Thyroid Disease

Question 1

What activates the thyroid to release hormones?

Answer 1

TRH is released from the hypothalamus, leading to TSH being secreted by the anterior pituitary. The TSH then travels to the thyroid, bringing about the release of thyroid hormones.

Question 2

What are potential causes of thyroiditis?

Answer 2

Autoimmune
Infection
Subacute
Lymphocytic
Palpation

Question 3

What is the most prevalent cause of hyperthyroidism?

Answer 3

Grave’s disease

Question 4

What causes Grave’s disease?

Answer 4

The presence of autoantibodies that act on TSH receptors, stimulating function.

Question 5

What are the 3 main features in Grave’s disease?

Answer 5

Hyperthyroidism, with enlarged thyroid gland
Eye changes (exophthalmos)
Pretibial myxoedema

Question 6

What is the most common cause of hypothyroidism?

Answer 6

Hashimoto’s thyroiditis

Question 7

Besides Hashimoto’s thyroiditis, what other causes exist for hypothyroidism?

Answer 7

Iodine deficiency
Drugs
Congenital abnormalities

Question 8

What is a goitre?

Answer 8

Any enlargement of the thyroid gland.

Often, this is a result of a lack of dietary iodine.

Question 9

What is the most common form of thyroid cancer?

Answer 9

Papillary thyroid carcinoma

Question 10

What are common benign causes of thyroid nodules?

Answer 10

Cysts
Colloid nodules
Benign follicular adenomas
Hyperplastic nodules

Question 11

What type of thyroid cancer is associated with MEN type 2b syndrome?

Answer 11

Medullary thyroid carcinomas

Question 12

Following an examination and history, how should a thyroid nodule be investigated?

Answer 12

Measure TSH levels
Ultrasound

Question 13

What is the biggest risk factor for thyroid lymphoma?

Answer 13

Hashimoto’s thyroiditis

Question 14

How is thyroid lymphoma treated?

Answer 14

R-CHOP chemotherapy
Radiotherapy
Steroids

Question 15

How can bothersome toxic multinodular goitres be managed?

Answer 15

Radioactive iodine

If structural issues, or patient finds it unsightly, then surgery can be used.

Question 16

Where do secondary thyroid diseases occur?

Answer 16

Pituitary or hypothalamus.

Question 17

How do thyroid hormones present in primary hypothyroidism?

Answer 17

Low free T3
Low free T4
Raised TSH

Question 18

How do thyroid hormones present in primary hyperthyroidism?

Answer 18

High free T3
High free T4
Low TSH

Question 19

How do thyroid hormones present in secondary hypothyroidism?

Answer 19

Low T3
Low T4
Low TSH (no response to low T3/T4)

Question 20

How do thyroid hormones present in secondary hyperthyroidism?

Answer 20

High T3
High T4
High TSH (no response to elevated T3/T4 levels)

Question 21

What is the difference between myxoedema and pretibial myxoedema?

Answer 21

Myxoedema is a severe form of hypothyroidism.

Pretibial myxoedema is a rare complication of hyperthyroidism.

Question 22

Name a drug that can cause hypothyroidism?

Answer 22

Amiodarone

Question 23

Which antibodies are linked to Hashimoto’s thryoiditis?

Answer 23

anti-TPO

Question 24

How is primary hypothyroidism diagnosed?

Answer 24

TFT (low T3/T4, and raised TSH)
Look for presence of anti-TPO (seen in 95% of people)

Question 25

Should dose of levothyroxine differ depending on age?

Answer 25

Yes, younger patients get 50-100ug whereas elderly patients get 25-50ug. Often the initial dose is changed - these are just beginning values for treatment.

Question 26

Why do pregnant patients need a higher dose of levothyroxine?

Answer 26

As there are greater TBG levels in pregnancy, meaning less free T4 available.

Question 27

What is the main treatment of hypothyroidism?

