Calcium and PTH disorders

Question 1

what is the body’s response to low serum calcium levels?

Answer 1

secrete PTH from the parathyroid glands

Question 2

what is the impact of high conc Calcitriol on the parathyroid glands

Answer 2

calcitriol will cause negative feedback of PTH release

Question 3

3 effects of Calcitriol (vitamin D3) ??

Answer 3

bone resorption
renal re-absorption
more absorption in gut

Question 4

what is calcidiol?

Answer 4

VD2 - inactive form of vitamin D. obtained in diet, or from conversion of calciferol in liver

Question 5

how is vitamin D3 made in the skin?

Answer 5

UV rays causes conversion of a cholesterol molecule –> Vitamin D3

Question 6

what type of cell are osteoclasts?

Answer 6

macrophages!!

Question 7

how do osteoclasts resorb bone?

Answer 7

they release HCl acid which frees up Calcium and phosphate into the blood

Question 8

what do osteoblasts do?

Answer 8

they build up bone – they give it minerals and collegen

Question 9

describe signs of acute hypercalcaemia

Answer 9

patient who is severely dehydrated (due to polyuria) causing confusion and thirst

Question 10

why do hyperCa patients get renal stones?

Answer 10

from continuous reabsorption of calcium in the nephrons

Question 11

what enzyme changes vitamin D2 –> active D3?

Answer 11

1-alpha-hydroxylase

Question 12

hypercalcaemia

• high?
• emergency?

Answer 12

over 3 mmol/ L

over 3,75 mmol / L

Question 13

hypercalcaemia with high PTH and high urinary excretion of Calcium?

Answer 13

primary or tertiary hyperparathyroidism (lots of retention)

Question 14

hypercalcaemia with high PTH and low urinary Ca excretion?

Answer 14

Familial Hypocalciuric hypercalcaemia (FHH)

Question 15

hypercalcaemia caused by CaSR mutation?

Answer 15

FHH - autosomal dominant muration

Question 16

hypercalcaemia with low PTH and high ALP levels?

Answer 16

Conditions causing increased bone turnover!!!

- Eg. metastasis, thyrotoxicosis

Question 17

hypercalcaemia with low PTH and low ALP levels? (3)

Answer 17

1. myeloma
2. Vitamin D excess - many causes
3. “Milk-Alkali”

Question 18

2 signs of hypercalcaemia not included in stones, moans etc?

Answer 18

1. hypertension

2. proximal myopathy

Question 19

example of an “abdominal groan”?

Answer 19

pancreatitis

Question 20

serum levels for hypocalcaemia?

Answer 20

less than 2.1 !!

Question 21

what is Chvostek sign for hypocalcaemia?

Answer 21

facial twitching induced by tapping the facial nerve (anterior to the ear)

Question 22

what is Trousseau sign for hypocalcaemia??

Answer 22

spasm of the forearm and hand induced by 3 minutes of a blood pressure cuff

Question 23

common signs of hypocalcaemia?

Answer 23

hands = paraesthesia
SOB = due to bronchospasm
Muscle cramps
Fitting

Question 24

what surgery is the #1 cause of hypocalcaemia?

Answer 24

post-surgical-hypoparathyroidism when part of gland is removed !!

Question 25

classic symptoms of hypomagnesium?

Answer 25

Tremor, poor coordination, muscle spasms, personality changes, and nystagmus. Complications may inc seizures / cardiac arrest..

Question 26

what is the cellular function of Mg?

Answer 26

to allow Calcium to be released from cells

Question 27

are levels of PTH low or high in pseudohypoparathyroidism?

Answer 27

they are HIGH : but the mutation causes resistance to PTH

Question 28

pseudohypoparathyroidism levels…
PTH = low / high ?
Calcium = low / high ?

Answer 28

PTH is high (because)

Ca is low

Question 29

what is the classic sign of pseudohypoparathyroidism in the hands?

Answer 29

shortened 4th and 5th fingers

Question 30

pseudohypoparathyroidism signs (type 1a)
fingers :
weight:
cognitive:

Answer 30

short 4th + 5th fingers
obese
learning disability

Question 31

what is pseudo-pseudo-hypoparathyroidism?

Answer 31

the phenotypical changes WITHOUT the biochemical markers (normal PTH and normal Ca)

Question 32

what does the GNAS1 mutation cause?

Answer 32

pseudo-parathyroidism

Question 33

susan has high PTH levels, low Ca but no symptoms - what is this?

Answer 33

This is pseudohypoparathyroidism type 1b !!