Thyrotoxicosis (E&M)

Question 1

Define thyrotoxicosis.

Answer 1

Symptoms caused by excessive circulation of thyroid hormones

Caused by conditions that lead to hyperthyroidism

Question 2

What are some causes of thyrotoxicosis? (6)

Answer 2

• Grave’s disease
• toxic multinodular goitre (Plummer’s)
• toxic adenoma
• malignancy
• amiodarone-induced
• thyroiditis - de Quervain’s, postpartum, drug-induced, acute/infectious

Question 3

What groups does thyrotoxicosis happen more commonly in? (2)

Answer 3

• F>M
• Grave’s disease present at 20-30y

Question 4

What is Grave’s disease?

Answer 4

Presence of TSH-Rc stimulating autoantibodies –> hyperthyroidism due to loss of negative feedback

Absence of eye signs does not exclude diagnosis

Question 5

What are some types of thyroid malignancy causing thyrotoxicosis? (5)

Answer 5

• papillary (60%)
• follicular (25%)
• medullary (5%)
• lymphoma (5%)
• anaplastic (rare)

Question 6

What is de Quervain’s thyroiditis?

Answer 6

Viral thyroiditis - painful dysphagia and pyrexia

Hyperthyroid –> hypothyroid –> euthyroid

Question 7

What is a thyroid storm?

Answer 7

Acute exacerbation of hyperthyroidism that results in a life-threatening hypermetabolic state

Question 8

What may a thyroid storm be triggered by? (3)

Answer 8

• surgery
• trauma
• infection

Question 9

What type of diabetes can trigger thyroid storm?

Answer 9

T1DM - DKA as it is acute stress on body

Question 10

What are the clinical features of a thyroid storm? (6)

Answer 10

• hyperpyrexia >41C
• hypertension
• tachycardia
• jaundice
• severe N&V
• confusion and agitation/syncope

Question 11

How do we manage a thyroid storm? (4)

Answer 11

• high-dose propylthiouracil (followed by potassium iodide in the form of Lugol’s iodine 6h later)
• hydrocortisone
• IV propranolol
• IV digoxin

ABCD - ATD (PTU), BB, Corticosteroid, Digoxin

Question 12

What is the most common cause of hyperthyroidism in countries with sufficient iodine intake?

Answer 12

Grave’s disease

Question 13

What are the clinical features of general hyperthyroidism? (14)

Answer 13

• weight loss (despite increased appetite)
• heat intolerance
• palpitations
• tachycardia
• tremor
• restlessness
• anxiety
• sweating
• diarrhoea
• oligo/amenorrhoea
• loss of libido
• hair thinning
• onycholysis (nail separates from bed)
• lid lag (eyelid lags behind eye’s descent as patient watches your finger descend)

Question 14

What are some Grave’s disease specific clinical features? (3)

Answer 14

• exophthalmos
• pretibial myxoedema
• thyroid acropachy - clubbing of fingernails

Question 15

What are the two kinds of goitre (enlarged thyroid)?

Answer 15

• diffuse goitre - autoimmune (Grave’s, Hashimoto’s), endemic (iodine deficiency), acute thyroiditis (de Quervain’s), physiological (pregnancy, puberty)
• nodular goitre - multinodular (usually euthyroid), fibrotic goitre, solitary nodule, discrete nodule in MNG

Question 16

What are some risk factors for hyperthyroidism? (7)

Answer 16

• Fx autoimmune thyroid disease
• female sex
• tobacco use
• high iodine intake
• lithium therapy
• radiation
• stress

Question 17

What are the first-line investigations for hyperthyroidism? (6)

Answer 17

• TFTs - TSH, T3, T4
• autoantibodies (anti-TSH receptor in Grave’s, anti-TPO in Hashimoto’s, anti-TG)
• serum calcium
• thyroid ultrasound
• fine needle aspiration for neck lumps
• radioactive iodine uptake scan

Question 18

What would TFTs show in primary hyperthyroidism?

Answer 18

• high T3/T4
• low TSH

Question 19

If anti-TSH receptor antibody is present, what does it mean?

