Hyperparathyroidism

Question 1

What normally stimulates PTH release?

Answer 1

Hypocalcaemia

Question 2

What is the action of PTH?

Answer 2

Raises blood calcium level by:

• increasing osteoclasts activity (reabsorbing calcium from bones)
• increasing calcium reabsorption from the gut + kidneys
• increasing vitamin D activity

Question 3

What is primary hyperparathyroidism?

Answer 3

Uncontrolled PTH release from a tumour of the parathyroid gland –> hypercalcaemia

Question 4

How is primary hyperparathyroidism treated?

Answer 4

Surgical removal of tumour

Question 5

What causes secondary hyperparathyroidism?

Answer 5

Insufficient vitamin D
or CKD
–> low absorption of calcium from intestines, kidneys + bones
–> hypocalcaemia –> increased PTH production

Question 6

What causes tertiary hyperparathyroidism?

Answer 6

When secondary hyperparathyroidism continues for too long –> hyperplasia of the glands –> persistent high PTH + hypercalcaemia when secondary cause is resolved

Question 7

How is tertiary hyperparathyroidism treated?

Answer 7

Surgical removal of part of the parathyroid tissue

Question 8

Summarise the PTH and calcium levels in primary, secondary and tertiary hyperparathyroidism

Answer 8

PTH high in all
Calcium high in primary and tertiary
Calcium low in secondary