Thyroid - Thyrotoxicosis

Question 1

What effect does thyrotoxicosis have on weight and appetite?

Answer 1

Increased appetite and weight loss

Question 2

What arrhythmias may be seen in patients with thyrotoxicosis?

Answer 2

Atrial fibrillation, SVT

Question 3

Are individuals with thyrotoxicosis intolerant of the heat or the cold?

Answer 3

Heat

Question 4

What effect does thyrotoxicosis have on the menstrual cycle?

Answer 4

Lighter and less frequent periods +/- infertility

Question 5

How does a thyroid storm typically present?

Answer 5

Respiratory and cardiovascular collapse, hyperthermia and brisk reflexes

Question 6

When does a thyroid storm typically occur?

Answer 6

In those with pre-existing thyrotoxicosis with acute illness or after thyroid surgery/radioiodine treatment

Question 7

A thyroid storm should be treated with an ABCDE approach. What medication is given to counteract the peripheral effects of thyroid hormones?

Answer 7

Beta blockers (propranolol)

Question 8

Which autoantibodies are most commonly associated with Grave’s disease?

Answer 8

Anti TSH receptor antibodies (TRAb)

Question 9

What are some potential triggers for Grave’s disease?

Answer 9

Stress, infection, childbirth

Question 10

Who does Grave’s disease typically affect?

Answer 10

Women aged 20-50

Question 11

What are some signs of thyrotoxicosis that are specific to Grave’s disease?

Answer 11

Pretibial myxoedema, Grave’s eye disease, thyroid bruit, thyroid acropatchy

Question 12

What is the biggest risk factor for Grave’s eye disease?

Answer 12

Smoking

Question 13

What is the relationship between Grave’s eye disease and gender?

Answer 13

It is less likely to occur in males, but when it does it is usually worse

Question 14

Low TSH, high free T3/4 and high TRAb levels suggests what diagnosis? Are any further investigations necessary?

Answer 14

Grave’s disease - no further investigations are necessary

Question 15

Hypercalcaemia and a high ALP in those with Grave’s disease suggests that what complication has occurred?

Answer 15

Osteoporosis

Question 16

Who is toxic multinodular goitre most commonly seen in?

Answer 16

The elderly, and those from iodine deficient areas

Question 17

Low TSH, high free T3/4, antibody and inflammatory markers negative suggests what diagnosis? Are any further investigations necessary?

Answer 17

Toxic multinodular goitre - a radioisotope scan, ultrasound +/- FNA will also be required to confirm the diagnosis

Question 18

Will a radioisotope scan of toxic multinodular goitre be hot, warm or cold?

Answer 18

Hot

Question 19

If a person has thyrotoxicosis and undergoes a radioisotope scan which shows a hot solitary nodule, but the rest of the gland is suppressed, what diagnosis does this suggest?

Answer 19

Toxic solitary adenoma

Question 20

What are some inflammatory causes of thyrotoxicosis?

Answer 20

DeQuervain’s thyroiditis, postpartum thyroiditis, drug induced thyroiditis

Question 21

What drug is most likely to cause thyrotoxicosis?

Answer 21

Amiodarone

Question 22

If someone presents with thyrotoxicosis, and has a raised T4, low T3 and low thyroglobulin, what diagnosis does this suggest?

Answer 22

Over-treatment with levothyroxine (accidental or factitious)

Question 23

What are some potential causes of ectopic endogenous thyroid hormone exposure leading to thyrotoxicosis?

Answer 23

Metastatic follicular thyroid carcinoma, ovarian teratoma, carcinoid tumours

Question 24

What is the first line treatment for Grave’s disease?

Answer 24

Medical management

Question 25

What is the mechanism of action of both drugs that can be used to treat Grave's disease?

Answer 25

Inhibition of TPO (thereby blocking thyroid hormone synthesis)

Question 26

What is the first line drug used to treat Grave's disease?

Answer 26

Carbimazole

Question 27

What is the second line drug used to treat Grave's disease?

Answer 27

Propothiouracil (PTU)

Question 28

When should PTU be used over carbimazole in the treatment of Grave's disease?

Answer 28

In early pregnancy

Question 29

What is the major side effect of carbimazole to be aware of and patients should be warned of?

Answer 29

Agranulocytosis

Question 30

Drugs used to treat Grave's disease are most likely to cause side effects related to which body organ?

Answer 30

Liver (jaundice, raised enzymes, hepatic failure)

Question 31

The risk of agranulocytosis with carbimazole treatment is highest when?

