Core Clinical Biochemistry

Question 1

What are the components of the triad that patients with primary adrenal cortical insufficiency present with?

What might this be caused by?

Answer 1

Primary adrenal cortical insufficiency may be caused by adrenal dysgenesis, adrenal destruction or autoimmune adrenalitis

They show a triad of:

1. Postural hypotension
2. Hyponatraemia
3. Hyperpigmentation

Question 2

What happens when bone density decreases?

Answer 2

There is a decrease in the rate of bone formation compared to the rate of bone resorption

Question 3

How does parathyroid hormone affect serum calcium levels?

Answer 3

The net effect of parathyroid hormone is to increase serum calcium levels

Question 4

What type of tumour are the vast majority of primary pituitary tumours?

Answer 4

Adenoma

These are benign

Question 5

What is there an 80 fold increased risk of in a condition that causes diffuse enlargement of the thyroid gland and thyroid autoantibodies?

Answer 5

Lymphoma

Question 6

What does a growth hormone secreting pituitary tumour cause in children and adults?

Answer 6

It causes gigantism in children and acromegaly in adults

Question 7

What can the most common tumour of the islets of Langerhans cause?

Answer 7

Hypoglycaemia

This leads to sweating, anxiety, palpitations and other signs and symptoms

Question 8

What is HbA1c?

Answer 8

Glycated haemoglobin

Question 9

In multinodular goitre, what can a dominant nodule be clinically mistaken for?

Answer 9

Carcinoma

This leads to unnecessary surgical resection

Question 10

What happens after autoimmune destruction of the beta cells in the islets of Langerhans?

Answer 10

There is a rapid onset of ketoacidosis

Question 11

What does an adult adrenal medullary tumour that causes paroxysmal features release?

Answer 11

Catecholamines

The paroxysmal features include hypertension, panic attacks and headaches

Question 12

How can calcium levels be different in a patient with low albumin?

What can be used to get a more accurate picture?

Answer 12

In patients with low albumin, the total calcium can be low even though the calcium level is normal

It is more accurate to measure ionised calcium using a blood gas analyser

Question 13

What is the commonest type of thyroid carcinoma?

Answer 13

Papillary carcinoma

This is more common in females And can be secondary to radiation

It can occur at quite young ages