Primary hyperparathyroidism

Question 1

What is primary hyperparathyroidism?

Answer 1

A condition caused by autonomous excess secretion of parathyroid hormone (PTH), resulting in hypercalcaemia

Question 2

What is the most common cause of hypercalcaemia in outpatients?

Answer 2

Primary hyperparathyroidism

Question 3

How is primary hyperparathyroidism most commonly detected?

Answer 3

Incidentally on routine blood tests showing raised serum calcium

Question 4

What proportion of primary hyperparathyroidism cases are caused by a solitary parathyroid adenoma?

Answer 4

Approximately 85%

Question 5

What are the causes of primary hyperparathyroidism and their approximate frequencies?

Answer 5

Solitary adenoma (85%), hyperplasia (10%), multiple adenomas (4%), parathyroid carcinoma (1%)

Question 6

What proportion of patients with primary hyperparathyroidism are asymptomatic at diagnosis?

Answer 6

Around 80%

Question 7

What classic mnemonic is used to remember symptoms of primary hyperparathyroidism?

Answer 7

“Bones, stones, abdominal groans, and psychic moans”

Question 8

What renal symptoms are seen in primary hyperparathyroidism?

Answer 8

Polyuria, polydipsia, renal stones

Question 9

What gastrointestinal symptoms are associated with primary hyperparathyroidism?

Answer 9

Anorexia, nausea, constipation, peptic ulcer disease, pancreatitis

Question 10

What neuropsychiatric features may occur in primary hyperparathyroidism?

Answer 10

Depression, low mood, cognitive changes (“psychic moans”)

Question 11

What musculoskeletal features are seen in primary hyperparathyroidism?

Answer 11

Bone pain, fragility fractures, osteitis fibrosa cystica

Question 12

What cardiovascular association is commonly seen with primary hyperparathyroidism?

Answer 12

Hypertension

Question 13

Which genetic syndromes are associated with primary hyperparathyroidism?

Answer 13

Multiple endocrine neoplasia type I and type II

Question 14

What calcium level is typically seen in primary hyperparathyroidism?

Answer 14

Raised serum calcium

Question 15

What phosphate level is typically seen in primary hyperparathyroidism?

Answer 15

Low serum phosphate

Question 16

What happens to PTH levels in primary hyperparathyroidism?

Answer 16

PTH is raised or inappropriately normal despite hypercalcaemia

Question 17

Why is a “normal” PTH abnormal in primary hyperparathyroidism?

Answer 17

Because PTH should be suppressed in the presence of high calcium

Question 18

What imaging modality is commonly used to localise a parathyroid adenoma?

Answer 18

Technetium-99m sestamibi (MIBI) subtraction scan

Question 19

What skull X-ray finding is classically associated with primary hyperparathyroidism?

Answer 19

Pepper-pot (salt-and-pepper) skull

Question 20

What bone pathology may be seen in severe or long-standing disease?

Answer 20

Osteitis fibrosa cystica

Question 21

What is the definitive treatment for primary hyperparathyroidism?

Answer 21

Total parathyroidectomy

Question 22

When can conservative management be considered in primary hyperparathyroidism?

Answer 22

If calcium is <0.25 mmol/L above the upper limit of normal, patient is >50 years, and there is no end-organ damage

Question 23

What medical therapy can be used in patients unsuitable for surgery?

Answer 23

Cinacalcet

Question 24

How does cinacalcet work?

Answer 24

It is a calcimimetic that allosterically activates the calcium-sensing receptor, reducing PTH secretion