Clcium homeostasis - hypocalcaemia Flashcards

1
Q

What are the acute clinical features of hypocalcaemia

A

Tetany
paraesthesia
seizures
Prolonged QT interval
hypotension
heart failure
arrythmia
papilloedema
chovstek’s sign
Trosseau’s sign

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2
Q

What are the chronic features of hypocalcaemia

A

Ectopic calcification
parkinsonism
dementia
dry skin

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3
Q

What is the serum calcium at which any lower causes symptoms of hypocalcaemia

A

1.9mmol/l

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4
Q

What is chovsteks sign

A

tap on patients zygomatic arch and will see twitching of the lip to spasm of all facial muscles depending on severity

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5
Q

What is Trosseaus’s sign

A

Spasm of the wrist and hand after inflating a sphygmomanometer on the arm

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6
Q

How does thyroid surgery affect calcium levels

A

Damage to the parathyroid glands can occur which can cause hypocalcaemia

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7
Q

What are causes of hypocalcaemia

A

Disruption of parathyroid glands in thyroid surgery
Severe vitamin D defficiency
Magnesium defficiency

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8
Q

which drug causes magnesium deficiency and what is magnesiums role in calcium in the plasma

A

PPI can cause low magnesium and magnesium interferes with PTH production

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9
Q

What examinations are done in hypocalcaemia

A

ECG
serum calcium
albumin
phosphate
PTH
U&Es
Vitamin D
magnesium

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10
Q

What is the most common cause of hypoparathyroidism

A

Post surgery hypoparathyroidism

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11
Q

What is pseudohypoparathyroidism

A

The hypoparathyroid gland is insensitive to PTH and unresponsive - cause hypocalcaemia and hyperphosphatemia

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12
Q

What is the difference in PTH between pseudohypoparathyroidism and hypoparathyroidism

A

Pseudohypoparathyroidism has increased PTH compared to decreased

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13
Q

What is the treatment for mild hypocalcaemia

A

Oral calcium tablets

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14
Q

What is mild hypocalcaeima

A

asymptomatic with serum calcium above 1.9mmol/l

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15
Q

what is the treatment for mild hypocalcaemia caused by low Vit D

A

Vit D replacement

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16
Q

What is the treatment for mild hypocalcaemia caused by low magnesium

A

stop any other precipitating drug and replace magnesium

17
Q

What is severe hypocalcaemia

A

Medical emergency -
symptomatic or serum calcium less than 1.9 mmol/litre

18
Q

What is the treatment of severe hypocalcaeima

A

IV calcium gluconate
initial bolus 10-20ml 10% calcium gluconate in 5% dextrose IV in 10 minutes while being monitored on ECG

Calcium gluconate infusion can then follow - 100ml of 10% calcium gluconate in 1 litre of saline or 5% dextrose

19
Q

Why should the hydroxylate derivitaves of vitamin D be prescrived to renal impairment patients with hypocalcaemia caused by low Vit D

A

Because the vit D needs to be hydroxylated by the kidney to it’s active form

20
Q

What are the hydroxylated derivatives of vit D

A

Alfacalcidol and calcitrol