Clinical Thyroid Disease Flashcards
GIve 4 examples of thyroid disease.
- Hyperthyroidism
- Hypothyroidism
- Goitre
- Thyroid Cancer
What can hypothyroidism present with?
- fatigue/lethargy
- cold intolerance
- weight gain
- non-specific weakness, athralgia/myalgia
- constipation
- heavy periods
- dry skin/hair
- oedema
- bradycardia
- slow reflexes
- goitre
- severe (puffy face, large tongue, hoarseness, coma)
What can hyperthyroidism present with?
- anxiety/irritability
- weight loss
- heat intolerance
- bowel frequency
- light periods
- sweaty palms
- palpitations
- hyperreflexia/tremors
- goitre
- thyroid eye symptoms/signs
What will TFT results for primary hypothyroidism be?
- raised TSH
- low T4
- low T3
What will TFT results for subclinical (compensated) hypothyroidism?
- raised TSH
- normal T4
- normal T3
What will TFT results for secondary hypothyroidism be?
- low TSH
- low T4
- low T3
What is the prevalence of hypothyroidism?
commonest endocrine condition after diabetes
- 1.9% in women
- 0.1% in men
How many people are affected by subclinical hypothyroidism?
5%
- 10% of women over the age of 60
What are the congenital causes of hypothyroidism?
Developmental
- agenesis/maldevelopment
Dyshormonogenesis
- trapping/organification/dehalogenase
What are the acquired causes of primary hypothyroidism?
autoimmune thyroid disease
- hashimotos/atrophic
iatrogenic
- postoperative/post-radioactive iodine
- external RT for head and neck cancers
- antithyroid drugs, amiodarone, lithium, interferon
chronic iodine deficiency
post-subacute thyroiditis
- post partum thyroiditis
What are the causes of secondary/tertiary hypothyroidism?
pituitary/hypothalamic damage
- pituitary tumour
- craniopharyngioma
- post pituitary surgery or radiotherapy
- sheehan’s syndrome
- isolated TRH deficiency
How should hypothyroidism be investigated?
blood tests
- TFTs: TSH & free T4
- thyroid peroxidase antibodies (TPA)
How should hypothyroidism be treated?
- Levothyroxine (T4) tablets
- (Liothyronine (T3))
- Combination of T4 & T3: no benefit in studies
- Initial dose Levothyroxine 50mcg/day, increase after 2 weeks to 100mcg
- Increase dose until TSH normal (or fT4 in normal range in secondary)
- Half-life of T4 is 7 days
- After stabilisation annual testing of TSH
- Compliance
How should hypothyroidism be treated in ischaemic heart disease?
Start at lower dose 25mcg and increase cautiously; risk of precipitating angina
How should hypothyroidism be treated in pregnancy?
Most patients need an increase in LT4 dose
How should hypothyroidism be treated in postpartum thyroiditis?
Trial withdrawal and measure TFT’s in 6 weeks
How should hypothyroidism be treated in myxoedema coma?
Very rare emergency, may need IV T3 (steroid)
When should treatment for subclinical hypothyroidism be considered?
- Consider treatment TSH > 10
- TSH > 5 with positive thyroid antibodies
- TSH elevated with symptoms (Trial of therapy for 3 to 4 months and continue if symptomatic improvement)
- If planning pregnancy or already pregnant
What are the risks of treatment of subclinical hypothyroidism?
- Osteopenia
- AF
What is the risk of thyroid disease progression with positive TAb only?
1.3%/year
What is the risk of thyroid disease progression with raised TSH only?
1.6%/year
What is the risk of thyroid disease progression with raised TSH and positive TAb?
2.3%/year
What can inadequately treated hypothyroidism lead to during pregnancy?
increased foetal loss and Lower IQ
What should be done for hypothyroid individuals when they become pregnant?
- Increase LT4 dose by about 25% and monitor closely
- Aim to keep TSH in low normal range (<2.5mU/l) and FT4 in high normal range
