Hypercalcaemia and primary hyperparathyroidism

Question 1

What is 40% of calcium bound to in the plasma

Answer 1

albumin

Question 2

What regulates the plasma concentration of free calcium

Answer 2

PTH and Vitamin D

Question 3

Where do the superior parathyroid glands develop from

Answer 3

the fourth branchial pouch

Question 4

Where do the inferior glands develop form

Answer 4

the 3rd branchial pouch

Question 5

Where does the thymus develop form

Answer 5

the 3rd pouch

Question 6

What stimulates the PTH release

Answer 6

a decrease in plasma free calcium levels

Question 7

What senses changes in plasma free calcium

Answer 7

a specific calcium-sensing receptor on the plasma membrane of the parathyroid cells

Question 8

How does PTH increase plasma calcium

Answer 8

by stimulating:
bone resorption
intestinal absorption of calcium
Renal reabsorption of calcium

Question 9

How do we obtain sources of vitamin D

Answer 9

diet and synthesis in the skin in the presence of UV light

Question 10

What are some of the causes of hypercalcaemia

Answer 10

Malignancy: local resorption of bone caused by metastases
Hyperparathyroidism
Hypervitaminosis D - excess vitamin D
Idiopathic

Question 11

What is the most common cause of hypercalcaemia in ambulatory patients

Answer 11

hyperparathyroidism

Question 12

What is familial hypocalciuric hypercalcaemia

Answer 12

an autosomal dominant disorder caused by inactivating mutations in the gene encoding the calcium sensing receptor on the parathyroid cells in the kidneys

Question 13

What are some less common causes of hypercalcaemia

Answer 13

drugs: lithium (increased secretion of PTH)
thiazide diuretics (lower urinary calcium excretion
Immobility: increased bone resorption
Milk-alkali syndrome - high intake of milk or calcium carbonate

Question 14

What causes primary hyperparathyroidism

Answer 14

Solitary adenoma
multiple adenomas or 4 gland hyperplasia
Parathyroid carcinoma (rare cause)

Question 15

What might primary hyperparathyroidism be associated with

Answer 15

MEN1

MEN 2

Question 16

How might patients present with primary hyperparathyroidism

Answer 16

Most asymptomatic 
some may have: 
nausea 
constipation 
polydipsia 
polyuria 
depression 
generalised aches and pain (bones, stones, abdominal moans and groans)

Question 17

What is a common feature of primary hyperparathyrodism

Answer 17

Osteoporosis

Question 18

What needs to measured in patients with suspected primary hyperparathyroidism

Answer 18

phosphate levels - they may be low or low-normal

Question 19

What conditions should be excluded in patients with suppressed PTH

Answer 19

myeloma
malignancy
granulomatous conditions e.g. TB sarcoidosis and lymphoma

Question 20

What type of imaging should be performed in patients with confirmed primary hyperparathyroidism

Answer 20

renal US to look for renal calculi

Question 21

What is the only curative treatment for primary hyperparathyroidism

Answer 21

surgery

Question 22

What are the indications for surgery for primary hyperparathyroidism

Answer 22

symptomatic patients

asymptomatic patients with:

Question 23

Why might a total parathyroidiectomy be performed in patients with MEN1

Answer 23

High recurrence rate

Question 24

What should be given to patients with primary hyperparathyroidism with osteopenia or osteoporosis who are not candidates for surgery

Answer 24

bosphosphonates

Question 25

What is the most common cause of hypercalcaemia among hospitalised patients

Answer 25

malignancy