Chempath 9: Thyroid

Question 1

Which auto-antibodies are seen in Hashimoto’s thyroiditis ?

Answer 1

anti-TPO

also anti-TG

Question 2

Which auto-antibodies are seen in Grave’s disease?

Answer 2

anti-TSH receptor (activates Thyroid production)

Question 3

what is the most common type of thyroid cancer?

Answer 3

Pappilary thyroid cancer

Question 4

In which cancer are Psammoma bodies seen on histology ?

Answer 4

Papillary thyroid

also ovarian serous cyst adenoma

Question 5

which thyroid cancer is associated with MEN2 ?

Answer 5

Medullary thyroid cancer

Question 6

Which thyroid cancer releases calcitonin ?

Answer 6

Medullary thyroid cancer

Question 7

List the 3 cancers seen in MEN1

Answer 7

Pituitary
Parathyroid
Pancreatic (Insulinoma)

3 Ps

Question 8

List the 3 cancers seen in MEN2a

Answer 8

Phaeochromocytoma
Parathyroid
Medullary thyroid

2 Ps 1 M

Question 9

List the 3 cancers seen in MEN2b

Answer 9

Phaeochromocytoma
Medullary thyroid
Mucocutaneous neuromas
1 P 2 Ms

Question 10

What is the mode of inheritance for MEN ?

Answer 10

Autosomal dominant

Question 11

List 2 causes of hyperthyroidism with high iodine uptake ?

Answer 11

Grave’s disease

Multinodular goitre

Question 12

List 2 causes of hyperthyroidism with low iodine uptake ?

Answer 12

De Quervains thyroiditis

Post partum thyroiditis

Question 13

List causes of hypothyroidism ?

Answer 13

Hashimoto's thyroiditis 
Atrophic hypothyroidism 
Iodine deficiency 
post thyroidectomy/Post radioactive iodine 
Drugs- Lithium, Amiodarone

Question 14

Which drug can be used to treat hyperthyroidism without inducing permanent hypothyroidism?

Answer 14

carbimazole

Question 15

how is thyroxine made

Answer 15

TSH controls the uptake of iodide to the thyroid (blocked by perchlorate)
Iodide goes through the membrane via Na+/l+/ATPase
Iodide converted to iodine by thyroid peroxidase
Iodine taken up by thyroglobulin and converted into thyroxine (T4)
Converted to T3 in the periphery

Question 16

how is most thyroxine transported around the body

Answer 16

bound to thyroxine binding globulin (TBG)

Question 17

list causes of hypothyroidism

Answer 17

Hashimotos thyroiditis 
atrophic thyroid
post-graves disease
drugs (amiodarone, lithium)
thyroid agenesis/dysgenesis

Question 18

why would you do an ECG in someone with hypothyroidism

Answer 18

if they have an underlying cardiovascular disease, their myocardial contractility will increase - risk of ischaemia

Question 19

how is hypothyroidism treated

Answer 19

T4 (levothyroxine)

Question 20

features of subclinical hypothyroidism

Answer 20

T4 is normal and TSH high

associated with hypercholesterolaemia

Question 21

describe thyroid function in pregnancy

Answer 21

hCG has a similar structure to TSH
too much hCG - thyroid gland makes too much thyroxine
rise in hCG in first trimester makes free T4 levels increase slightly
TBG levels increase dramatically in pregnancy (under control of oestrogen)

Question 22

features of neonatal hypothyroidism

Answer 22

diagnosed via Guthrie test
48-72 hours
may be very high if you detect maternal TSH

Question 23

features of sick euthyroid

Answer 23

alteratio in pituitary axis in non-thyroidal illness
low T4 and T3
normal/high TSH
in any severe illness

Question 24

causes of hyperthyroidism

Answer 24

graves (40-60%)
toxic multinodiular goitre (30-50%)
single toxic adenoma (5%)

use a technetium scan to see which parts of the thyroid are making excessive thyroid hormone

Question 25

management for hyperthyroidism

Answer 25

beta blocker if pulse >100 
ECG
bone mineral density 
radioactive iodine 
thionamides - carbimazole, propylthiouracil, prevent the conversion of iodine to iodine by thyroid peroxidase

Question 26

what is a rare side effects of thionamides

Answer 26

agranulocytosis

Question 27

features of thyroiditis

Answer 27

can be asymptomatic
some form of pain in the neck
initial inflammation of the thyroid releasing excessive amounts of thyroid hormone
long-term treatment = thyroid replacement therapy

Question 28

list the 2 most common types of thyroid carcinoma

Answer 28

papillary thyroid cancer

follicular thyroid cancer

Question 29

treatment for thyroid carcinoma

Answer 29

total thyroidectomy
radioiodine after surgery to remove any remaining thyroid cells
after this, given high dose thyroxine to lower TSH levels so TSH doesn’t stimulate any remaining cancer cells
TG measured in the serum as a tumour marker

Question 30

features of medullary carcinoma of the thyroid gland

Answer 30

rare
can be sporadic, familial, or part of MEN 2
cancer of the C cells of the thyroid gland (these make calcitonin)
tumour makers:
- calcitonin
- CEA (carcionoembryonic antigen)