Thyroid Flashcards
T4 is converted to T3 to be activated - true or false?
TRUE
Oestrogens combined with levothyroxine can cause increase in the amount of iodine thyroglobulin binding? True or false?
TRUE
This is how the thyroid is stored
Hypothyroidism is…?
When there are low amounts of the thyroid hormone.
LOW TSH and LOW T3
Levothyroxine is a synthetic form of T3? True or false?
TRUE
When should monitoring with levothyroxine be done?
In the first 4-6 weeks
Too high levo = low TSH
Too low levo = Hight TSH
Levothyroxine doses should be tittered up slowly true of false?
true
Prevents thyroid storm or severe side effects of too much thyroid hormone I.e. sweating/increased HR
Once levothyroxine dose has been established, how often should levels be monitored?
Levels should be monitored annually once stable dose is found
What things can affect levothyroxine absorption?
- Taking levothyroxine with food
- Enzyme inducers will increase metabolism
- Taking with other medications = May form salts in the gut I.e. calcium/ferrous sulfate
- Oestrogens can cause increase in TBG levels (contraceptives/HRT)
Counselling for patient taking levo?
Take on an empty stomach 30-60 minutes before food
Liothyronine is a synthetic version of T3 or T4?
T3.
Is therefore more potent than levo
What is the conversion between liothyronine and levo?
20 mcg = 100 mcg
Lio = levo
Caution in what types of patients with liothyronine ?
Cardiovascular patients
Elderly
Licensed beta-blockers for beta-adrenergic symptoms associated with hyperthyroidism?
Nadolol
Metoprolol
Propranolol
Examples of thionamides?
Carbimazole
Propylthiouracil
What can carbimazole be used for?
Treatment of:
- Long term hyperthyroidism
- Hyperthyroidism in pregnancy
- Graves’ disease remission and treatment
- Non toxic goitre (multi nodular)
Thionamides MOA?
Impair the formation of iodine TBG
And propylthiouracil stops conversion of T4 to T3
Is there a small chance of birth defects with thionamides?
Yes
Alternative treatment to hyperthyroidism in pregnancy
Radioactive iodine treatment for at least 6 months before conception
Side effects of thionamides/carbimazole
Agranulocytosis and neutropenia
When are the blood side effects of carbimazole likely to show?
Firs three months of use
Need for FBC and monitoring during this time
History of blood disorders mean that carbimazole is contra-indicated. True/false
True
Alongside blood disorders what should be recognised as potential side effect with carbizmazole?
Liver disease
Patients should be able to spot jaundice and so on
IV hydrocortisone and oral prednisolone can help to do what?
Bring down levels of T3
