Hyper/Hypo - Parathyroidism

Question 1

What are the causes of primary hyperparathyroidism?

Answer 1

1. Solitary adenoma (80%)
2. Hyperplasia of all glands
3. Parathyroid cancer

Question 2

What is the presentation of primary hyperparathyroidism?

Answer 2

• Patients report no symptoms (but not asymptomatic)
  1. Hypercalcaemia symptoms

2. Bone resorption symptoms
   - Pain
   - Fractures
   - Osteopenia/osteoporosis
3. Raised BP
   - Check everyone with hypertension for raised calcium

Question 3

What investigations would you undertake in primary hyperparathyoidism?

Answer 3

Bloods -

• Raised calcium and PTH
• Low phosphates
• Raised ALP from bone activity

Imaging -
- Raised 24hr urine Calcium (excludes familial hypocalciuric hypercalcaemia)

Other -

• DEXA scan for osteoporosis
• US scan to localise adenoma pre-op
• Technetium scan pre op

Question 4

What is the treatment for mild primary hyperparathyroidism?

Answer 4

• Increased fluid to prevent stones
• Avoid thiazides
• Avoid high calcium and vit D intake

Question 5

What is the indications for surgical management of primary hyperparathyroidism?

Answer 5

• High serum or urinary Ca2+
• Bone disease
• Osteoporosis
• Renal calculi
• Decreased renal function
• Age less than 50

Question 6

What is the definitive treatment for primary hyperparathyroidism?

Answer 6

• Excision of the adenoma or all four hyperplastic glands

Question 7

What are the complications of parathyroid surgery?

Answer 7

• Hypoparathyroidism
• Recurrent laryngeal nerve damage (hoarse voice)
• Symptomatic hypocalcaemia (hungry bones syndrome)
• Recurrence of adenoma

Question 8

What is cinacalcet?

Answer 8

• A calcimimetic
• Increases sensitivity of parathyroid cells to calcium which decreases PTH secretion
• Side effects - myalgia, low testosterone

Question 9

What are the causes of secondary hyperparathyroidism?

Answer 9

1. Vitamin D deficiency

2. Chronic renal failure

Question 10

What do blood results show in secondary hyperparathyroidism?

Answer 10

• Low Ca2+

- Raised PTH

Question 11

What is the treatment for secondary hyperparathyroidism?

Answer 11

• Correct causes
• Phosphate binders (lowers phosphate)
• Vitamin D
• Cinacalcet if PTH high and parathyroidectomy tricky

Question 12

What is tertiary hyperparathyroidism?

Answer 12

• Raised calcium with inappropriately raised PTH

Question 13

When does tertiary hyperparathyroidism occur?

Answer 13

• Occurs after prolonged secondary hyperparathyroidism, causing glands to have undergone hyperplastic or adenomatous change
• Causes raised calcium from very increased secretion of PTH unable to undergo negative feedback
• Seen in chronic renal failure

Question 14

What is malignant hyperparathyroidism?

Answer 14

• PTHrP is produced from squamous cell lung cancers, breast and renal cell carcinomas
• It mimics PTH resulting in raised calcium
• Actual PTH tests as low as PTHrP is not detected in the assay

Question 15

What is the cause of primary hypoparathyroidism?

Answer 15

• PTH secretion is low due to gland failure
  1. Autoimmune
  2. Congenital (Di George syndrome)

Question 16

What will blood results show in primary hypoparathyroidism?

Answer 16

• Low serum calcium
• Raised serum phosphate or normal
• Normal ALP

Question 17

What is the treatment for hypoparathyroidism?

Answer 17

• Calcium supplements

- Calcitriol or synthetic PTH (prevents hypercalciuria)

Question 18

What are the causes of secondary hypoparathyroidism?

Answer 18

• Radiation
• Surgery (thyroidectomy, parathyroidectomy)
• Hypomagnesia (needed for PTH secretion)

Question 19

What is pseudohypoparathyroidism?

Answer 19

• Failure of target cell response to PTH

- Patient will have short 4th and 5th metacarpals, round face, short stature, low IQ, calcified basal ganglia