3- hyperthyroidism & hypothyroidism

Question 1

what is
a) primary thyroid problem
b) secondary thyroid problem

Answer 1

a) disease primarily affecting thyroid gland (can be goitrous or goitre)
b) not disease of thyroid itself, disease of hypothalamic or pituitary disease

Question 2

what are the investigations for thyroid problems?

Answer 2

• blood tests
• thyroid stimulating hormone (TSH)
• free hormones (T3&T4)

Question 3

what are findings for primary hypothyroidism?

Answer 3

• low T3&T4 (since thyroid not - making enough)
• also has high TSH (in response to low T3&4)

Question 4

what is findings of primary hyperthyroidism?

Answer 4

• high T3 & T4 (since thyroid making too much likely through auto-antibodies)
• low TSH in response (to try and make less stimulation so less T3&4 produced)

Question 5

what is findings of secondary hypothyroidism?

Answer 5

• T3 & T4 low (since hypo)
• this should mean that TSH is high since feedback mechanism but problem with pituitary or hypothalamus so TSH low or inappropriately normal

Question 6

what are findings for secondary hyperthyroidism?

Answer 6

• T3 & T4 high (since hyper)
• should mean TSH low but since problem with hypothalamus or pituitary TSH high or inappropriately normal

Question 7

what is common presentation of hypothyroidism?

Answer 7

= more in white female

• coarse, sparse hair
• dull expressionless face
• periorbital puffiness
• pale cool skin, doughy
• hypercarotenaemia
• pitting oedema
• cold intolerance
• maybe vitiligo

Question 8

what are most common causes of primary hypothyroidism? (goitrous, non-goitrous)

Answer 8

goitrous
- hashimoto’s thyroiditis (autoimmune)
- iodine deficiency
- also drug induced (amiodarone)

non-goitrous
- atrophic thyroiditis (autoimmune)
- also post radiotherapy

Question 9

what is subclinical hypothyroidism & hyperthyroidism?

Answer 9

hypothyroidism = where TSH high but T3 & T4 in normal ranges

hyperthyroidism = where TSH low but normal T3&T4

→they won’t have any clinical symptoms but could be at risk of developing hypothyroidism in future

• will only treat if subclinical hyperthyroidism with symptoms of osteoporosis or AF

Question 10

when can you get self limiting primary hypothyroidism?

Answer 10

• first 6-12 months postpartum
• withdrawal of anti-thyroid drugs

Question 11

what are causes of secondary hypothyroidism?

Answer 11

= problem in pituitary or hypothalamus (will cover more in pituitary lecture)

Question 12

what is hashimoto’s thyroiditis?

Answer 12

autoimmune destruction of thyroid gland & reduced thyroid hormone production

Question 13

what are steps to diagnosis of hashimoto’s thyroiditis?

Answer 13

• will find low T3&T4 and high TSH
• then check antibodies = thyroid perioxidase antibody (TPO). if positive defo hashimoto’s

Question 14

what are some extra clinical features of hypothyroidism?

Answer 14

loads!! - basically down regulates everywhere

• cardiac = reduce HR, worse heart failure
• metabolic = hyperlipidaemia
• GI = constipation
• resp = deep, hoarse voice
• neurological = low mood, muscle stiffness
• reproductive = heavy periods

Question 15

what is the most important thyroid antibody to test for hashimoto’s?

Answer 15

TPO = thyroid peroxidase

Question 16

what is hypothyroidism management?

Answer 16

in young patients = 50-100 micrograms levothyroxine

in old patients = 25-50 micrograms levothyroxine (start low and adjust 4 weekly as don’t want to fluctuate cardiac rate since make arrhythmia)

Question 17

how do you monitor amount of treatment to give for primary and secondary hypothyroidism?

Answer 17

monitor primary hypothyroidism with TSH - when normalises, you’re giving good levothyroxine

monitor secondary hypothyroidism by titrating dose to fT4 level

Question 18

what is myxoedema coma? treatment?

