Chempath - Thyroid Flashcards
Normal ranges
TSH: 0.33-4.5 mu/L
Free
T4: 10.2-22.0 pmol/L Free T3: 3.2- 6.5 pmol/L
Which other hormone can stimulate the TSH receptor?
hCG
What effects can amiodarone have on TFTs?
Can be hyper or hypo - high iodine content and direct toxic effects on thyroid
What are the differences between primary atrophic hypoT and hashiomoto’s thyroiditis?
Primary atrophic hypoT: diffuse lymphocytic infiltration & atrophy.
No goiter so small thyroid. No known antibodies detected yet
Hashimotos thyroiditis: Plasma cell infiltration & goitre. Elderly
females. May be initial ‘Hashitoxicosis’. ++ Autoantibody titres (anti TPO/TG)
Rx hyperT
Medical:
Symptom relief - beta blockers, topical steroids for dermopathy, eye drops
Antithyroid meds - carbimazole/propyltiouracil
Two approaches - titrate to normal T3 or block and replace (usually titrate)
SEs: agranulocytosis (rare), rashes (common)
Radio-iodine: good efficacy for primary Rx, risk of permanent hypoT, contraindicated in pregnancy/breast-feeding
Surgical: hemi/total thyroidectomy. Must be euthyroid prior to surgery and will need thyroid replacement therapy after.
Rx hypoT
Thyroid replacement therapy - thyroxine
Papillary Thyroid Ca
> 60% of cases, 30-40y, surgery +/- radioiodine, Thyroxine (to ↓TSH). May see psammoma bodies on histology, these patients have a very good prognosis.
Follicular Thyroid Ca
25%, Middle age, well differentiated but spreads early, Surgery + RI + thyroxine
Medullary Thyroid Ca
5% originates in parafollicular “C” cells – linked to MEN2. Produce calcitonin .
Lymphoma Thyroid Ca
5% MALT origin. Risk factor: chronic Hashimotos (as lots of lymphocytes that proliferate), good prognosis
Anaplastic Thyroid Ca
Rare. Elderly. Poor response to any treatment.
MEN inheritance
AD
MEN1
Pituitary, Pancreatic (e.g. insulinoma), Parathyroid (hyperparathyroidism)
MEN2a
Parathyroid, Phaeochromocytoma, Medullary thyroid
MEN2b
Phaeochromocytoma, Medullary thyroid, Mucocutaneous neuromas (& Marfanoid)