Answer 27

Levothyroxine

Question 28

What drugs can impair the efficacy of levothyroxine?

Answer 28

PPIs Iron tablets Calcium tablets

Question 29

What is myxoedema coma?

Answer 29

A severe form of hypothyroidism in which significant bradycardia and type 2 respiratory failure develop. There may also be adrenal failure. It is associated with a high mortality rate (60%).

Question 30

What is thyrotoxicosis?

Answer 30

The clinical state of hypothyroidism - the latter refers only to the condition which produces thyrotoxicosis.

Question 31

If TSH antibodies are found, do you need to carry out thyroid imaging to diagnose Grave's disease?

Answer 31

No, antibody presence is sufficient.

Question 32

What is thyroid storm?

Answer 32

A severe form of hyperthyroidism, in which there is significant respiratory and cardiovascular collapse. Will have hypothermia, and exaggerated reflexes.

Question 33

In which types of patients does thyroid storm present?

Answer 33

Acutely unwell hyperthyroid patients Recent thyroid surgery

Question 34

What is the first-line treatment of hyperthyroidism?

Answer 34

Carbimazole

Question 35

In which trimester of pregnancy should propylthiouracil be used over carbimazole?

Answer 35

1st trimester of pregnancy.

Question 36

What antithyroid medication may cause agranulocytosis?

Answer 36

Carbimazole

Question 37

What does normal thyroid levels, but abnormal TSH levels indicate?

Answer 37

Subclinical hypothyroidism/hypethyroidism

Question 38

What is sick euthyroid syndrome?

Answer 38

When an intercurrent illness affects the thyroid, commonly seen in hospitalised patients. As a result, avoid thyroid testing in hospital unless it appears as a thyroid disease specifically.

Question 39

What are the 5 types of thyroid cancer?

Answer 39

Papillary (most common) Follicular Medullary Anaplastic Other

Question 40

What forms of thyroid cancer belong to the differentiated sub-set?

Answer 40

Papillary Follicular

Question 41

What are differentiated thyroid cancers dependent on to grow?

Answer 41

TSH These cancers take up iodine and release thyroglobulin (like normal thyroid tissue).

Question 42

How do papillary and follicular thyroid cancers differ?

Answer 42

Papillary thyroid cancers favour lymphatic spread, whereas follicular spread more via haematogenous routes.

Question 43

How are differentiated thyroid cancers treated?

Answer 43

Surgery This may be a thyroid lobectomy with isthmusectomy, sub-total thyroidectomy, or a total thyroidectomy.

Question 44

What form of thyroid cancer is associated with Hashimoto's thyroiditis?

Answer 44

Papillary carcinoma

Question 45

Alongside surgery, what is used in the management of thyroid cancer?

Answer 45

Whole body iodine scanning Only after sub-total/total thyroidectomy - as this shows whether any thyroid tissue remains within the body. Thus, will identify remnants, normal thyroid and metastasis.

Question 46

If whole body iodine scanning detects metastasis, what is the remaining treatment option?

Answer 46

Thyroid remnant ablation This acts to make cells hungry through administration of high TSH, before giving radioactive iodine - which kills them off.

Question 47

What can be used as a marker in TRA?

Answer 47

Thyroglobulin If treatment was successful, none will present in blood (as only produced within thyroid tissue).

Question 48

Can recurrent differentiated thyroid cancers be treated?

Answer 48

Yes, if the cells continue to take up iodine, then TRA can be used. If resistant to iodine, try tyrosine kinase inhibitors.

Question 49

What is the first-line investigation for a new thyroid lump?

Answer 49

Thyroid function test

Question 50

Following TFTs, how is a new thyroid lump investigated?

Answer 50

USS, if inconclusive perform a FNA.

Question 51

What is pretibial myxoedema?

Answer 51

A rash that occurs in hyperthyroidism.

Question 52

What treatment is contraindicated in thyroid eye disease?

Answer 52

RAI (radioactive iodine)