hyperthyroidism

Question 1

what is Grave’s disease?

Answer 1

autoimmune

antibodies bind to and stimulate TSH receptors in thyroid gland

Question 2

what does stimulation of the gland cause?

Answer 2

• smooth goitre
• exophthalmos
• pretibial myxoedema

Question 3

what is plummer’s disease?

Answer 3

not autoimmune but a benign adenoma

Question 4

what are the symptoms of plummer’s?

Answer 4

• toxic nodular goitre
• no pretibial myxoedema
• no exophthalmos
• hot nodule on thyroid uptake scan

Question 5

what are the symptoms of general hyperthyroidism?

Answer 5

• weight loss
• duspnoea
• palpitations
• tachycardia
• sweating
• diarrhoea
• lid lag and other SNS features

Question 6

what causes these SNS features?

Answer 6

• thyroxine sensitises beta-adrenoreceptors to ambient levels of A/NA
• leads to SNS activation

Question 7

describe what happens in Viral (de Quervain’s) Thyroiditis

Answer 7

hyperthyroidism –> hypothyroidism

• virus attacks thyroid gland
• virus lyses the cell so thyroxine spill out into blood
• thyroid not creating thyroxine
• hyperthyroidism becomes hypothyroidism after a month

Question 8

describe the features of this

Answer 8

• painful/tender dysphagia
• hyperthyroidism
• pyrexia
• raised ESR
• zero iodine uptake on uptake scan

Question 9

what is thyroid storm and its features?

Answer 9

• medical emergency
• hyperpyrexia
• accelerated tachycardia/arrhythmia
• cardiac failure
• delirium/frank psychosis
• hepatocellular dysfunction, jaundice

Question 10

what treatment does thyroid storm need?

Answer 10

• surgery
• radioiodine
• drugs

Question 11

what are the different classes of drugs used to treat hyperthyroidism?

Answer 11

• thionamides
• potassium iodide
• radioiodine
  all of these inhibit thyroxine synthesis
• beta blockers
  combats symtpoms

Question 12

name 2 examples of thionamides

Answer 12

Propylthiouracil

Carbimazole

Question 13

what is the clinical use of thionamides?

Answer 13

• daily treatment of hyperthyroid conditions
• treatment prior to surgery
• reduction of symptoms while waiting for radioiodine to act

Question 14

what is the MoA of Thionamides?

Answer 14

• inhibits TPO and peroxidase transaminase
• supress antibody production in Graves
• reduce T4 –> T3 in peripheral tissues

Question 15

what are the unwanted effects of thionamides?

Answer 15

• agranulocytosis (reduction of granular leukocytes)

- rashes

Question 16

what are the pharmacokinetics of these?

Answer 16

• orally active
• carbimazole is pro-drug
• plasma half life is 6-15 hours
• crosses placenta
• metabolised in liver, secreted in urine

Question 17

when is potassium iodide used?

Answer 17

• preparation of hyperthyroid patients for surgery

- in severe thyroid storm crisis patients

Question 18

what is the MoA of potassium iodide?

Answer 18

• inhibits iodination of TG
• inhibits hydrogen peroxide
• wolf-chaikoff effect

Question 19

what is the unwanted reaction with potassium iodide?

Answer 19

allergic reactions

Question 20

what does HIGH DOSE radioiodine treat?

Answer 20

• hyperthyroidism

- thyroid cancers

Question 21

what is the MoA of this?

Answer 21

radioiodine accumulates in thyroid and emits beta particles

this destroy follicular cells

Question 22

what are the pharmacokinetics of iodine treatment?

Answer 22

• single dose orally
• half life of 8 days
• negligible after 2 months