Thyroid Flashcards
What is thyroxine also known as?
T4
Do you measure free or bound thyroxine?
Free
What is more common primary or secondary hyperthyroidism?
Primary
What are fT4 and TSH in primary hyperthyroidism?
High fT4
Low TSH
What are fT4 and TSH in secondary hyperthyroidism?
High fT4
High TSH
Name 3 causes of primary hyperthyroidism. What is the commonest’s cause?
Grave’s disease - commonest
Toxic multinodular goitre
Thyroiditis
Hot nodule - solitary toxic adenoma
What autoantibody is seen in Grave’s disease?
TRAbs thyroid receptor antibodies
What features in Grave’s disease are not seen in other causes of hyperthyroidism?
Thyroid eye disease
Thyroid acropachy
Pretibial myxedema
What features of a goitre help differentiate the cause of hyperthyroidism?
Grave’s: large smooth non-tender goitre
Toxic multinodular goitre: lumpy tender
Thyroiditis: smooth tender
Name 3 causes of thyroiditis
Post viral infection
Post-partum
Amiodarone
What is the management of grave’s thyroid eye disease?
Steroids
(IV/PO depending on severity)
(sight loss risk)
Name 1 cause of secondary hyperthyroidism
TSH secreting pituitary tumour, ectopic thyroid tissue
What type of imaging is used first for investigating hyperthyroidism?
US
Is a nuclear medicine technetium uptake test done for all with hyperthyroidism?
If antibody negative or diagnostic uncertainty
What is seen on Graves’ disease and toxic multinodular goitre in a nuclear medicine technetium uptake test?
Grave’s uniform uptake
TMNG patchy uptake
What is the first line management of Graves’ disease?
Carbimazole
(titrate dentist every 6 week until euthyroid)
(cures 50% patients)
What is the management of Graves’ disease if pregnant or intolerant of carbimazole?
PTU propylthiouracil
What is the common side effect of carbimazole? How is it managed?
Itch/rash – antihistamine
What is the rare but important side-effect of carbimazole?
Agranulocytosis - sore throat, dry cough, mouth ulcers, bruising, fever
(monitor FBC, neutrophils, reversible if stop)
What is the use of beta-blockers in hyperthyroidism?
For adrenergic type symptoms: tremor sweat anxiety palpitations
What is a hot and cold nodule?
Hot - making hormone
Cold – doesn’t make anything (suspicious cancer)
Deficiency of what can cause a goitre?
Iodine
Following radioactive iodine treatment, how long should patients isolate for?
3 weeks
What nerve may be injured in thyroid surgery?
Recurrent laryngeal nerve – hoarse voice
Untreated hyperthyroidism can lead to what complication?
Thyroid storm
Thyroid storm
- High or low temp
- Dehydration or fluid overload
- Low or high HR
- Low or high BP
High temp Dehydration High HR Low BP Also confusion/anxiety/delirium, N+V, arrhythmias
What is the management of a thyroid storm?
Fluids + propranolol + PTU + hydrocortisone + paracetamol + phenobarbital + furosemide/ACEI
What are fT4 and TSH in primary hypothyroidism?
low fT4
TSH high
What are fT4 and TSH in secondary hypothyroidism?
low fT4
low TSH
Name 3 causes of primary hypothyroidism
Hashimoto's disease Idiopathic Thyroiditis Iodine deficiency History of thyroid irradiation/surgery
Name 2 causes of secondary hypothyroidism
Pituitary neoplasm
Hypothalamic neoplasm
Congenital
Sheehan syndrome (pituitary necrosis/apoplexy)
Does lithium cause hypo or hyperthyroidism?
Either
What autoantibody is associated with Hashimoto’s disease?
TPO
What is the first line management of hypothyroidism
Levothyroxine T4
What is a complication of decompensated hypothyroidism?
Myxedema coma
What would be seen on blood results in subclinical hypothyroidism?
Normal fT4, high TSH
What is the management of subclinical hypothyroidism?
Repeat TFTs in a few months
What is the management of myxoedema coma?
Supportive + IV hydrocortisone + IV levothyroxine T4
What is the 5% rule with thyroid cancer?
5% of women have thyroid lumps, 5% of them are malignant
Most thyroid nodules are benign hyperplastic lesions – true or false
True
Is a thyroid cancer lump tethered to surrounding structures or mobile?
Tethered
Cytology determines the staging of thyroid cancer – true or false
False cytology does grading not staging
Cytology can’t see if invaded the basement membrane
(Graded U2-U5)
What is the commonest type of thyroid cancer? What is the second commonest type of thyroid cancer?
Commonest papillary
Next follicular
TFTs are usually normal in thyroid cancer – T or F
True
When investigating thyroid cancer should you check for thyroid autoantibodies?
Yes for exclusion
What type of biopsy is done for thyroid cancer?
FNA for cytology
Cervical lymphadenopathy + thyroid lump = until proven otherwise
Papillary thyroid cancer
If you find cervical lymphadenopathy on the examination, what should he do next on examination?
Check axilla/groin LN
lymphoma
Are a isotope scan and a technetium uptake scan the same thing?
Yes
What is a hot nodule on an isotope scan diagnostic off?
Solitary toxic adenoma
How old is papillary thyroid cancer and most commonly metastasise?
Lymphatic spread
Is papillary thyroid cancer associated with younger or elderly patients? More male or female?
Young
M = F
Papillary thyroid cancer has an excellent prognosis – true or false
True
What is TSH levels in papillary or follicular thyroid cancer?
Normal or slightly elevated
Does follicular thyroid cancer metastasise early or late? Where does it spread to?
Early to bone/lung
What type of thyroid cancer is associated with CEA?
Medullary
What type of thyroid cancer is associated with MEN?
Medullary
What is used as a tumour marker for monitoring thyroid cancer post surgery?
Thyroglobulin
What is the presentation of MEN1?
3 Ps
Parathyroid, phaeochromocytoma, pancreas (insulinoma, gastrinoma, PUD Zollinger Ellison syndrome)
What gene is mutated in MEN1?
MEN 1 gene
What gene is mutated in MEN2?
RET gene
What is the Mx of low risk thyroid cancer (under 50yr, under 4cm)?
Lobectomy (most function ok after few months with half thyroid)
What is the Mx of low risk thyroid cancer (over 50yr, over 4cm)?
Total thyroidectomy
