Principles of endo diseases and it's assessment

Question 1

Two types of assays

Answer 1

Two types of assays:

1. Total hormone assays
2. Free hormone assays

Total hormone assays:
• Dependent on binding protein levels
• Not always reflective of the free hormone levels
• Cheap

Free hormone assays:
• Representative of the active hormone fraction
• Not binding protein dependant
• Complex and expensive
- Have a separation step (can mean its unreliable)
• Can have poor reproducibility

Question 2

What is Technesium?

Answer 2

Technesium is taken up into the gland the same way as iodine.
It is used in technesium scanning to check how biologically active the gland is.

Question 3

How is Thyroiditis caused?

Answer 3

Gland has stored thyroid hormone – so if it were to be broken down (e.g. by a disease), the thyroid hormone can be leaked into the circulation – so symptoms of overproduction, even though the gland is not biologically active.
Since thyroiditis is an inflammatory process – it will have an inflammatory response – ESR (erythrocyte sedimentation rate) and CRP (C-reactive protein) will rise

Question 4

What is sick euthyroid?

Answer 4

• normal T3 and T4.
• low TSH
  • Sick euthyroid – shows the stress response – inhibits the production of TSH – but since the half life of thyroxine is 7-10days, the hormones stay normal.

Question 5

What is T3 toxicosis?

Answer 5

• high T3
• normal T4
• low TSH
  • T3 toxicosis – a condition where you mainly produce T3. – even though the level of T4 is in the normal range, the brain is still able to detect that there’s too much T3.

Question 6

ACTH levels in adrenal tumour

Answer 6

Adrenal tumour – inhibits production of ACTH – so low levels

Question 7

Octreotide scan

Answer 7

An octreotide scan is a non-invasive test used to evaluate the body for the presence of neuroendocrine tumor cells.

Question 8

Difference between the long and the short synacthen tests.

Answer 8

Difference between the 2 tests = the long test includes a much larger dose of ACTH. – we test the cortisol level on the second day (as the gland doesn’t respond on the first day).
- If the gland is too small, there will be regrowth of the gland within the 24 hours. – then cortisol returns to normal