Thyroid Flashcards
What is thyrotoxycosis?
The clinical effect of increased levels of T4. Usually from a hyperfunctioning thyroid gland.
Symptoms of thyrotoxicosis
Diarrhoea increased appetite but weight loss palpitations Tremor heat intolerance + sweating Irritability Oligomenorrhoea ± infertility
What signs might you find on examination of someone with hyperthyroidism / thyrotoxicosis
hands - fast ± irregular pulse. warm skin, fine tremor, palmar erythema
face - thin hair, lid lag, lid retraction
neck - goitre or nodules
Specific to Graves (antibodies to the TSH receptor)
- exophthalmos, opthalmoplegia, eye discomfort / grittiness, photophobia and reduced visual acuity
- pre-tibial myxoedema
Investigations
check for other causes of sweating / palpitations / afib - infection ( pneumonia, UTI), do ECG if they have irregular pulse.
TFTS
- low TSH ( not needed because the gland is overactive on its own or thanks to the grave’s antibodies)
- elevated T4 and T3
- elevated calcium and LFTs
further investigations -> look for antibodies to the TSH receptor ( graves)
- isotope scan - increased uptake in graves, reduced uptake in thyroiditis ( because the thyroid isn’t functionally using iodine
-
Epidemiology of Graves
accounts for 60% of thyrotoxicosis
more f>m 9:1
age 40-60%
occurs in 0.5% population
What would you expect to see on exam specific to graves?
Diffuse goitre
ophthalmology - exophthalmos, opthalmoplegia
dermopathy - pretibial myxoedema
uptake scan - increased
What are the possible causes of thyrotoxicosis
Graves Toxic multi nodular goitre - aka Plummer's disease Toxic adenoma Thyrotoxic Phase of thyroiditis - Hashimoto's, subacute lymphocytic Drugs - thyroxine, amiodarone
Management of thyrotoxicosis
medical
- B blocker e.g. propranolol if symptomatic palpitations
- carbimazole inhibits Thyroid peroxidase
radiological
- radio-iodine ( most then become hypothyroid, CI in pregnancy and lactation )
surgical
- thyroidectomy
risk of recurrent laryngeal nerve damage - hoarseness
What would alert you to a thyroid storm?
tempertature agitation, confusion, coma tacky, afib acute abdomen heart failure
What could precipitate a thyroid storm?
recent thyroid surgery or radio-iodine
infection
MI
trauma
What would you see on TFTs of someone with hypothyroid?
low t3 and t4 with elevated TSH
also macrocytic, normochromic anaemia
might have TPO or TSH antibodies
What group usually have hypothyroidism?
females over age 40
symptoms of hypothyroidism
Cold intolerance lethargy low moof mennorhagia weight gain despite reduced appetitie constipation
Signs of hypothyroidism on examination
cold hands bradycardia slow relaxing reflexes dry hair and skin thinning of hair - outer1/3 eyebrows goitre myxoedema - subcutaneous tissue swelling in severe hypothyroidism typically periorbital and on dorsal of hand
Causes of hypothyroidism
primary
- atrophic thyroiditis - commonest in Ireland
- Hashimoto’s thyroidits
- Iodine deficiency - commonest worldwide
- drugs - carbimazole, lithium
- congenital - thyroid genesis
post surgical - thyroidectomy or radio-iodine
secondary to hypopituitarism - rare
