Hyperthyroidism Tutorial

Question 1

30F - experiencing palpitations
fT4 30 pmol/L (9 - 23)
fT3 11 pmol/L (3.1 – 6.8)
TSH <0.01 mU/L (0.3 – 4.2)

What is the possible diagnosis / cause?

Answer 1

Primary hyperthyroidism:
Graves’ Disease - autoimmune activation
Plummer’s Disease - benign tumour (toxic nodular goitre)
Drug induced hyperthyroidism
Inflammation of the thyroid - viral infections or post-partum thyroiditis

Question 2

What questions could be asked to the patient to narrow down the differentials?

Answer 2

Do you have any autoimmune conditions or any family history of autoimmune conditions?
Any other symptoms?
Have you had a fever?
Have you noticed any weightloss (despite increased appetite)?
Have you had difficulty swallowing?
Have you experienced any diarrhoea?
Have you experienced anxiety / insomnia?
Are your periods irregular / stopped? (oligo/ameno-rrhoea)
Are you on any other medications? Or have you taken any over-the-counter medications/supplements?
Have you experienced any sweating?
Have you experienced swelling of your shins?
Have you noticed bulging of your eyes?
Have you had a recent pregnancy?

Question 3

Further patients history?
18 month history of palpitations, weight loss and sweating. Snappy at work. 2 aunts with neck surgery, her own swollen
HR = 112, BP = 106 / 70 mmHg, mass in the centre of her neck - soft, extended symmetrically and not tender to touch, moves with swallowing, bilateral exophthalmos (prominent eyes)

What is the likely diagnosis based on the history and examination?

Answer 3

Most likely Graves’ due to exophthalmos (Abs binding to the eyes causing inflammation behind the eye) and symmetrical mass in the neck
For Plummer’s the goitre is unlikely to be symmetrical and they do not experience exophthalmos

Question 4

What investigation will confirm the cause of her hyperthyroidism?

Answer 4

Blood test: look for anti-TSH receptor antibodies

Radioactive iodine scan - technician scan: all the iodine is taken up by the thyroid gland (whole gland shows up black)

Question 5

What treatment should she receive?

Answer 5

Beta blockers: to make them feel better
Potassium iodide: reduces thyroid hormone synthesis (blocks uptake of iodine by the thyroid gland)
Radioactive iodine: shouldn’t fall pregnant for the next 6 months and avoid contact with others for 2-3 weeks due to residual radioactivity
Thionamides: PTU / CBZ (anti-thyroid drugs) slow the uptake / activation of iodine by blocking an enzyme

18 month follow up - condition may be gone or offer surgery (thyroidectomy)