General - Calcium

Question 1

Hypercalcaemia is considered when the corrected calcium is higher than what?

Answer 1

2.65mmol/L

Question 2

1) Name 4 causes of hypercalcaemia
2) What is the commonest cause of hypercalcaemia in hospitalised patients?
3) What is the commonest cause of hypercalcaemia in non-hospitalised patients?
4) What is the commonest ECG finding in a patient with hypercalcaemia?

Answer 2

1) Primary hyperparathyroidism, malignancy, tertiary hyperparathyroidism, end stage renal failure, osteolytic bone lesions, humoral hypercalcaemia, granulomatous disease i.e. tuberculosis and sarcoidosis, vitamin D and A intoxication, drugs such as thiazides and lithium, thyrotoxicosis, milk-alkali syndrome, familial hypocalciuric hypercalcaemia, acromegaly, Addison’s disease
2) Malignancy
3) Primary hyperparathyroidism
4) Short QT interval

Question 3

1) Name 2 reason why IV fluids would be a part of the management of hypercalcaemia
2) Why may bisphosphonates be useful in the management of hypercalcaemia?

Answer 3

1) Correct dehydration, protect the kidneys and increase calcium excretion
2) They inhibit osteoclast activity reducing calcium release

Question 4

Hypocalcaemia is considered when the corrected calcium is lower than what?

Answer 4

2.1mmol/L

Question 5

Name 4 causes of hypocalcemia

Answer 5

• Vitamin D deficiency (malnutrition, malabsorption, CKD)
• Hypoparathyroidism (post-parathyroidectomy, inherited hypoparathyroidism, pseudohypoparathyroidism)
• Hyperphosphatemia (tumour lysis syndrome, rhabdomyolysis, phosphate administration)
• Acute pancreatitis
• Hypomagnesaemia
• Acute alkalosis

Question 6

Features of hypocalcemia can be remembered by the mnemonic SPASMODIC - what do each of these letters stand for?

Answer 6

S – Spasms (Trousseau’s sign – involuntary contraction of the muscles in the hand and wrist that occurs after the compression of the upper arm with a blood pressure cuff)
P – Perioral paraesthesia (mouth numbness)
A – Anxiety/Irritability
S – Seizures
M – Muscle tone increase
O– Orientation impairment (i.e. confusion)
D – Dermatitis
I – Impetigo herpetiformis (inflammatory skin condition)
C – Chvostek’s sign (twitch of the facial muscles that occurs when gently tapping an individual’s cheek in front of the ear)

Question 7

1) How is mild hypocalcaemia managed?
2) How is severe hypocalcaemia managed?

Answer 7

1) Oral calcium supplement
2) IV calcium gluconate repeated as needed