Thyroid Disorders Flashcards
What 2 hormones does the thyroid gland secrete?
Thyroxine T4
Active T3
What happens to TSH release in hyper & hypothyroidism?
Remember them as opposites
Hypothyroidism = HIGH TSH
Hyperthyroidism = LOW TSH
What 2 substances are always tested in a thyroid function test (TFT)?
TSH & T4
How long does it take for TSH levels to adjust after therapy?
Up to 8 weeks
In hyperthyroidism, is T4 or T3 higher?
T3
Why aren’t TSH levels always high in hypothyroidism?
Because TSH levels take time to adjust
What substance does synthesising thyroxine require?
Iodine
What is thyroiditis?
It is an inflammation of the thyroid gland due to e.g. a virus, drug-induced, autoimmune or post-partum
What are the symptoms of viral thyroiditis?
Flu like symptoms + hyperthyroidism, then hypothyroidism
What treatment is used for viral thyroiditis?
NSAIDs + short course of steroids + b blockers
What drugs interact with the thyroid gland?
Lithium - hypo
Amiodarone - hyper or hypo
Iodide - hyper
Glucocorticoids/dopamine - hyper
Aspirin
Anticonvulsants
Why are the symptoms of hypothyroidism?
Remember everything as SLOW
Constipation
Weight gain
Goitre
Coldness
Bradycardia
Muscle stiffness
Lethargy
What can cause hypothyroidism?
Hashimoto’s disease
Drug induced
Radioiodide/surgical treatment of hyperthyroidism
What is the treatment of hypothyroidism?
Levothyroxine dose ranging from 25-200mcg daily
When are TFT’s assessed in hypothyroidism?
After 6 weeks of treatment to allow TSH to stabilise, then every 6-12months
What drug is used in severe hypothyroidism (include dose)?
Liothyronine sodium 10-20mcg oral or IV
What are the symptoms of hyperthyroidism?
Remember everything as FAST
Diarrhoea
Increased appetite
Weight loss
Goitre
Tachycardia/palpitations
Irritability
Why are b-blockers given in hyperthyroidism?
To control the symptoms of tremor/palpitations/tachycardia
Why should you be careful when giving b-blockers to a diabetic patient?
Because b-blockers can mask hypoglycaemic symptoms.
What causes hyperthyroidism?
Graves Disease - antibodies looking like TSH bind to thyroid gland and secrete more T3/T4
What is the mode of action of carbimazole?
It prevents the coupling of tyrosine and iodine so reduced T3 and T4 levels
How long is carbimazole used for in hyperthyroidism?
12-18 months
What side effect should patients taking carbimazole report immediately?
Sore throat/fever/infections as carbimazole can cause agranulocytosis
Why is levothyroxine & carbimazole sometimes given together?
To balance hypo & hyperthyroidism states (avoiding under/overtreatment)
What risk can increase if radioactive iodine is used as treatment for hyperthyroidism?
Hypothyroidism
What are examples of some b-blockers used in hyperthyroidism?
Nadolol
Propranolol
Metoprolol
What MUST be present before surgery in hyperthyroidism?
Normal thyroid function to reduce palpitations/tachycardia during surgery
B-blockers are given to prevent this
Why is unactive T4 sometimes given before surgery?
To reduce the bleeding risk associated with b-blockers
What should replace anti-thyroid drugs 10-14 days before a thyroidectomy?
Potassium iodide to inhibit thyroid release
What complications can arise from a thyroidectomy?
Hypocalcaemia
Hypothyroidism
Hypoparathyroidism
How often should TFT’s be measured after a thyroidectomy?
At 2 and 6 months, then annually.
How often should TFTs of anti-thyroid drugs be measured?
After 8 weeks of treatment, then every 3 months for 1 year, then annually
What can cause a thyroid crisis?
Infection
Stress
Unprepared patient before surgery
What is the management of a thyroid crisis?
High dose carbimazole
Propranolol
Dexamethasone
Iodine T4