Answer 19

Grave’s disease

(anti-TSH receptor antibodies very sensitive and specific for Grave’s)

(anti-TPO positive in 70%)

Question 20

What does diffuse uptake throughout enlarged gland on radioactive iodine uptake scan mean?

Answer 20

Grave’s disease

Question 21

What does multinodular gland with single hot nodule, patchy uptake on radioactive iodine uptake scan mean?

Answer 21

Toxic multinodular goitre

Treated with radioiodine therapy

Question 22

What does diffuse uptake with single cold nodule on radioactive iodine uptake scan mean?

Answer 22

Thyroid cancer

Question 23

What does no uptake on radioactive iodine uptake scan mean?

Answer 23

de Quervain’s (viral) thyroiditis

Or other thyroiditis (drug-induced, postpartum etc)

Question 24

What is the disease course and presentation of de Quervain’s viral thyroiditis like?

Answer 24

Initially hyperthyroid and have painful tender goitre and dysphagia after a viral (flu-like) illness, then hypothyroid after, then resolves –> euthyroid

Question 25

How is de Quervain's (viral) thyroiditis managed?

Answer 25

Self-limiting, and can be managed conservatively e.g. NSAIDs

Question 26

How do thyroid cancers show up on scintigraphy?

Answer 26

Cold spots

Question 27

What are the different types of thyroid cancers? (5)

Answer 27

- papillary carcinoma - lymph node metastasis predominate - follicular adenoma - solitary thyroid nodules - follicular carcinoma - vascular / capsular invasion - medullary carcinoma - calcitonin raised, familial, lymphatic and haematogenous spread - anaplastic carcinoma - elderly females, local invasion, resection

Question 28

How do we manage symptoms in hyperthyroidism?

Answer 28

Propranolol (beta blocker) - for tachycardia and tremor

Question 29

What different definitive managements are there for hyperthyroidism? (3)

Answer 29

- anti-thyroid drugs - carbimazole (inhibits TPO), propylthiouracil, potassium iodide - radioactive iodine ablation - destruction of thyroid tissue via radioactive iodine - thyroid surgery (total thyroidectomy)

Question 30

What is the first-line management for Grave's disease?

Answer 30

Carbimazole (inhibits TPO) - give for 12-18 months then reassess

Question 31

When is carbimazole (anti-thyroid drug for Grave's) contraindicated?

Answer 31

Early pregnancy

Question 32

When is propylthiouracil the treatment of choice for Grave's disease? (2)

Answer 32

- first trimester pregnancy - thyroid storm

Question 33

What are some side effects of anti-thyroid drugs (carbimazole and propylthiouracil)?

Answer 33

Agranulocytosis + neutropenia- seek urgent medical attention if infection developed so FBC can be measured

Question 34

When do we do radioactive iodine ablation for hyperthyroidism?

Answer 34

If resistant to anti-thyroid drugs | Also for toxic multinodular goitre

Question 35

What 2 conditions is radioactive iodine ablation the definitive treatment for?

Answer 35

- Grave's disease - toxic multinodular goitre

Question 36

What do patients need to know about radioactive iodine ablation?

Answer 36

- cannot conceive for 6 months - avoid contact with pregnant women or children

Question 37

How do we manage a thyroid storm? (4)

Answer 37

- high-dose propylthiouracil (followed by potassium iodide in the form of Lugol's iodine 6h later) - hydrocortisone - IV propranolol - IV digoxin

Question 38

How do we treat toxic multinodular goitre?

Answer 38

Radioiodine therapy

Question 39

How is de Quervain's (viral) thyroiditis managed?

Answer 39

Self-limiting, and can be managed conservatively e.g. NSAIDs

Question 40

When is potassium iodide used in hyperthyroidism?

Answer 40

Thyroid storm Shrink thyroid prior to surgery

Question 41

What are some complications of hyperthyroidism? (5)

Answer 41

- high output cardiac failure - AF - sight-threatening complications of Grave's orbitopathy - hyperlipidaemia - myxoedema coma

Question 42

What can thyroid hormone over-replacement lead to?

Answer 42

Bone loss and tachycardia