thyroid gland

Question 1

functions of thyroid hormone

Answer 1

raise metabolic rate
promote thermogenesis
increases hepatic gluconeogenesis
net increase in proteolysis
net increase in lipolysis
critical for growth
essential for brain development in utero

Question 2

where does the thyroid gland lie vertebral level

Answer 2

C5-T1

Question 3

what are the thyroid hormones called

Answer 3

triiodothyromine T3
thyroxine T4

Question 4

what are the two cell types in thyroid gland

Answer 4

C (clear) cells
follicular cells

Question 5

what do follicular cells do

Answer 5

support thyroid hormone synthesis and surround hollow follicles
make thyroglobulin- rich in tyrosine residues
then into colloid and in colloid, tyrosine residues and iodine combine to form thyroid hormones

Question 6

how is T3 made

Answer 6

1 iodine + tyrosine makes MIT
2 iodine + tyrosine makes DIT

MIT + DIT = T3

Question 7

how is T4 made

Answer 7

1 iodine + tyrosine makes MIT
2 iodine + tyrosine makes DIT

DIT +DIT = thyroxine T4

Question 8

are T 3 and T4 inactive or active

Answer 8

mainly bound to plasma proteins and inactive. they are lipid soluble. only 0.2% are active

there is more of T4 as it has longer half life but T3 binds more to TH receptors so is more active

Question 9

hyperthyroidism can be caused by

Answer 9

primary-
graves disease
toxic multinodular goitre
toxic adenoma

secondary-
pituitary adenoma

Question 10

hypothyroidism causes

Answer 10

primary-
congenital
hashimotos thyroiditis- autoimmune
iatrogenic
deficiency in dietary iodine
pst subacute thyroiditis

secondary-
pituitary adenoma
craniopharyngioma
post pituitary surgery or radiotherapy

subclinical- risk of overtreating, normal T3 and T4 but abnormal TSH

Question 11

hypothyroidism signs and symptoms

Answer 11

weight gain
lethargy
feeling cold
constipation
heavy periods
dry skin/hair
bradycardia
slow reflexes
goitre
severe- puffy face, large tongue, hoarseness, coma

Question 12

hyperthyroidism signs and symptoms

Answer 12

weight loss
anxiety/irritability
heat intolerance
bowel frequency
light periods
sweaty palms
palpitations
hyperreflexia/tremors
goitre
thyroid eye symptoms/signs

Question 13

tests for hypothyroidism

Answer 13

TFTs- TSH and T4
FBC
glucose and HbA1C

Question 14

management for hypothyroidism

Answer 14

levothyroxine - first thing in morning empty stomach
measure TFTs every month until TSH level stabilises then once a year

Question 15

hypothyroidism in pregnancy managment

Answer 15

empirical dose
regular monitoring
aim for TSH lower half of normal
post natal reduce levothyroxine to prepregnancy dose 2 weeks after
recheck 2-3 months post pregnancy

Question 16

management for hyperthyroidism

Answer 16

antithyroid drugs - carbimazole or propylthiouracil 1
radioiodine 2
surgery 3

Question 17

subclinical hyperthyroidism

Answer 17

normal T3 and T4
TSH suppressed
risk of bone density decreases
AF risk

Question 18

single nodular thyroid test

Answer 18

US first line
FNA if suspicious
risk of malignancy if a child, previous H+N radiation, pain
TFTs

Question 19

thyroid cancer types

Answer 19

papillary, lymphoma, anaplastic, medullary and follicular

Question 20

papillary thyroid cancer

Answer 20

commonest
multifocal
good prognosis

Question 21

follicular thyroid cancer

Answer 21

usually single lesion
metastases to lung and bone
good prognosis if resectable
poorer if <16yo or >55yo

Question 22

management thyroid cancer

Answer 22

near total thyroidectomy
high dose radioiodine
thyroxine long term
follow up- whole body iodine scanning following 2- 4 weeks of thyroxine withdrawal
biopsy

Question 23

thyroiditis causes

Answer 23

inflammation of thyroid gland
autoimmune disorders
viral infections
radiation therapy

Question 24

graves disease

Answer 24

autoimmune disease
F>M
TSH receptor antibodies
between 20 and 40
bulging eyes (exopthalmus) or eye irritation
causes hyperthyroidism

Question 25

carbimazole complication

Answer 25

Agranulocytosis (acute lowering of the white cell count) needs to be suspected and acted upon urgently.

Agranulocytosis may occur at any stage during treatment with Carbimazole and without warning. Patients are advised to immediately report symptoms of infection, such as a sore throat or fever, so that a full blood count test may be arranged.