Hyperparathyroidisim

Question 1

What are the key features of primary hyperparathyroidism on blood test?

Answer 1

HIGH calcium
Low phosphate
Normal PTH

Question 2

What is the cause of primary HPT?

Answer 2

Parathyroid gland adenoma, carcinoma or hyperplasia of all 4 glands. It is definitely managed with parathyroidectomy.

Question 3

What are the key features of secondary hyperparathyroidism on blood test?

Answer 3

Low calcium
HIGH phosphate
HIGH PTH

Question 4

What is the cause for secondary hyperparathyoridism?

Answer 4

Strongly associated with CKD but occurs due to:
Vitamin D deficiency, loss of calcium, calcium malnutrition/malabsorption
Abnromal pTH activity

Managed with vitamin D supplementation or phosphate binders

Question 5

What are the key features of tertiary hyperparathyroidism on blood test?

Answer 5

HIGH calcium
Low normal phosphate
HIGH pTH

Question 6

What is the cause of tertiary hyperparathyroidism?

Answer 6

Most common cause is Chiron kidney disease, even after kidney transplants
Excess PTH secretion When secondary hyperparathyroidism is untreated for too long

Question 7

How is tertiary hyperparathyoridism managed?

Answer 7

Cinacalcet which reduces PTH secretion and mimics actio of calcium on tissues

Parathyroidectomy

Question 8

How does pseudohyperparathyoriim present?

Answer 8

Symptoms of hypocalcaemia lie unexplained muscle cramps and tingling tensation and Chvostek’s and Trousseau’s sign, HOWEVER PTH is high

Question 9

What is the cause of pseudohypoparathyoridism?

Answer 9

Genetic disorder affecting GNAS1 gene

Question 10

What are the key features on diagnosic tests for pseudohypoparathyoridism?

Answer 10

Hypocalcaemia
Normal or elevated PTH

Question 11

What it’s he management of pseudohypoparathyoridism?

Answer 11

Calcium and Vitamin D supplementation

Question 12

How to distinguish between pseudohypoparathyoridism and CKD?

Answer 12

Same biochemical results but pseudohypoparathyoridism is a genetic condition presenting early in life

Question 13

What is the most common cause of primary hyperparathyroidism?

Answer 13

Solitary adenoma (85%)

Other causes include hyperplasia (10%), multiple adenoma (4%), and carcinoma (1%).

Question 14

What percentage of patients with primary hyperparathyroidism are asymptomatic?

Answer 14

Around 80%

These patients are often diagnosed through routine blood tests.

Question 15

What mnemonic can help remember the symptomatic features of primary hyperparathyroidism?

Answer 15

‘bones, stones, abdominal groans and psychic moans’

This includes symptoms like polydipsia, polyuria, depression, anorexia, nausea, constipation, peptic ulceration, pancreatitis, bone pain/fracture, renal stones, and hypertension.

Question 16

What are the key symptomatic features of primary hyperparathyroidism?

Answer 16

• Polydipsia
• Polyuria
• Depression
• Anorexia
• Nausea
• Constipation
• Peptic ulceration
• Pancreatitis
• Bone pain/fracture
• Renal stones
• Hypertension

These features can be remembered using the mnemonic: ‘bones, stones, abdominal groans and psychic moans’.

Question 17

What associations are commonly linked with primary hyperparathyroidism?

Answer 17

• Hypertension
• Multiple endocrine neoplasia: MEN I and II

These associations are important in the context of diagnosing and managing the disease.

Question 18

What are the characteristic X-ray findings in primary hyperparathyroidism?

Answer 18

• Pepperpot skull
• Osteitis fibrosa cystica

These findings are indicative of bone changes due to increased parathyroid hormone levels.

Question 19

What treatment is available for patients with primary hyperparathyroidism who are not suitable for surgery?

Answer 19

Cinacalcet

Cinacalcet is a calcimimetic that mimics the action of calcium on tissues.

Question 20

What is the mechanism of action of a calcimimetic like cinacalcet?

Answer 20

Allosteric activation of the calcium-sensing receptor

This mimics the action of calcium on tissues.

Question 21

What is the role of PTH at the bone?

Answer 21

Increases the activity of osteoclastic cells for bone resorption

This leads to the release of calcium and phosphate into the bloodstream.

Question 22

What happens to calcium and phosphate stores in the bone when PTH acts?

Answer 22

They are released into the bloodstream

This process is facilitated by the activity of osteoclastic cells.

Question 23

What are the two actions of PTH at the kidney?

Answer 23

• Increases hydroxylation and activation of vitamin D in the proximal convoluted tubules
• Increases calcium reabsorption from distal convoluted tubules and phosphate excretion

Question 24

What is PTHrp?

Answer 24

A polypeptide with a similar structure to PTH

Its name ‘related peptide’ reflects this similarity.

Question 25

From which type of cancer cells can PTHrp be secreted?

Answer 25

Squamous cell bronchial carcinoma ## Footnote This secretion can lead to hypercalcaemia.

Question 26

True or False: PTHrp can activate vitamin D.

Answer 26

False ## Footnote Unlike PTH, PTHrp cannot activate vitamin D.

Question 27

Fill in the blank: PTH increases the activity of _______ cells in the bone.

Answer 27

osteoclastic

Question 28

What effect does PTH have on phosphate excretion?

Answer 28

Increases phosphate excretion from the kidneys ## Footnote This occurs alongside increased calcium reabsorption.

Question 29

What is the primary effect of PTH on calcium levels in the bloodstream?

Answer 29

Increases calcium levels ## Footnote This is achieved through bone resorption and renal reabsorption.