Clinical Chemistry CPC

Question 1

What abnormality of calcium is associated with depression?

Answer 1

Hypercalcaemia

Question 2

What is a Smith’s fracture?

Answer 2

Radius fracturing forwards (towards the palm) - falling on a flexed wrist

Question 3

What is a Colles fracture?

Answer 3

Falling on an outstretched palm - radius fractures backwards, away from the palm

Question 4

Differentials for hypercalcaemia

Answer 4

Cancer
Primary hyperparathyroidism
Sarcoidosis

Question 5

What is the PTH in hypercalcaemia of malignancy?

Answer 5

0

Zero

Question 6

Which organ physiologically produces PTHrP?

Answer 6

Placenta - increases calcium in the mother so that the baby can take it and create a skeleton

Question 7

What are the two methods by which cancer can cause hypercalcaemia?

Answer 7

Metastasis/invasion of bone

PTHrP

Question 8

What is the main cause of primary hyperparathyroidism?

Answer 8

Parathyroid adenoma

Question 9

Which condition is associated with multiple parathyroid adenomas?

Answer 9

MEN1

Question 10

Clinical features of hypercalcaemia

Answer 10

Moans, bones, groans, stones
Can be asymptomatic
Polydipsia/polyuria

Question 11

What is a sign of chronic hypercalcaemia?

Answer 11

Band keratopathy - band of calcium across the eye

Question 12

Are calcium stones opaque or lucent?

Answer 12

Opaque - not transparent

Question 13

Complications of hypercalcaemia

Answer 13

Renal stones
Pancreatitis
Peptic ulcer disease
Skeletal changes - osteitis fibrosa cystica

Question 14

What type of stones are associated with Proteus mirabilis infection?

Answer 14

Struvite

Question 15

How can hypercalicuria be medically treated?

Answer 15

Thiazide diuretics

Treat the hypercalcaemia

Question 16

Management of emergency hypercalcaemia

Answer 16

Only when calcium > 3.0

IV access
Catheter
Rehydrate - FLUIDS - will need up to 6L in the first 24 hours
Give first L quickly + furosemide in elderly people

IF in liver failure - use dextrose

Question 17

Management of non-emergency hypercalcaemia

Answer 17

Keep hydrated
Avoid thiazide diuretics
Surgery - parathyroidectomy

Question 18

What is a long-standing feature of undiagnosed hyperparathyroidism?

Answer 18

Brown tumours - multinucleate giant cells in the bone, these are activated osteoclasts

Question 19

How does sarcoidosis cause hypercalcaemia?

Answer 19

Macrophages in the lungs express 1-alpha hydroxylase which will activate vitamin D

More likely to occur in the summer due to more sunlight