Hypocalcaemia

Question 1

What are causes of hypocalcaemia?

Answer 1

Low PTH: parathyroidectomy, autoimmune hypoparathyroidism, hypomagnasaemia

High PTH: vit D deficiency, CKD, hypomagnasaemia

Bisphosphonates, pancreatitis

Question 2

What are Sx of hypocalcaemia?

Answer 2

Tetany
peri-oral numbness
muscle cramps
tingling in hands and feet
dysrthymia
carpopedal spaspm, seizures

if chronic: depression, cataracts

Question 3

What Ix in hypocalcaemia?

Answer 3

Ca, PTH, Mg, vit D

ECG: prolonged QTc

Question 4

What DDx in hypocalcaemia

Answer 4

Diff causes
vitamin D deficiency (osteomalacia)
chronic kidney disease
hypoparathyroidism (e.g. post thyroid/parathyroid surgery)
pseudohypoparathyroidism (target cells insensitive to PTH)
rhabdomyolysis (initial stages)
magnesium deficiency (due to end organ PTH resistance)
massive blood transfusion
acute pancreatitis

Question 5

What is Rx of hypocalcaemia?

Answer 5

IV Ca if tetany or cardiac issues calcium gluconate, 10ml of 10% solution over 10 minutes

Mg infusion if low

Vit D, oral Ca salts

treat cause

Question 6

What is Trosseaus sign

Answer 6

carpal spasm if the brachial artery occluded by inflating the blood pressure cuff and maintaining pressure above systolic
wrist flexion and fingers are drawn together
seen in around 95% of patients with hypocalcaemia and around 1% of normocalcaemic people

Question 7

What is Chvostek’s sign

Answer 7

tapping over parotid causes facial muscles to twitch

seen in around 70% of patients with hypocalcaemia and around 10% of normocalcaemic people