hypocalcaemia

Question 1

Aetiology of hypocalcaemia (4)

Answer 1

• CKD (due to decreased Vit D activation)
• Severe Vit D deficiency
• Primary hypoparathyroidism
• Acute pancreatitis

Question 2

Drugs that can cause hypocalcaemia (4)

Answer 2

• Bisphosphonates
• Phenytoin
• Loop diuretics
• Cinacalcet

Question 3

ECG in hypocalcaemia

Answer 3

Longer QTc and ST segment

Question 4

How does hypocalcaemia affect muscle?

Answer 4

Muscle spasms: hands, feet, larynx, premature labour

Question 5

How does hypocalcaemia affect PTH? (2)

Answer 5

• Always increases
• Except in hypoparathyroidism

Question 6

How to calculate corrected calcium levels

Answer 6

CorrectedCalcium(mg/dL) = MeasuredCalcium(mg/dL)+[0.8×(4.0−Albumin(g/dL))]

Question 7

Symptoms/Signs of hypocalcaemia and hypoparathyroidism (4)

Answer 7

• Parasthesia - pins and needles
• Tetany (involuntary muscle contractions)
• Chvostek sign
• Trousseau sign

seizures
basal ganglia calcification
cataracts
ECG abnormalities

Question 8

Why may serum calcium levels be inaccurate? (3)

Answer 8

• Low serum albumin causes a low total serum calcium
• But this is not a low ionised calcium
• Need to do corrected calcium equation

Question 8

Treatment of hypocalcaemia (2)

Answer 8

• Oral calcium replacement or IV calcium gluconate
• Treat the cause

Question 9

response to hypocalcaemia (6)

Answer 9

inc PTH secretion
inc bone reabsorption
dec in urinary excretion
inc calcium reabsorption
inc in 1,25 vitamin D3 production
increase in calcium and phosphate reabsorption in intestine

Question 10

hypocalcaemia tests (5)

Answer 10

ECG - long QT INTERVAL
chvosteks sign
trousseaus sign
serum total Ca below 8.5
ionized blood below 4.4

Question 11

aetiology hypoparathyroidism

Answer 11

• syndromes - eg Di george
• Genetic
• Surgical
• Radiation
• Autoimmune - eg polyglandular type 1
• Infiltration - wilsons disease
• Magnesium deficiency