Answer 31

In the first 6 weeks of treatment

Question 32

If patients taking carbimazole experience any symptoms/signs of infection, what blood test must be taken urgently?

Answer 32

FBC

Question 33

What medication can be useful for symptomatic relief from thyrotoxicosis?

Answer 33

Beta blockers (propranolol)

Question 34

Explain what is meant by the titration method of giving carbimazole to patients with Grave's disease?

Answer 34

Carbimazole is given for 4 weeks and the dose is reduced gradually every 1-2 months according to the TFTs

Question 35

Explain what is meant by the block and replace method of giving carbimazole to patients with Grave's disease? What is the main advantage of this method?

Answer 35

Carbimazole and levothyroxine are given simultaneously - this reduces the risk of iatrogenic hypothyroidism

Question 36

How long should patients with Grave's disease be maintained on medications? What is the outcome after this?

Answer 36

12-18 months - after this 50% will be treated and 50% will relapse, requiring radioiodine or surgical treatment

Question 37

What is the first line treatment for toxic multinodular goitre?

Answer 37

Radioiodine

Question 38

What is the second line treatment for Grave's disease if medical management fails?

Answer 38

Radioiodine

Question 39

What isotope is most commonly used to treat thyrotoxicosis?

Answer 39

131 iodine

Question 40

What are the outcomes of a single oral dose of 131 iodine when treating thyrotoxic patients?

Answer 40

50% hypothyroid, 20% hyperthyroid, 30% euthyroid

Question 41

Does radioiodine treatment for thyrotoxicosis increase the risk of developing thyroid cancer?

Answer 41

No

Question 42

What are the contraindications to radioiodine treatment for thyrotoxicosis?

Answer 42

Pregnancy, breastfeeding, children, Grave's eye disease (relative)

Question 43

It is advised to avoid pregnancy for how long after receiving radioiodine treatment for thyrotoxicosis?

Answer 43

4 months

Question 44

What is the first line management option for toxic multinodular goitre causing compression symptoms e.g. dysphagia, dyspnoea?

Answer 44

Surgical management

Question 45

What is the next best management option for toxic multinodular goitre or Grave's disease when radioiodine treatment is contraindicated?

Answer 45

Surgical management

Question 46

What is the surgical procedure of choice for treating thyrotoxicosis?

Answer 46

Subtotal thyroidectomy

Question 47

What must patient's thyroid function be before undergoing surgery for thyrotoxicosis and why?

Answer 47

Normal - to reduce the risk of complications, especially a thyroid storm

Question 48

What are some risks of subtotal thyroidectomy for thyrotoxicosis?

Answer 48

Hypothyroidism, hypoparathyroidism, recurrent laryngeal nerve palsy

Question 49

If an individual has thyrotoxicosis, and they have patchy uptake on radioisotope scanning, what is the most likely diagnosis?

Answer 49

Toxic multinodular goitre

Question 50

If an individual has thyrotoxicosis, and they have uniform uptake but diffuse enlargement of both lobes of the thyroid, what is the most likely diagnosis?

Answer 50

Grave's disease

Question 51

How should a thyroid storm be treated?

Answer 51

Beta blockers, PTU, hydrocortisone

Question 52

What effect can thyrotoxicosis have on the heart, particularly of elderly individuals?

Answer 52

High output cardiac failure

Question 53

What happens to the level of thyroxine binding globulin and T4 output in pregnancy?

Answer 53

Increased

Question 54

What happens to levels of TSH in the first trimester of pregnancy and why?

Answer 54

They decrease, because it is suppressed by HCG

Question 55

What happens to the severity of pre-existing thyrotoxicosis in and around pregnancy?

Answer 55

Generally improves in pregnancy, but may experience transient exacerbations in the first trimester and post-partum

Question 56

Why is PTU used over carbimazole for thyrotoxicosis which is diagnosed during pregnancy?

Answer 56

Less crosses the placenta and less is concentrated in breast milk

Question 57

Can thyroid surgery be performed in pregnancy?

Answer 57

Only in the second trimester

Question 58

If a pregnant mother has been on anti-thyroid medications, signs of neonatal thyrotoxicosis may not occur until when?

Answer 58

7-10 days post-partum

Question 59

What is the outcome of neonatal thyrotoxicosis?

Answer 59

Most cases resolve spontaneously by 2-3 months

Question 60

What are some long-term effects of neonatal thyrotoxicosis that may occur?

Answer 60

Motor difficulties and hyperactivity