Thyroid disorders

Question 1

Hypothyroidism types of causes

Answer 1

1. autoimmune thyroiditis
2. iatrogenic
3. drug induced
4. iodine deficiency
5. congenital

Question 2

Autoimmune thyroiditis

Answer 2

Cell + antibody-mediated destruction of thyroid tissue

Can be either:

• Hashimoto’s thyroiditis
• Thyroid atrophy

Question 3

Iatrogenic causes of hypothyroidism

Answer 3

thyroidectomy

radioactive iodine treatment

Question 4

Name some drugs that can cause hypothyroidism

Answer 4

lithium
interferon alpha
amiodarone (an antiarrythmic)

Question 5

What is myxoedema

Answer 5

accumulation of mucopolysaccharide in subcut tissues (hypothyroidism)

Question 6

Symptoms of hypothyroidism

Answer 6

myxoedema
tiredness
weight gain
dry, rough skin
cold intolerance
mental slowness

Question 7

Ix hypothyroidism

Answer 7

raised serum TSH

serum free T4 & T3 would be low

hyponatraemia (from raised ADH levels)

anaemia

hyperlipidaemia

Question 8

Mx hypothyroidism

Answer 8

synthetic levothyroxine (T4)

Aim: normalise serum TSH concentrations. Titrate according to TSH

Thyroid function test after at least 6 weeks on a steady dose

Question 9

euthyroid

Answer 9

having a normally functioning thyroid gland

Question 10

what is Hashimoto’s thyroiditis

Answer 10

atrophic changes with regeneration –> goitre formation

TPO antibodies are present, often very high

Question 11

Tx Hashimoto’s thyroiditis

Answer 11

Levothyoxine may shrink goitre even when patient it not hypothyroid

Question 12

Which thyroid autoantibodies are present in almost all patients with autoimmune hypothyroidism?

Answer 12

thyroglobulin

thyroid peroxidase (TPO)

Question 13

what is the leading cause of hyperthyroidism?

Answer 13

Graves’ disease

Question 14

What happens in Graves’ disease?

Answer 14

IgG antibodies bind to TSH receptor stimulating thyroid hormone production

Question 15

Presentation of hyperthyroidism

Answer 15

Weight loss
Increased appetite
Irritability
Tremor
Heat intolerance
Tachycardia
AF

Question 16

Clinical features specific to Graves’

Answer 16

opthalmopathy

pretibial myxoedema (raised red lesions on front of shins)

thyroid acropachy - clubbing, swollen fingers

Question 17

Ix hyperthyroidism

Answer 17

Serum TSH is suppressed

Serum free T4 + T3 are elevated

Question 18

What antibodies are present in most Graves’?

Answer 18

thyroid stimulating immunoglobulin (TSI)

thyroid peroxidase + thyroglobulin antibodies

Question 19

Drug treatment for hyperthyroidism?

Answer 19

Thionamines e.g. carbimazole

Decrease synthesis of new thyroid hormone

1. block + replace for Graves’
2. short course to render euthyroid before other Tx
3. long term if unwilling of other Tx

Question 20

What drugs for rapid symptomatic control in hyperthyroidism?

Answer 20

Beta-blockers

As many symptoms are from sympathetic nervous system

Question 21

Further treatments for hyperthyroidism (not drugs)

Answer 21

Radioactive iodine ablation

Surgery - only if patients rendered eurothyroid

Question 22

what symptoms are specific to ophthalmic graves disease?

Answer 22

protruding eyeballs
limitation of eye movement

(lid lag + retraction could be any hyperthyroid)

Question 23

pathphy of ophthalmic graves’ disease

Answer 23

?TSH receptor antibodies bind to TSH receptors in retro-orbital connective tissue

R-O inflammation of muscles + CT behind eyes

leads to opthalmopathy, peiorbial oedema, more severe in smokers

Question 24

Mx ophthalmic Graves’ disease

Answer 24

stop smoking
correct thyroid dysfunction
artificial tears

Question 25

predisposition to thyroid autoimmunity (Graves’ disease)

Answer 25

RF: F and postpartum
HLA-DR3
Envinromental: stress, high iodine intake, smoking

Question 26

How to distinguish between benign and malignant thyroid nodules?

Answer 26

fine needle aspiration cytology

Question 27

treatment of follicular and papillary cancers?

Answer 27

thyroidectomy with neck dissection for local nodal spread

then ablative radioactive iodine

Question 28

treatment for anaplastic carcinoma and lymphoma?

Answer 28

maybe external radiotherapy

otherwise Tx is largely palliative

Question 29

how do most thyroid cancers present?

Answer 29

asymptomatic thyroid nodules

Question 30

1st sign of disease in thyroid cancer?

Answer 30

lymph-node mets

rarely bone and lung mets

Question 31

what features suggest carcinoma in a patient presenting with a thyroid nodule?

Answer 31

Hx of progressive increase in size
hard and irregular nodule
enlarged lymph nodes on examination

Question 32

what is myxoedema coma

Answer 32

loss of brain function from severe, longstanding low level of thyroid hormone in the blood (hypothyroidism)