Hyperthyroidism

Question 1

What is the causes of Grave’s disease?

Answer 1

Autoimmune - antibodies bind to and stimulate TSH receptors in the thyroid

Question 2

What happens to the body in Grave’s disease?

Answer 2

Stimulation of gland causes growth and forms a smooth goitre
Also causes lid lag
Other antibodies bind to muscles behind the eyes and cause exophthalmos
Other antibodies cause pretibial myxoedema
Non pitting oedema

Question 3

What is the cause of Plummer’s disease?

Answer 3

Not autoimmune - a benign adenoma

Question 4

What is different in Plummer’s disease to Graves?

Answer 4

Toxic nodular goitre which no pretibial myxoedema and no exophthalmos and is also called a ‘hot nodule’ on a thyroid uptake scan

Question 5

What are signs and symptoms of general hyperthyroidism?

Answer 5

Everything SPEEDS UP
Weight loss
Dyspnoea
Palpatations, tachycardia
Sweating and heat intolerance
Diarrhoea
Lid lag and other SNS features

Question 6

How does hyperthyroidism lead to apparent SNS activation?

Answer 6

Thyroxine sensitises beta-adrenoceptors to ambient levels of adrenaline and noradrenaline (not more adrenaline, just more sensitive receptors) which leads to the SNS activation

Question 7

What is Viral (de Quervains) Thyroiditis?

Answer 7

Painful/tender dysphagia with hyperthyroidism and prexia - fever and a raised erythrocyte sedimentation rate

Question 8

How can hyperthyroidism become hypothyroidism after a month in Viral (de Quervains) Thyroiditis?

Answer 8

Virus attacks thyroid gland causing pain and tenderness, then the virus lyses the cell and thyroxine spills out into the blood (hypertension) and then the thyroid is not creating thyroxine hyper -> hypothyroidism

Question 9

What is shown on an uptake scan in Viral (de Quervains) Thyroiditis?

Answer 9

ZERO iodine uptake

Question 10

What is a thyroid storm? What are the signs and symptoms?

Answer 10

Medical emergency!!
Hyperpyrexia – high fever (>41).
Accelerated tachycardia/arrhythmia.
Cardiac failure.
Delirium/frank psychosis.
Hepatocellular dysfunction, jaundice

Question 11

What is the treatment for a thyroid storm?

Answer 11

Surgery (thyroidectomy)
Radioiodine
Drugs

Question 12

What are the three drugs that inhibit thyroxine synthesis?

Answer 12

Thionamides
Potassium iodide
Radioiodine

Question 13

What are 2 examples of thionamides? What are they?

Answer 13

Propylthiouracil
Carbimazole
which are anti-thyroid drugs

Question 14

What is the clinical use of thionamides?

Answer 14

Daily treatment of hyperthyroid conditions eg grave’s
Treatment prior to surgery
Reduction of symptoms while waiting for radioactive iodine to act

Question 15

What is the mechanism of action of thionamides?

Answer 15

Inhibits TPO and peroxidase transaminase
Suppress antibody production in graves
Reduce T4 -> T3 in peripheral tissues

Question 16

What is the difference between the biochemical and clinical effects of thionamides?

Answer 16

There is a biochemical effect in hours but no clinical effect until a week or so has passed so there is a large store of normal thyroxine in the thyroid gland which is released for a while

Question 17

What other drug is usually paired with thionamides in a treatment plan for hyperthyroidism?

Answer 17

Propanolol which is a beta blocker to rapidly reduce treamours and tachycardia

Question 18

What are unwanted actions of thionamides?

Answer 18

Agranulocytosis - reduction or absence of granular leukocytes
Rashes

Question 19

What is the pharmacokinetics of thionamides? (administration? half life? metabolize rate?)

Answer 19

Orally active prodrug that has a plasma half life of 6-15 hours and crosses the placenta so is secreted in breat milk and metabolised in liver and secreted in urine

Question 20

What is the follow up for thionamides?

Answer 20

Stop anti thyroid treatment after 18 months and review patient frequently

Question 21

When is iodine treatment of KI used in hyperthyroidism?

Answer 21

Preparing the hyperthyroid patient for surgery

In severe thyroid storm crisis

Question 22

What is the mechanism of action of iodine treatment for hyperthyroidism?

Answer 22

Inhibit iodination of TG
Inhibit hydrogen peroxide generation
WOLF CHAIKOFF EFFECT

Question 23

What are unwanted reactions of KI treatment for hyperthyroidism?

Answer 23

Allergic reactions

Question 24

What are the pharmacokinetics of KI treatment for hyperthyroidism? (administration? When is maximum effect?)

Answer 24

Orally active - lugol’s solution with maximum effect after 10 days of continuous administration