Chempath 9: Thyroid Flashcards
Which auto-antibodies are seen in Hashimoto’s thyroiditis ?
anti-TPO
also anti-TG
Which auto-antibodies are seen in Grave’s disease?
anti-TSH receptor (activates Thyroid production)
what is the most common type of thyroid cancer?
Pappilary thyroid cancer
In which cancer are Psammoma bodies seen on histology ?
Papillary thyroid
also ovarian serous cyst adenoma
which thyroid cancer is associated with MEN2 ?
Medullary thyroid cancer
Which thyroid cancer releases calcitonin ?
Medullary thyroid cancer
List the 3 cancers seen in MEN1
Pituitary
Parathyroid
Pancreatic (Insulinoma)
3 Ps
List the 3 cancers seen in MEN2a
Phaeochromocytoma
Parathyroid
Medullary thyroid
2 Ps 1 M
List the 3 cancers seen in MEN2b
Phaeochromocytoma
Medullary thyroid
Mucocutaneous neuromas
1 P 2 Ms
What is the mode of inheritance for MEN ?
Autosomal dominant
List 2 causes of hyperthyroidism with high iodine uptake ?
Grave’s disease
Multinodular goitre
List 2 causes of hyperthyroidism with low iodine uptake ?
De Quervains thyroiditis
Post partum thyroiditis
List causes of hypothyroidism ?
Hashimoto's thyroiditis Atrophic hypothyroidism Iodine deficiency post thyroidectomy/Post radioactive iodine Drugs- Lithium, Amiodarone
Which drug can be used to treat hyperthyroidism without inducing permanent hypothyroidism?
carbimazole
how is thyroxine made
TSH controls the uptake of iodide to the thyroid (blocked by perchlorate)
Iodide goes through the membrane via Na+/l+/ATPase
Iodide converted to iodine by thyroid peroxidase
Iodine taken up by thyroglobulin and converted into thyroxine (T4)
Converted to T3 in the periphery
how is most thyroxine transported around the body
bound to thyroxine binding globulin (TBG)
list causes of hypothyroidism
Hashimotos thyroiditis atrophic thyroid post-graves disease drugs (amiodarone, lithium) thyroid agenesis/dysgenesis
why would you do an ECG in someone with hypothyroidism
if they have an underlying cardiovascular disease, their myocardial contractility will increase - risk of ischaemia
how is hypothyroidism treated
T4 (levothyroxine)
features of subclinical hypothyroidism
T4 is normal and TSH high
associated with hypercholesterolaemia
describe thyroid function in pregnancy
hCG has a similar structure to TSH
too much hCG - thyroid gland makes too much thyroxine
rise in hCG in first trimester makes free T4 levels increase slightly
TBG levels increase dramatically in pregnancy (under control of oestrogen)
features of neonatal hypothyroidism
diagnosed via Guthrie test
48-72 hours
may be very high if you detect maternal TSH
features of sick euthyroid
alteratio in pituitary axis in non-thyroidal illness
low T4 and T3
normal/high TSH
in any severe illness
causes of hyperthyroidism
graves (40-60%)
toxic multinodiular goitre (30-50%)
single toxic adenoma (5%)
use a technetium scan to see which parts of the thyroid are making excessive thyroid hormone
management for hyperthyroidism
beta blocker if pulse >100 ECG bone mineral density radioactive iodine thionamides - carbimazole, propylthiouracil, prevent the conversion of iodine to iodine by thyroid peroxidase
what is a rare side effects of thionamides
agranulocytosis
features of thyroiditis
can be asymptomatic
some form of pain in the neck
initial inflammation of the thyroid releasing excessive amounts of thyroid hormone
long-term treatment = thyroid replacement therapy
list the 2 most common types of thyroid carcinoma
papillary thyroid cancer
follicular thyroid cancer
treatment for thyroid carcinoma
total thyroidectomy
radioiodine after surgery to remove any remaining thyroid cells
after this, given high dose thyroxine to lower TSH levels so TSH doesn’t stimulate any remaining cancer cells
TG measured in the serum as a tumour marker
features of medullary carcinoma of the thyroid gland
rare
can be sporadic, familial, or part of MEN 2
cancer of the C cells of the thyroid gland (these make calcitonin)
tumour makers:
- calcitonin
- CEA (carcionoembryonic antigen)
