hypercalcaemia

Question 1

high levels of intracellular calcium causes

Answer 1

the cell to die

Question 2

calcium sensing receptor

Answer 2

controls amount of parathyroid hormone in the parathyroid gland
gets the kidneys to reabsorb calcium so it isnt lost to urine, and gets the bones to release Ca

Question 3

albumin in acidosis

Answer 3

gains H ions and becomes positively charged - starts to repel calcium
decreases bound calcium and increases proportion of free ionised calcium in the blood
total levels of calcium will still be the same
may lead to symptoms of hypercalcaemia

Question 4

hyperalbuminaemia

Answer 4

causes there to be a higher proportion of protein bound calcium
free ionised calcium levels will stay the same due to hormonal regulation compensation
pseudo/false hypercalcaemia
since the concentration of free ionised calcium stays the same

Question 5

true hypercalcaemia is caused by

Answer 5

1. osteoclastic bone resorption (most common cause)
   osteoclasts break down bone and release calcium into the blood
2. malignant tumours releasing parathyroid related protein which mimics parathyroid hormone and stimulates osteoclasts (also some tumours kill osteoblasts)
3. excess vit D
4. some medications eg. thiazide diuretics

Question 6

how does excess vit D cause hypercalcaemia

Answer 6

excess absorption in the gut

Question 7

why do thiazide diuretics cause hypercalcaemia

Answer 7

increase resoprtion in the distal tubule of the kidney

Question 8

consequences of high levels of ionised calcium

Answer 8

resting state of sodium channels is stabilised by calcium in neurons
high levels of extracellular calcium means voltage gated ion channels are lee likely to open and the neuron is less excitable (harder to depolarise)
causes slower or absent reflexes
slow muscle contraction causing constipation and muscle weakness
confusion hallucinations and stupor

Question 9

renal symptoms of hypercalcaemia

Answer 9

hypercalciuria leading to loss of excess fluid in kidneys and dehydration
combination of dehydration and hypercalciuria in the kidney can lead to calcium oxalate kidney stones

Question 10

hypercalcaemia on ECG

Answer 10

osborn wave
short QT interval
bradycardia
AV block

Question 11

lab tests

Answer 11

parathyroid hormone
vit D
albumin
phosphorous
magnesium levels

Question 12

treatment

Answer 12

1. increase urinary excretion - rehydrate individual causing more calcium to be filtered out
   lood diuretics - inhibit calcium reabsortioon in the loop of henle
2. increase GI excretion - use glucocorticoids to decrease calcium absortion
3. prevent bone resorption using bisphosphonates or calcitonin to inhibit osteoclasts

Question 13

types of PTH mediated hypercalcaemia

Answer 13

primary hyperparathyroidism - parathyroid adenoma or hyperplasia
tertiary hyperparathyroidism - renal failure
familial hypocalciuric hypercalcaemia
medications - lithium

Question 14

types of non-PTH mediated hypercalcaemia

Answer 14

hypercalcaemia of malignancy - paraneoplasstic production of PTHrP, osteolytc metastases, paraneoplastic production of vit D
granulomatous dssorders eg. sarcoidosis
medications
thyrotoxicosis
long periods of immmobilisaation
malk-alkali syndrome
adrenal insifficiency

Question 15

which medications cause PTH mediated hyperglycaemia

Answer 15

thiazide diuretics reduce renal calcium excretion
excess vitamin D increases intestiinal calcium absorption
clacium suppliments and antacids
vitamin A and vit A derivatives

Question 16

why do long periods of immobilisation cause hypercalcaemia

Answer 16

osteoclast activation due to lack of weight bearing activity.
usually in patients with high bone turnover at baseline

Question 17

symptomatic hypercalcaemia

Answer 17

usually develops acutely and is typically caused by excessive osteoclast medicated bone resporption, usually in association with malignancy

Question 18

clinical presentation of hypercalcaemia

Answer 18

nephrolithiasis
bone pain
constipation.
abdo pain
nausea and vomiting
anorexia
peptic ulder disease
pancreatitis
neuropsychiatric symptoms
diminished muscle exciteability
polyuria and dehydratiion

Question 19

pathopneumonic presentation of hypercalcaemia

Answer 19

stones - nephrolithiasis
bones - bone pain
thrones - increased urinary. frequency
groans - abdominal. pain, nausea, vomiting.
psychiatric overtones - anxiety, depression, fatigue

Question 20

how to confirm true hypercalcaemia

Answer 20

measure ionised calcium
calculate corrected calcium using total calcium and. serum albimun

Question 21

phosphate in hypercalcaemia

Answer 21

typically low due to inhibition of reabsorption renally

Question 22

calcium measurement in the setting of major acid base imbalance

Answer 22

corrected calcium concentration may not be accurate
recommended to use ionised calcium

Question 23

treating severe hypercalcaemia

Answer 23

IV fluid therapy
calcitonin, bisphosphonates, denosumab
treat arythmias or nephrolithiasis