Thyroid

Question 1

How are T3 and T4 formed?

Answer 1

Iodine taken up by follicular cell, enters colloid and combines with tyrosine to form MIT and DIT

Question 2

Role of thyroid hormone

Answer 2

Increase protein synthesis, gluconeogenesis, thermogenesis, brain development, CNS activity, gut motility, increase responsiveness to neurotransmitters, increase HR and force

Question 3

Symptoms of hyperthyroidism

Answer 3

Tremor, weight loss/increased BMR, increased HR, tachycardia, AF, heat intolerance, moist itchy skin, anxiety, oligomenorrhoea, difficulty sleeping, eye symptoms, pretibial myxoedema, diarrhoea, palpitations, lid lag

Question 4

Symptoms of hypothyroidism

Answer 4

Cold intolerance, constipation, weight gain, loss of appetite, fatigue, slow reflexes, coarse sparse hair, cool skin, sleep apnoea, vitiligo

Question 5

Investigations for goitre

Answer 5

Antibodies, FNA, US, thyroid scan

Question 6

Treatment of hyperthyroidism

Answer 6

Carbimazole, PTU 1st trimester pregnancy (1-2 years)
B blockers
Surgery
Radio iodine

Question 7

Side effects of Carbimazole/PTU

Answer 7

Agranulocytosis (cough, sore throat), hepatitis with PTU

Question 8

Treatment of hypothyroidism

Answer 8

Lifelong levothyroxine (50-100mcg, lower if IHD or LVF)
Lower in elderly (25-50)

Question 9

Thyroid acropachy

Answer 9

Finger clubbing in Grave’s

Question 10

Thyroid scan in thyroiditis and in autoimmune thyroid disease

Answer 10

Thyroiditis: reduced uptake
Autoimmune: increased uptake

Question 11

Levels of TSH and T4 in subclinical hyperthyroid

Answer 11

Decreased TSH, normal T3/T4

Question 12

What leads to T4 -> T3 conversion

Answer 12

Stress, starvation, illness

Question 13

Thyroid storm

Answer 13

Tachycardia, low BP, fever, altered mental status, exaggerated reflexes, MOF

Question 14

Treatment of thyroid storm

Answer 14

Carbimazole, B blocker, Hydrocortisone, Potassium iodide, IV fluids

Question 15

Newborn thyroid screening test

Answer 15

Guthrie test day 5 (high TSH and low T4 before this)

Question 16

Is thyroid demand increased or decreased in pregnancy?

Answer 16

Increased = increase thyroxine by 25mcg

Question 17

Risks of untreated hypo/hyperthyroid in pregnancy

Answer 17

Pre-eclampsia, abortion, haemorrhage, birth problems

Question 18

HCG effect on thyroid in pregnancy

Answer 18

Behaves like TRH = increased thyroid hormones
Low TSH
If persists >20 weeks then treat

Question 19

Postpartum thyroiditis

Answer 19

Hyperthyroid then Hypothyroid

Postnatal depression

Question 20

Myxoedema coma

Answer 20

Bradycardia, T wave inversion, heart block, HF, prolonged QT
T2RF
Adrenal failure

Question 21

Progression of Grave’s

Answer 21

After 1 year, 50% burnout, 50% relapse

Question 22

Side effects of radio iodine

Answer 22

Avoid contact with kids/pregnant women
Don’t share bed
Avoid pregnancy for 6 months
Risk of hypothyroid

Question 23

Risk factors for thyroid cancer

Answer 23

Female
Lower in Afro-Caribbeans
Radiation