Calcium metabolism and disorders

Question 1

what does vitamin d increase

Answer 1

calcium phosphorylation absorption from the gut

Question 2

main stimulus of PTH production

Answer 2

low ca2+

Question 3

main stimulus of calcitonin production

Answer 3

high ca2+

Question 4

calcitonin effects on bone

Answer 4

inhibits osteoclast resorption
thereby lowers ca and po4

Question 5

calcium sensing receptor

Answer 5

g protein coupled receptor that plays a role i regulation of extracellular calcium homeostasis

Question 6

hypercalcaemia features

Answer 6

bones
stones
abdominal groans
psychic moas

Question 7

chronic hypercalcaemia features

Answer 7

Myopathy
Fractures
Osteopaenia
Depression
Hypertension
Pancreatitis
DU
Renal calculi

Question 8

acute hypercalcaemia features

Answer 8

Thirst
Dehydration
Confusion
Polyuria

Question 9

causes of hypercalcaemia

Answer 9

primary hyperparathyroidism= main cause

2nd is malignancy

3rd is drugs

Drugs: Vit D, thiazides
Granulomatous Disease eg Sarcoid, TB
Familial Hypocalciuric Hypercalcaemia
High turnover: bedridden, thyrotoxic, Pagets
Others
Tertiary hyperparathyroidism

Question 10

what to think in supressed PTH

Answer 10

malignancy

Question 11

diagnosis of primary hyperparathyroidism

Answer 11

raised serum calcium
raised serum PTH
increased urine calcium excretion

Question 12

diagnosis of hypercalcaemia of malignancy

Answer 12

Raised calcium and alkaline phosphatase
X-ray, CT, MRI, PET
Isotope Bone Scan

Question 13

mechanisms of hypercalcaemia of malignancy

Answer 13

Metastatic Bone destruction
PTHrp from solid tumours
Osteoclast activating factors

Question 14

management of acute hypercalcaemia

Answer 14

0.9& saline

Consider loop diuretics once rehydrated- avoid thiazides
Bisphosphonates- single dose will lower Ca over 2-3d, maximum effect at 1 week
Steroids occasionally used e.g Pred 40-60mg/day for sarcoidosis

Question 15

calcium mimetic

Answer 15

tricks calcium sensing recpeotr into thinking lots of calcium there so suppresses pth = cinacalcet

Question 16

management of primary hyperparathyroidism if unfit for surgery

Answer 16

cinacalcet

Question 17

indications for parathyroidectomy

Answer 17

end organ disease
very high calcium >2.85
under 50
egfr <60

Question 18

Hypocalciuric Hypercalcaemia

Answer 18

elevated calcium in blood but low in urine
often due to inherited disorder

Question 19

management of acute hypocalcaemia

Answer 19

Emergency: IV calcium gluconate 10 ml, 10% over 10 mins (in 50ml saline or dextrose)

Infusion (10ml 10% in 100 ml infusate, at 50 ml/h)

Question 20

causes of hypomagnasaemia

Answer 20

Alcohol
Drugs
Thiazide
PPI
GI illness
Pancreatitis
Malabsorption

Question 21

pseudohypoparathyroidism

Answer 21

rare inherited disorder that results in the body’s inability to respond properly toparathyroid hormone (PTH), leading to abnormalities in calcium and phosphate levels