Biochemistry- hypercalcaemia

Question 1

Clinical features of hypercalcaemia?

Answer 1

Neurological and psychiatric features such as lethargy, confusion, irritability and depression

GI problems- such as anorexia, abdominal pain, nausea and vomiting, constipation

Renal features such as thirst, polyuria, renal calculi

Cardiac arrhythmias.

Question 2

What are the two commonest causes of hypercalcaemia?

Answer 2

Primary hyperparathyroidism

Malignancy

Question 3

Helpful treatment/investigation algorythm for hypercalcaemia.

Question 4

What commonly causes hypercalcaemia?

Answer 4

Usually due to a single parathyroid adenoma- which secretes PTH independently of negative feedback.

Question 5

What protein do some tumours secrete leading to hypercalcaemia? What hormone do its properties mimic?

Answer 5

Parathyroid hormone related protein (PTH-like)

Mimics PTH.

Question 6

Name some rarer causes of hypercalcaemia?

Answer 6

Inappropriate dosage of vit D or metabolites.

Granulomatous diseases e.g. sarcoidosis (they synthesis 1,25 hydroxycolicalciferol)

Thyrotoxicosis (can lead to increased bone turnover)

Thiazide therapy (hypercalcaemia is usually mild)

Immobilisation

Renal disease

Question 7

How do you treat hypercalcaemia?

Answer 7

Treatment is urgent if the adjusted serum calcium >3.5mmol.

IV saline is introduced to restore GFR.

Bisphosphonates (inhibit bone reabsorption)

Cause of hypercalcaemia treated (e.g. surgical removal of parathryoid adenoma).

Question 8

What occurs in familial hypercalciuric hypercalcaemia?

Answer 8

High plasma calcium is recognised as being normal. The patient will have normal detectable levels of PTH, despite hypercalcaemia.

Question 9

Does someone with FHH have symptoms?

Answer 9

Usually no symptoms of hypercalcaemia, however they may be labelled as having primary hyperparathyroidism.

Question 10

Does FHH require treatment?

Answer 10

Patients require no treatment.