Answer 18

presentation of severe hypothyroidism (high mortality)

• typically elderly women with longstanding unrecognised or untreated hypothyroidism
• will have low voltage and slow HR on ECG, type 2 resp failure (slow breathing)

treat = intensive care, cardiac monitor for arrhythmias, antibiotics (as often triggered by infection), hydrocortisone (helps kidney stuff)

Question 19

what is thyrotoxicosis?

Answer 19

clinical manifestation of hyperthyroidism - when tissues exposed to excess thyroid

Question 20

what are some signs & symptoms of hyperthyroidism?

Answer 20

loads again! basically everything sped up. increased metabolic rate with increase glucose release & uptake to maintain higher metabolism

• cardiac = palpitations, AF
• sympathetic symptoms = tremor, sweating
• CNS = anxiety, nervousness, irritability
• GI = frequent, loose bowel
• vision
• hair = brittle, thin hair, rapid fingernail growth
• reproductive = lighter menstruation
• muscles
• thermogenesis = intolerance to heat

Question 21

what are main causes of primary hyperthyroidism?

Answer 21

excess thyroid stimulation:
- graves disease (autoimmune)
- thyroid cancer etc

thyroid nodules with autonomous function
- toxic multinodular goiter (especially elderly)

Question 22

what are causes of secondary hyperthyroidism?

Answer 22

*thyroid making too many hormones but not thyroid fault

• post partum or drugs e.g. amiodarone causing thyroiditis (inflammation)
• overtreatment levothyroxine = giving too much exogenous thyroid hormones
• ectopic thyroid tissue making T3 &T4 e.g. metastatic thyroid carcinoma

Question 23

what is graves disease?

Answer 23

= autoimmune condition causing primary hyperthyroidism

Question 24

what is typical presentation of graves disease?

Answer 24

• more in younger people (smoking can increase risks so must stop!)
• has smooth large goitre
• pretibial myxoedema (big rashes on shins)
• thyroid acropachy (clubbing)
• graves eye disease

Question 25

what are steps to diagnosis of graves disease?

Answer 25

- original labs will show high T3&T4 with low TSH - next check TRAb antibodies (TSH receptor antibody) = if positive then defo graves

Question 26

what is graves eye disease? management?

Answer 26

= they're like very big eye bulge, you can also see white of eye like between eye lids - occurs in 20% of graves patients and more risk in smoking - can be unilateral or bilateral management - choose between anti-thyroid drugs, radioiodine, surgery

Question 27

what is nodular thyroid disease? management?

Answer 27

2nd most common cause of overactive thyroid - more in older people - can feel nodules on thyroid gland (graves goitre smooth) management = doesn't respond to anti-thyroid drugs so radioiodine or surgery

Question 28

what are steps to diagnose nodular thyroid disease?

Answer 28

- increased T3&T4 with decreased TSH - negative TRAb antibody (since not graves) - scintigraphy = nuclear uptake scan - thyroid ultrasound

Question 29

what is thyroid storm?

Answer 29

= extreme hyperthyroidism - it's a medical emergency - often in hyperthyroid patients with acute infection or illness

Question 30

what are treatment options for hyperthyroidism?

Answer 30

1. antithyroid drugs - carbimazole (1st line) or propylthiouracil (PTU) 2. radioiodine (contraindicated if graves eye disease) 3. surgery - thyroidectomy (will then need levothyroxine replacement lifelong) *can also give beta blockers, propranolol, to help symptoms

Question 31

what are side effects of antithyroid drugs?

Answer 31

- generally well tolerated, could get allergic rash or liver stuff but important one is agranulocytosis = rare but severe. need to safety net for fever or sore throat (will get blood test to show if problem with bone marrow)

Question 32

what is non-thyroidal illness?

Answer 32

= sick euthyroid syndrome - commonly encountered in people unwell in hospital - basically illness can affect thyroid function. usually just get checked again once recovered from illness to confirm just sick thyroid and not genuine problem - TSH usually suppressed but rises in recovery