W16 - Clinical chemistry CPC

Question 1

Which of the following commonly presents with depression?

A) hyperkalaemia

B) hypokalaemia

C) hypercalcaemia

D) hypocalcaemia

E) uraemia

Answer 1

C) Hypercalcaemia

potassium affects heart first = hyperK+ gives you ASYSTOLE and hypoK+ gives you VF

calcium affects neurones first = tetany-like symptoms, depression

Question 2

What does this urine dipstick show?

Answer 2

Haematuria (large)

Question 4

What does this XRAY show?

Answer 4

B. Renal stones

Question 5

For a large haematuria => what could be the cause:

A) DKA

B) Glomerulonephritis

C) Acute rheumatic fever

D) Subacute bacterial endocarditis

E) Renal stones

Answer 5

E - most likely => for a LARGE haematuria, it’s likely that a rneal stone has caused a tear and damaged the kidneys

B - the other plausiblecause => usually has less blood

Question 7

In a patient who has depression, previous fracture, and renal stones, what 2 things should you check?

Answer 7

1. Calcium
2. Plasma PTH

Question 8

Patient with depression, wrist fracture, renal stone and raised serum calcium 2.82. Give 3 differential diagnoses

Answer 8

1. Primary hyperparathyroidism
2. Cancer
3. Sarcoidosis

* cancer most common cause in hospital patients

* primary hyperparathyroidism most common cause in community

Question 9

What single investigation can distinguish the cause (cancer, primary hyperparathyroidism, sarcoidosis) of raised calcium?

Answer 9

PTH

Question 10

Calcium high, PTH normal

What is the likely cause?

Answer 10

Primary hyperparathyroidism

LEARNING POINT: if the calcium is high and the PTH is 3.0 (normal) = this is INAPPROPRIATE. if your calcium goes up above 2.6, your PTH will fall to ZERO!! if the calcium is high and the PTH Is not suppressed = this is inappropriate and so it must be primary hyperparathyroidism

Question 11

Rate limiting step in Vitamin D activation?

Answer 11

1 alpha hydroxylation in kidneys

Question 12

What are some symptoms (3) of hypercalcaemia?

Answer 12

1. Asymptomatic (may have subclinical depression)
2. Moans/bones/groans/stones
3. Polydypsia/polyuria (nephrogenic DI) => similar to glucose, cuses osmotic diuresis

Question 13

Band keratopathy - what is this a sign of?

Answer 13

bands of calcium in eyes = hypercalcaemia

Question 14

What is the commonest type of renal stone?

Answer 14

calcium oxalate (40-60%)

Question 15

This is a bone histo. What do you see?

Answer 15

Large pink cells are activated osteoclasts in the bone => due to high PTH from hyperparathyroidism => Brown Tumour

Question 16

What are 6 findings of longterm (chronic) hypercalcaemia?

Answer 16

1. nephrocalcinosis
2. renal stone
3. salt and pepper skull
4. vertebrae osteoporosis
5. band keratopathy
6. pancreatitis
7. calcium deposits in blood vessels/hypertension/HF

Question 17

Primary hyperparathyroidism:

Acute management of hypercalcaemia

Long-term management of hypercalcaemia

Answer 17

Acute => IV fluids (normal saline) LOTS

Long-term => keep well hydrated, avoid thiazides, surgery (parathyroidectomy i.e.)

Question 19

What will the hand X-ray of someone with primary hyperparathyroidism show?

Answer 19

Radial aspect cystic changes

Question 20

What will the histology of the bone show in someone with long-standing primary hyperparathyroidism?

Answer 20

Brown tumours