Hypocalcaemia

Question 1

What is hypocalcaemia

Answer 1

Serum calcium 2.2

Question 2

What causes hypocalcaemia (6)

Answer 2

Severe vitamin D deficiency (MOST COMMON)

Disruption of parathyroid gland due to total thyroidectomy.

Following selective parathyroidectomy

Mg2+ deficiency

Cytotoxic drug-induced hypocalcaemia (less common)

Pancreatitis, rhabdomyolysis and large volume blood tranfusions (less common)

Question 3

What can causes Mg2+ deficiency

Answer 3

Omeprazole
Diarrhoea
Alcohol abuse

Question 4

What are acute neuromuscular symptoms of Hypocalcaemia

Answer 4

Neuromuscular irritability (tetany) 
Paresthesia 
Twitvhing 
Carpopedal spasm 
Trousseu's sign 
Chovsteks sign

Question 5

What is Trosseau’s sign

Answer 5

Carpopedal spasm caused by inflating the blood-pressure cuff to a level above systolic pressure for 3 minutes.

Question 6

What is a Carpopedal spasm

Answer 6

Carpopedal spasms are frequent and involuntary muscle contractions in the hands and feet. They can be extremely painful

Question 7

What is Chovsteks sign

Answer 7

The twitching of the facial muscles in response to tapping over the area of the facial nerve

Question 8

What are acute cardiac symptoms of Hypocalcaemia

Answer 8

Prolonged QT
Hypotension
Papilloedema

Question 9

What are chronic symptoms of hypocalcaemia

Answer 9

ectopic calcificartion of basal ganglia
Extrapyramidal signs
Parkinsonism
Dementia

Question 10

What is the diagnositc test for hypocalcaemia

Answer 10

Check parathyroid hormone

Question 11

If PTH is normal or low what should be done

Answer 11

Check magnesium

Question 12

If PTH is high what should be done

Answer 12

Check Urea and Creatanine

Question 13

If urea and creatinine are high with hypocalcaemia what should be concluded

Answer 13

Renal failure

Question 14

If urea and creatinine are normal with hypocalcaemia what should be done

Answer 14

Check Vit D

Question 15

If magnesium is low with hypocalcaemia what should be concluded

Answer 15

Magnesium deficiecny

Question 16

If magnesium is high with hypocalcaemia what should be concluded

Answer 16

Hypoparathyroidism

Question 17

If urea and creatinine are normal and Vit D is high with hypocalcaemia what should be concluded

Answer 17

Pseudohypoparathyroidism or calcium deficiency

Question 18

If urea and creatinine are normal and Vit D is low with hypocalcaemia what should be concluded

Answer 18

vit D deficiency

Question 19

What are the 2 most common causes of hypoparathyroidism

Answer 19

Post surgical

Autoimmune

Question 20

What is pseudohypoparathyroidism

Answer 20

A rare condition. Target organs are unresponsive to PTH and so unlike hypoparathyroidism it results in high rather than low PTH concentrations

Question 21

What is the classic clinical feature of pseudohypoparathyroidism

Answer 21

Shortening of the 4th and 5th metacarpals

Question 22

What is treatment for mild hypocalcaemia

Answer 22

Commence oral calcium tablets

If post thyroidectomy
- Repeat calcium 24 hours later

If low Mg2+,
- Stop any precipitating drug and replace Mg2+

If vit D deficient

• Start vitamin D
• Advice regarding dietary sources
• Most tablets contain a combination of vitamin D and calcium
• Maintenance dose ~400- 1000 international unit

Question 23

What is treatment for severe hypocalcaemia

Answer 23

Administer IV calcium gluconate •

• Initial bolus (10-20ml 10% calcium gluconate in 50-100ml of 5% dextrose IV over 10 minutes with ECG monitoring)
• The initial bolus can be repeated until the patient is asymptomatic and/or calcium levels significantly increased
• A Calcium gluconate infusion can then follow (100ml of 10% calcium gluconate in 1litre of 0.9% saline or 5% dextrose and infuse at 50-100ml/h)