Thyroid Disease

Question 1

describe the hypothalamus-pituitary-thyroid axis

Answer 1

hypothalamus secretes TRH
TRH stimulates anterior pituitary to release TSH
TSH acts on thyroid to release thyroxine (T4) and triiodothyronine (T3)
T3 + T4 act on body organs

Question 2

what is primary hypothyroidism

Answer 2

problem with the thyroid gland itself causing it to be underactive e.g autoimmune disease

Question 3

what is secondary hypothyroidism

Answer 3

problem with the pituitary gland

Question 4

symptoms of hypothyroidism

Answer 4

bradycardia
fatigue
cold intolerance
constipation
weight gain
menorrhagia 
dry hair, pale skin

Question 5

thyroid function tests primary hypothyroidism

Answer 5

High TSH

Low T3/T4

Question 6

thyroid function tests secondary hypothyroidism

Answer 6

Low TSH

Low T3/T4

Question 7

most common cause of hypothyroidism in the developed world

Answer 7

Hashimotos thyroiditis

primary hypothyroidism

Question 8

what is Hashimotos thyroiditis

Answer 8

autoimmune hypothyroidism

- associated with other autoimmune conditions: T1DM, pernicious anaemia, Addisons

Question 9

antibodies in Hashimotos

Answer 9

anti-TPO (thyroid peroxidase)

Question 10

what cells mediate Hashimotos

Answer 10

T cells

Question 11

cells seen in biopsy of Hashimotos

Answer 11

Askanazy cells

Question 12

most common cause of hypothyroidism in developing world

Answer 12

Iodine deficiency

Question 13

what is atrophic thyroiditis

Answer 13

diffuse lymphocytic infiltration of thyroid gland leading to

• hypothyroidism
• atrophy
• goitre

Question 14

what is atrophic thyroiditis

Answer 14

diffuse lymphocytic infiltration of thyroid gland leading to

• hypothyroidism
• atrophy
• goitre

Question 15

painful goitre + raised ESR

Answer 15

subacute thyroiditis

Question 16

thyroid function tests in subclinical hypothyroidism

Answer 16

High TSH
Normal T3/T4
- patient on way to developing hypothyroidism but still has normal thyroxine levels

Question 17

what is Sheehan syndrome

Answer 17

hypopituitarism following child birth due to hypovolaemic shock+ ischaemic necrosis

• massive post partum haemorrhage
• agalactorrhoea
• hypothyroidism

Question 18

what is Riedel thyroiditis

Answer 18

fibrous tissue replacing normal thyroid parenchyma

• painless goitre
• hypothyroidism

Question 19

treatment of hypothyroidism

Answer 19

Levothyroxine (T4 replacement)

Question 20

starting dose of levothyroxine

Answer 20

25mcg OD and slowly titrated in patients >50 or those with cardiac disease
50-100mcg in all other patients

Question 21

what happens to the dose of levothyroxine in pregnancy

Answer 21

increase by 25mcg

Question 22

thyroid function tests in poor levothyroxine compliance

Answer 22

High TSH

Normal T3/T4

Question 23

side effects of levothyroxine

Answer 23

hyperthyroidism in over treatment
reduced bone mineral density
Atrial fibrillation
Worsening of angina

Question 24

what mood stabilising drug can cause hypothyroidism

Answer 24

lithium

Question 25

what is myxoedema coma

Answer 25

medical emergency of hypothyroidism | - precipitated by illness/drugs

Question 26

how does myxoedema coma present

Answer 26

confusion, hypothermia, bradycardia, hypotension, hypoglycaemia

Question 27

symptoms of hyperthyroidism (thyrotoxicosis)

Answer 27

``` tachycardia/ palpitations heat intolerance dirarrhoea weight loss amenorrhoea tremor insomnia ```

Question 28

symptoms of hyperthyroidism (thyrotoxicosis)

Answer 28

``` tachycardia heat intolerance dirarrhoea weight loss amenorrhoea tremor insomnia ```

Question 29

thyroid function tests hyperthyroidism

Answer 29

Low TSH | High T3/T4

Question 30

Most common cause of hyperthyroidism

Answer 30

Grave's disease

Question 31

antibodies in grave's disease

Answer 31

Thyroid stimulating hormone receptor antibodies (TRAB)

Question 32

Additional features of Grave's disease

Answer 32

EYE DISEASE - proptosis - exophthalmos - lid lag Pre-tibial myoxedma

Question 33

treatment of hyperthyroidism

Answer 33

carbimazole beta blockers - symptomatic relief radio iodine / surgery can also be used

Question 34

important side effect of carbimazole

Answer 34

agranulocytosis

Question 35

single hot nodule on isotope scan

Answer 35

toxic adenoma

Question 36

what is a toxic adenoma

Answer 36

solitary thyroid nodule causing hyperthyroidism | - secretes T3

Question 37

Treatment of toxic adenoma

Answer 37

radioiodine

Question 38

globally reduced uptake on isotope scan

Answer 38

subacute thyroiditis (De Quervians) - self limiting viral infection - painful goitre - fever

Question 39

patchy uptake on isotope scan

Answer 39

toxic multi nodular goitre

Question 40

what cardiac drug can cause hyperthyroidism

Answer 40

amiodarone

Question 41

what drug can cause hyperthyroidism

Answer 41

amiodarone

Question 42

thyroid function tests in sick euthyroid

Answer 42

Low TST Low T3/T4 - Common in hospital patients - Resolves upon recovery from systemic illness

Question 43

what is a thyroid storm

Answer 43

life threatening emergency associated with hyperthyroidism | - precipitated by surgery, contrast CT, acute illness, trauma

Question 44

symptoms of thyroid storm

Answer 44

``` temperature >38.5 seizures vomiting HTN confusion + agitation jaundice ```

Question 45

treatment of thyroid storm

Answer 45

IV propanolol IV dexamethasone Antithyroid drugs e.g. methimazole

Question 46

What is thyroid acropachy

Answer 46

triad of: - finger clubbing - soft tissue swelling of hands + feet - periosteal new bone formation

Question 47

what condition is thyroid acropachy seen in

Answer 47

Grave's disease

Question 48

Modifiable risk factor for reducing likelihood of developing thyroid eye disease

Answer 48

smoking