Hypercalciemia

Question 1

What two conditions account for around 90% of cases of hypercalcaemia?

Answer 1

Primary hyperparathyroidism and malignancy

Question 2

What is the most common cause of hypercalcaemia in non-hospitalised patients?

Answer 2

Primary hyperparathyroidism

Question 3

What is the most common cause of hypercalcaemia in hospitalised patients?

Answer 3

Malignancy

Question 4

Why is measuring parathyroid hormone (PTH) the key investigation in hypercalcaemia?

Answer 4

It distinguishes PTH-mediated causes from non–PTH-mediated causes

Question 5

How does malignancy commonly cause hypercalcaemia?

Answer 5

Through PTH-related peptide secretion, bone metastases, or increased osteoclastic activity

Question 6

Which tumour commonly causes hypercalcaemia via PTHrP secretion?

Answer 6

Squamous cell carcinoma of the lung

Question 7

Why does multiple myeloma cause hypercalcaemia?

Answer 7

Myeloma cells release cytokines that increase osteoclastic bone resorption

Question 8

Which cytokines contribute to hypercalcaemia in myeloma?

Answer 8

IL-1 and tumour necrosis factor

Question 9

Which granulomatous disease commonly causes hypercalcaemia?

Answer 9

Sarcoidosis

Question 10

How do granulomatous diseases cause hypercalcaemia?

Answer 10

Increased extrarenal vitamin D activation leading to increased calcium absorption

Question 11

Which infections can cause hypercalcaemia via granuloma formation?

Answer 11

Tuberculosis and histoplasmosis

Question 12

How does vitamin D intoxication cause hypercalcaemia?

Answer 12

Excess intestinal calcium absorption

Question 13

Which endocrine disorders are associated with hypercalcaemia?

Answer 13

Acromegaly and thyrotoxicosis

Question 14

What is milk-alkali syndrome?

Answer 14

Hypercalcaemia caused by excessive intake of calcium and absorbable alkali

Question 15

Which diuretic class is associated with hypercalcaemia?

Answer 15

Thiazide diuretics

Question 16

How do thiazides cause hypercalcaemia?

Answer 16

They reduce renal calcium excretion

Question 17

Which over-the-counter medications can cause hypercalcaemia?

Answer 17

Calcium-containing antacids

Question 18

How does dehydration contribute to hypercalcaemia?

Answer 18

Reduced renal calcium excretion due to volume depletion

Question 19

Which adrenal condition is associated with hypercalcaemia?

Answer 19

Addison’s disease

Question 20

Why is calcium usually normal in Paget’s disease of bone?

Answer 20

Bone turnover is increased but balanced

Question 21

When can Paget’s disease lead to hypercalcaemia?

Answer 21

With prolonged immobilisation

Question 22

What is the first-line initial management of hypercalcaemia?

Answer 22

Rehydration with intravenous normal saline

Question 23

How much fluid is typically required in initial hypercalcaemia management?

Answer 23

Approximately 3–4 litres per day

Question 24

Why is rehydration important in hypercalcaemia?

Answer 24

It increases renal calcium excretion

Question 25

Which drugs are used after rehydration to lower calcium levels?

Answer 25

Bisphosphonates

Question 26

How long do bisphosphonates take to start working?

Answer 26

2–3 days

Question 27

When is the maximal effect of bisphosphonates seen?

Answer 27

Around 7 days

Question 28

Which drug lowers calcium more rapidly than bisphosphonates?

Answer 28

Calcitonin

Question 29

In which condition are steroids useful in treating hypercalcaemia?

Answer 29

Sarcoidosis

Question 30

When may loop diuretics be used in hypercalcaemia?

Answer 30

In patients who cannot tolerate aggressive fluid rehydration

Question 31

Why must loop diuretics be used cautiously in hypercalcaemia?

Answer 31

They can worsen volume depletion and electrolyte imbalance