Endo - Thyroid

Question 1

What are the TSH levels in hyper and hypothyroidism?

Answer 1

Hyper - TSH is SUPPRESSED, by the high thyroid hormones, so low TSH level

Hypo - TSH is HIGH, as trying to stimulate more thyroid hormone release

Question 2

What is the exception to TSH being low in hyperthyroidism?

Answer 2

Pituitary adenoma - secretes TSH, so levels will be high instead of low

Question 3

What is the exception to TSH being high in hypothyroidism?

Answer 3

Pituitary or hypothalamic cause of the hypothyroid (secondary hypothyroidism), in which TSH level will be low

Question 4

What are the T3 and T4 levels in hyper and hypothyroidism?

Answer 4

Hyper - Raised T3 and T4

Primary Hypo - Low T3 and T4

Secondary Hypo - Low T3 and T4

Question 5

What are the antibodies that are against the thyroid gland itself, and what are they present in?

Answer 5

Antithyroid Perioxidase (anti-TPO) antibodies

Present in Grave’s Disease and Hashimoto’s Thyroiditis

Question 6

What are the antibodies called that are against Thyroglobulin, and what is Thyroglobulin?

Answer 6

Antithyroglobulin antibodies

It is a protein produced and extensively present in thyroid gland

Present in Grave’s, Hashimoto’s, and thyroid cancer

Question 7

What are TSH Receptor Antibodies, and what do they classically cause?

Answer 7

Autoantibodies that mimic TSH, bind to TSH receptor, and stimulate thyroid hormone release

Cause of Grave’s Disease

Question 8

What are radioisotope scans?

Answer 8

Used to investigate Hyperthyroidism and thyroid cancers

Question 9

What does radioisotope scans entail?

Answer 9

1. Radioactive iodine given orally or IV
2. Travels to thyroid where it is taken up by cells
3. Iodine normally used by thyroid cells to PRODUCE THYROID HORMONES
4. More active the thyroid cells, faster radioactive iodine is taken up
5. Gamma camera used to detect gamma rays emitted from radioactive iodine
6. More gamma rays emitted, more radioactive iodine taken up

Question 10

What pattern of radioactive iodine uptake would you see in which thyroid disease?

Answer 10

1. Diffuse high uptake - Graves Disease
2. Focal high uptake - Toxic multinodular goitre and adenomas
3. ‘Cold’ areas (abnormally low uptake) - can indicate thyroid cancer