Thyoid disorders

Question 1

What is the isthmus of the thyroid gland

Answer 1

the bit that joins up the lobes

Question 2

What percentage of the population is the pyramidal lobe present in

Answer 2

50%

Question 3

What is the hypothalamic-pituitary-thyroid axis

Answer 3

Hypothalamus -> TRH -> Pituitary -> TSH -> Thyroid Gland -> T3/4 that act on hypothalamus and pituitary

Question 4

What do para-follicular cells (C cells) produce?

Answer 4

calcitonin (calcium metabolism)

Question 5

Where is thyroglobulin made and stored?

Answer 5

made in follicular cells, stored in colloid

Question 6

What does thyroglobulin

Answer 6

tyrosine, iodinated tyrosine, pre-formed thyroid hormones

Question 7

what is monoiodotyrosine

Answer 7

tyrosine +iodine

Question 8

what is diiodotyrosine

Answer 8

monoiodotyrosine +iodine

Question 9

What is T3/triiodothyronine

Answer 9

mono + di - iodotyrosine

Question 10

What is T4/tetriodothyronine

Answer 10

2 x diiodotyrosine

Question 11

What is enlargement of the thyroid called

Answer 11

goitre

Question 12

what is hyperthyroidism

Answer 12

too much thyroid hormone - metabolism speed up

Question 13

what is hypothyroidism

Answer 13

too little thyroid hormone - metabolism slows down

Question 14

common signs of hyperthyroidism

Answer 14

nervousness, irritability, weight loss, heat intolerance, goiter, warm moist skin, sweating

Question 15

less common signs of hyperthyroidism

Answer 15

dyspnoea, increased bowel frequency, atrial fibrillation

Question 16

commonest cause of hyperthyroidism

Answer 16

graves disease - 80%

toxic multinodular goitre - 15%

Question 17

uncommon causes of hyperthyroidism

Answer 17

toxic adenoma/hot nodule - 2%

thyroiditis - 1%

Question 18

rare causes of hyperthyroidism

Answer 18

TSH secreting tumour, trophoblastic tumours (high [HCGH] interacts with TSHR)

Question 19

eye symptoms of graves

Answer 19

exopthalmos (proptosis), periorbital oedema, chemosmosis, lid retraction/lag,

Question 20

clinical considerations in patients older than 70 years

Answer 20

1. classical S/S may be lacking
2. goitre may be absent
3. anorexia with wasting
4. af or congestive heart failure may be predominant manifestations

Question 21

hallmark of hyperthyroidism

Answer 21

suppressed TSH

Question 22

If a patient has overt opthalmopathy:

Answer 22

No additional testing required

Question 23

Imaging investigations

Answer 23

Ultrasound or nuclear medicine

Question 24

Autoantibody assays

Answer 24

TPO, TSH receptor

Question 25

How to establish cause of thyrotixicosis in patient without opthalmopathy

Answer 25

Iodine131 uptake - increased uptake in hyperthyroidism; lack of uptake in thyroiditis and iodine ingestion - in MND it defines the functional characteristics of the gland

Question 26

(3) Treatment of hyperthyroidism

Answer 26

Antithyroid drugs (ATD), radioiodine (Iodine131), Subtotal thyroidectomy

Question 27

Factors affecting treatment of hyperthyroidism

Answer 27

Age of patient, size of goitre, presence of co-existing condition

Question 28

Drug for mild thyroid disease, small goiter

Answer 28

thiocarbamides e.g., PTU, carbimazole,

Question 29

Treatments for hyperthyroid storm

Answer 29

beta blockers, glucocorticoids, iodine

Question 30

Is hyperthyroidism treatment safe for pregnant women?

Answer 30

Drugs safe in pregnancy, although some might switch PTU for CMZ, no contraindication to breast feeding