Hyperthyroidism

Question 1

What is a Goitre?

Answer 1

Painless enlargement of the thyroid gland

Question 2

What are the key characteristics of a goitre to comment on?

Answer 2

Diffuse vs nodular
Simple vs toxic (secreting)
Benign vs malignant

Question 3

What is the ddx for a diffuse goitre?

Answer 3

Physiological - Puberty, pregnancy
Autoimmune - Grave's, Hashimoto's
Thyroiditis - De Quervain's , Riedel's
Endemic - Iodine deficiency
Drugs - Anti-thyroid drugs, lithium, amiodarone, iodine excess

Question 4

What is the ddx for a nodular goitre?

Answer 4

Multinodular - Toxic multinodular, subacute thyroiditis
Solitary - Follicular adenoma, benign nodule, malignancy, lymphoma met
Infiltration - TB, sarcoid

Question 5

What is the main local complication of a goitre?

Answer 5

Retrosternal extension

Pressure sx on trachea, oesophagus or vv

Question 6

What investigations are appropriate when a pt presents with a goitre?

Answer 6

FBC (anaemia)
ESR
TFTs
Thyroid autoantibodies
CT
USS
FNAC

Question 7

What determines the management of a goitre?

Answer 7

Whether the pt is hyper/hypothyroid

If eu-thyroid do not need to treat

Question 8

What is Thyrotoxicosis?

Answer 8

Clinical disorder resulting from raised circulating levels of thyroid hormone

Question 9

How common is Thyrotoxicosis?

Answer 9

1% of population

5:1 female preponderance

Question 10

What are the common causes of Thyrotoxicosis?

Answer 10

Grave’s disease

Toxic multinodular goitre

Question 11

What are the less common causes of Thyrotoxicosis?

Answer 11

Solitary toxic adenoma (Plummer's)
Thyroiditis
Drug induced (Amiodarone, levothyroxine)
Excess iodine
Hashitoxicosis

Question 12

What are the rare causes of Thyrotoxicosis?

Answer 12

2o causes

• TSH secreting pituitary adenoma
• Resistance to thyroid hormone

Question 13

What is Grave’s disease?

Answer 13

Autoimmune condition where IgG autoantibodies stimulate thyroid follicular cells
Out of control of normal feedback mechanism

Question 14

What is Toxic Multinodular Goitre?

Answer 14

Several hyperactive nodules develop
Outside of TSH control
Common in older women

Question 15

What are the sx of Thyrotoxicosis?

Answer 15

Anxiety/irritability
Heat intolerance/sweating
Increased appetite
Palpitations
Wt loss
Tremor
Loose motions
Fatigue/weakness

Question 16

What are the signs of Thyrotoxicosis?

Answer 16

Lid retraction/lag
Systolic HTN
Tachycardia/AF
Tremor
Hyper-reflexia
Warm peripheries
Proximal weakness

Question 17

What signs of Thyrotoxicosis are unique to Grave’s disease?

Answer 17

Grave’s ophthalmopathy
Goitre/bruit
Acropachy
Pre-tibial myxoedema

Question 18

What is Grave’s ophthalmopathy?

Answer 18

Lagopthalmos (unable to close eyes completely)
Exopthalmos/proptosis (bulging eyes)
Ophthalmoplegia (up & lat)
Periorbital oedema

Question 19

What is acropachy?

Answer 19

Dermopathy associated w/ Graves
Soft tissue swelling of hands
Clubbing of fingers

Question 20

What is pre-tibial myxoedema?

Answer 20

Dermopathy associated w/ Graves

Swelling of lower legs

Question 21

What is Thyroid crisis/storm?

Answer 21

Rare presentation occurring in periods of stress in people w/ untreated hyperthyroidism

Question 22

How does Thyroid crisis/storm present?

Answer 22

Hyperpyrexia
Severe tachycardia
Profuse sweating
Confusion/psychosis
Coma/death

Question 23

How should Thyroid crisis/storm be managed?

Answer 23

Propylthiouracil
Propranolol
Sodium Iodide
High dose steroids

Question 24

What investigations are appropriate in suspected Thyrotoxicosis?

Answer 24

TSH (suppressed)
T3/T4 (elevated)
TRAb (elevated in Grave's)
Technetium uptake scan
CT/MRI of orbit

Question 25

What are the management options for Thyrotoxicosis in primary care?

Answer 25

Non-selective B-blocker (propranolol)- -20-40mg t.d.s. Refer to endocrinologist

Question 26

What are the management options for Thyrotoxicosis in secondary care?

Answer 26

Antithyroid drugs Radioacive Iodine Surgical management

Question 27

What antithyroid drugs are available?

Answer 27

Carbimazole (1st line) | Propylthiouracil (2nd line)

Question 28

What is the main complication of Propylthiouracil?

Answer 28

Risk of severe liver injury (1/10000)

Question 29

How do antithyroid drugs work?

Answer 29

Act as substrates for TPO | Prevent thyroid hormone synthesis

Question 30

What are the main s/e of antithyroid drugs?

Answer 30

``` Skin rashes Severe agranulocytosis (mouth ulceration, sore throat, fever) ```

Question 31

What is the main complication of Carbimazole?

Answer 31

Can cause cholestatic jaundice

Question 32

How are antithyroid drugs introduced?

Answer 32

Intermediate course to induce remission (6-18mo) Titration (starting high, titrating down to euthyroid) Block & replace (maintain high, add thyroxine once T3/T4 controlled)

Question 33

What is the success rate of anithyroid medications?

Answer 33

50%

Question 34

When are antithyroid drugs most commonly used?

Answer 34

Grave's disease mainly

Question 35

When is Radio-active Iodine (RAI) therapy used?

Answer 35

1st line in non-Grave's pathology | Grave's where drug therapy failed

Question 36

How does RAI therapy work?

Answer 36

Taken up by thyroid cells | Induces DNA damage & cell death

Question 37

When is RAI contraindicated?

Answer 37

Pregnancy Active Grave's ophthalmopathy If anti-thyroid drugs not discontinued/discontinued <1wk

Question 38

What are the complications of RAI treatment?

Answer 38

Initial worsening of sx/thyroid storm (rare) | Small increased risk of thyroid cancer

Question 39

What advice should pts receiving RAI be given re. children?

Answer 39

Avoid prolonged contact w/ children for 3/52 after treatment Avoid conceiving for 6mo No effect on fertility/congenital malformations

Question 40

What are the surgical options for Thyrotoxicosis?

Answer 40

Total/sub-total thyroidectomy

Question 41

When is surgical management indicated?

Answer 41

When drug therapy/RAI have failed or are contraindicated If there is a suspicion of malignancy If there is a large, toxic goitre

Question 42

What are the potential post-op complications of surgical management for Thyrotoxicosis?

Answer 42

Haematoma causing asphyxia (emergency removal of sutures required) Hypothyroidism (10%) Hypocalcaemia (transient, due to hypoparathyroidism) Vocal cord paresis (damage to recu larnygeal)