hypothyroidism W6 Flashcards

1
Q

TFT (thyroid function tests) in primary hypothyroidism?

A

increased TSH, decreased FT4 (free T4)

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2
Q

primary hypothyroidism and gender?

A

more common in women

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3
Q

symptoms of hypothyroidism

A

tired
weight gain, puffy eyes and skin
feeling cold
slow heart rate
constipation
dry hair and skin
heavy periods
hyperlipidaemia
enlarged thyroid (goitre)

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4
Q

T4 name?

A

thyroxine

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5
Q

when shouldn’t patients be treated with thyroxin even if they have symptoms of hypothyroidism?

A

if they have normal TFTs

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6
Q

common causes of primary hypothyroidism?

A

Hashimoto’s thyroiditis (autoimmune disease)
iatrogenic (post surgery or radioactive iodine)
spontaneous atrophic
temporary thyroiditis

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7
Q

Derbyshire neck?

A

iodine deficiency leads to fall in T4 causing increase in TSH which stimulates hypertrophy (growth) of the thyroid gland

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8
Q

treatment of hypothyroidism?

A

levothyroxine (synthetic form of thyroxine)
once daily
half life is 7 days
100mcg (may be greater with heavier patients)
low T4 and high TSH is enough for diagnosis, no need for more tests

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9
Q

levothyroxine timing of dose?

A

take in early morning before breakfast

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10
Q

monitoring of hypothyroidism therapy?

A

annual TFTs once stable
if dose change, wait at least 6 weeks before repeating TFTs.

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11
Q

medications that impair levothyroxine absorption?

A

proton pump inhibitors (omeprazole/lansoprazole)
H2 antagonists (eg ranitidine)
iron, calcium, aluminium
don’t take T4 <4hrs after these

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12
Q

when might T4 requirement be increased?

A

if patient starts oestrogen (OCP/HRT) or anticonvulsants

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13
Q

OCP?

A

oral contraceptive pills

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14
Q

subclinical hypothyroidism TFT patterns?

A

TSH raised, FT4 normal

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15
Q

explanation for subclinical hypothyroidism TFT patterns?

A

TSH is more sensitive than FT4
T4 levels fall within normal reference range
TSH respond and increase out with normal reference range

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16
Q

main cause of subclinical hypothyroidism?

A

main cause is autoimmune chronic thyroiditis

17
Q

weak evidence of adverse effects of subclinical hypothyroidism

A

lipids
BP
other CV risks
no hard evidence though

18
Q

risk factors for hypothyroidism?

A

raised TSH and positive antibodies

19
Q

secondary hypothyroidism TFT patterns?

A

low FT4, low TSH

20
Q

what is secondary hypothyroidism caused by?

A

pituitary disease