumin - better reflection of ionised ca
Effect of calcium binding to proteins?
Acidosis decreases binding to proteins
Alkalosis increases binding to proteins
How to parathyroid hormone respond to decreased plasma calcium?
Increase PTH synthesis from parathyroid gland.
1) Ca reabsoprtion via kidney
2) osteoclast resorption of bone
3) 1,25(OH)D production in kidney = increased ca but absorption
Calcitonin deceases = PTH stimulation on osteoclasts
What’s the role of RANK L and OPG in bone turnover?
PTH = RANKL produced from osteoblast = RANKL binds RANK receptor to osteoclast = active osteoclast for bone resorption
OPG = RANKL binds instead of to RANK receptor = decreased active osteoclast
What stimulates osteoclastogenesis?
MCSF and RANK L
Symptoms of Hypercalcaemia?
Stones - kidney stones
Bones - bone pain
Groans - depression
S Abdominal overtones - nausea and sickness
Causes of Hypercalcaemia?
Primary hyperparathyroidism
Hypercalcaemia of malignancy
Iatrogenic (side effect from drugs)
Treatment of primary hyperparathyroidism?
Surgery only of parathyroid glands
Signs and symptoms of hypocalcaemia?
Weakness
Nausea
Cramping
Trousseau Sign
Chvostek sign
Causes for Hypercalcaemia of malignancy?
Tumours produce PTHrP = stimulates RANK L
Causes of hypocalcaemia?
Renal failure
Hypo parathyroidism
Vit D malabsorption pancreatitis
Causes of hypo parathyroidism?
Post op
Idiopathic
