Endocrine - Hyperthyroidism

Question 1

What is Thyrotoxicosis?

Answer 1

Excessive quantity of thyroid hormones

Question 2

What is primary hyperthyroidism?

Answer 2

Thyroid pathology causing excessive thyroid hormone

High T3/4
Low TSH

Question 3

What is secondary hyperthyroidism?

Answer 3

Pathology in hypothalamus or pituitary

High TSH
High T3/4

Question 4

What is subclinical hyperthyroidism?

Answer 4

T3 and T4 are normal

TSH is low

Question 5

What is Grave’s disease?

Answer 5

TSH receptor autoantibodies

Stimulates TSH receptors to release thyroid hormones

Question 6

What is a toxic multinodular goitre?

Answer 6

AKA Plummer’s disease

Nodules develop on thyroid gland causes continuous production of excessive thyroid hormones

Question 7

What causes exophthalmos in Grave’s disease?

Answer 7

Cytokine production due to autoantibodies

Cytokines stimulate synthesis of glycosaminoglycans (GAGs) by fibroblasts

GAGs attract water

Causes periorbital oedema, proptosis and swelling extraocular muscles

Question 8

What is pretibial myxoedema caused by?

Answer 8

Deposits of glycosaminoglycans under skin on anterior aspect of the leg

Specific to Grave’s disease reaction to TSH receptor antibodies

Can also occur in Hashimoto’s thyroiditis but much rarer

Question 9

What can cause hyperthyroidism?

Answer 9

Grave’s disease
Thyroiditis
Solitary toxic thyroid nodule
Toxic multinodular goitre

Question 10

What are some causes of thyroiditis?

Answer 10

De Quervain’s thyroiditis
Hashimoto’s thyroiditis
Postpartum thyroiditis
Drug-induced thyroiditis

Question 11

How does hyperthyroidism present?

Answer 11

Anxiety and irritability
Sweat and heat intolerance
Tachycardia
Weight loss
Fatigue
Insomnia
Sexual dysfunction

Question 12

What specific features are caused by Grave’s disease?

Answer 12

Diffuse goitre
Exophthalmos
Pretibial myxoedema
Thyroid acropachy (hand swelling and finger clubbing)

Question 13

What is a solitary toxic thyroid nodule?

Answer 13

Single abnormal thyroid nodule releases excessive thyroid hormone

Nodules are benign adenomas

Surgical removal to treat

Question 14

What is De Quervain’s Thyroiditis?

Answer 14

AKA subacute thyroiditis

Condition causing temporary inflammation of the thyroid gland

Three phases:
- Thyrotoxicosis
- Hypothyroidism
- Return to normal

Question 15

What does the initial thyrotoxic phase involve?

Answer 15

Excessive thyroid hormones
Thyroid swelling and tenderness
Flu-like illness
Raised inflammatory markers (CRP and ESR)

Question 16

How do you treat De Quervain’s thyroiditis?

Answer 16

NSAIDs
Beta blockers for symptoms of hyperthyroidism
Levothyroxine for symptoms of hypothyroidism

Question 17

What is a thyroid storm/ thyrotoxic crisis?

Answer 17

Severe presentation of hyperthyroidism with
- Fever
- Tachycardia
- Delirium

May need fluid resuscitation, anti-arrhythmics and beta blockers

Question 18

How do you manage hyperthyroidism?

Answer 18

First-line
Carbimazole 12-18 months

After 4-8 weeks thyroid levels will be normal

Carbimazole is continued on maintenance and either:
- Carbimazole dose titrated to maintain normal levels
- Higher dose to block all production and levothyroxine given (block and replace)

Second-line
Propylthiouracil

Small risk of severe liver reactions so carbimazole is preferred

Question 19

What can carbimazole cause?

Answer 19

Acute pancreatitis

Question 20

What can carbimazole and propylthiouracil cause?

Answer 20

Agranulocytosis with extremely low WBC

Sore throat key sign of agranulocytosis

Question 21

How does radioactive iodine treatment work?

Answer 21

Thyroid takes up radioactive iodine

Emitted radiation destroys proportion of thyroid cells

Reduction in number of cells decreasing thyroid production

Remission can take 6 months

Question 22

Why do you give long-term levothyroxine after radioactive iodine treatment?

Answer 22

Thyroid becomes underactive

Question 23

What strict rules are there with radioactive iodine treatment?

Answer 23

• Women must not be pregnant or breastfeed and get pregnant within 6 months of teatment
• Men cannot father children within 4 months
• Limit contact with people after the dose

Question 24

Why is propranolol preferred to bisoprolol for treating adrenaline-related symptoms of hyperthyroidism?

Answer 24

Non-selectively blocks adrenergic activity

Bisoprolol is more selective

Particularly useful for thyroid storm management

Question 25

What is the final treatment option for hyperthyroidism?

Answer 25

Thyroidectomy

Patients require life-long levothyroxine after