Endo - Thyroid Disorders

Question 1

What level of TSH is found in a patient with hypothyroidism + the thyroid gland has been destroyed by immune system?

Answer 1

high TSH

Question 2

What is Graves’ disease?

Answer 2

→ autoimmune
→ antibodies bind to + stimulate TSH receptor
→ cause goitre (smooth) + hyperthyroidism

Question 3

What are signs of Graves’ disease?

Answer 3

→ being warm + sweaty (heat intolerance)
→ tachycardia
→ exophthalmus
→ smooth enlarged goitre
→ increased bowel activity
→ weight loss despite increased appetite
→ oligomenorrhea / amenorrhea
→ pretibial myxedema
→ lid lag + other sympathetic features
→ breathlessness

Question 4

What causes exophthalmus?

Answer 4

antibodies bind to muscles behind the eye causing bulge

Question 5

What’s pretibial myxoedema?

Answer 5

other antibodies causes hypertrophy + swelling + growth of soft tissue at shins

Question 6

What is myxedema?

Answer 6

severely advanced hypothyroidism

Question 7

What does the thyroid gland look like in Graves’ Disease?

Answer 7

→ diffused enlargement + engorgement of smooth goitre

→ diffused goitre of large size after radioiodine uptake + sometimes in pyramidal lobe

Question 8

What are the symptoms of Plummer’s Disease?

Answer 8

→ Toxic nodular goitre
→ NOT autoimmune
→ Benign adenoma that is overactive at making thyroxine.
→ NO pretibial myxoedema
→ NO exophthalmos

Question 9

What does the thyroid gland look like in Plummer’s Disease?

Answer 9

→ only nodule is swollen due to hyperplasia

→ one-sided swelling on goitre, not very smooth, even after radioiodide uptake

Question 10

What are the effects of thyroxine on the SNS?

Answer 10

→ sensitises beta adrenoreceptors to ambient levels of adrenaline + noradrenaline
→ causes apparent sympathetic activation
→ tachycardia, palpitations, tremor in hands, lid lag

Question 11

What is a thyroid storm?

Answer 11

→ untreated hyperthyroidism
→ medical emergency
→ 50% mortality rate

Question 12

What are the symptoms of a thyroid storm?

Answer 12

→ Hyperpyrexia > 41oC
→ accelerated tachycardia / arrhythmia
→ cardiac failure
→ delirium / frank psychosis
→ hepatocellular dysfunction; jaundice

Question 13

What are the drugs used to treat hyperthyroidism?

Answer 13

→ the thionamides (thiourylenes; anti-thyroid drugs)
- propylthiouracil (PTU)
- carbimazole (CBZ)
→ Potassium Iodide
→ Radioiodine
→ β-blockers (for symptoms)

Question 14

What are the drugs used to treat hyperthyroidism?

Answer 14

→ the thionamides (thiourylenes; anti-thyroid drugs)
- propylthiouracil (PTU)
- carbimazole (CBZ)
→ Potassium Iodide
→ Radioiodine
→ β-blockers (for symptoms)

Question 15

How do thioamides treat hyperthyroidism?

Answer 15

→ inhibition of TPO (thyroid perioxidases)
→ stops T3 + T4 synthesis
→ biochemical effect = hours
→ clinical effect = weeks

Question 16

What are the unwanted side effects of thioamides?

Answer 16

→ agranulocytosis (usually reduction in neutrophils) - rare and reversible on withdrawal of drug.
→ rashes (relatively common)

Question 17

How do you follow up on a patient taking thioamides?

Answer 17

→ Usually aim to stop anti-thyroid drug treatment after 18 months
→ Review patient periodically including DTFT (dynamic thyroid function tests) for remission/relapse

Question 18

When is iodide used to treat hyperthyroidism?

Answer 18

→ preparation of hyperthyroid patients for surgery

→ severe thyrotoxic crisis (thyroid storm)

Question 19

How is iodide used to treat hyperthyroidism?

Answer 19

→ inhibits iodination of thyroglobulin
→ inhibits H2O generation + thyroperioxidase
→ inhibition of thyroid hormone synthesis + secretion
→ WOLF-CHAIKOFF effect - presumed auto-regulatory effect
→ symptoms reduce within 1-2 days
→ gland reduces in vascularity + size 10-14 days

Question 20

What are the risks of a thyroidectomy?

Answer 20

→ Risk of voice change
→ Risk of also losing parathyroid glands
→ Scar
→ Anaesthetic

Question 21

What are the names of the two thionamides?

Answer 21

• propylthiouracil (PTU)

- carbimazole (CBZ)

Question 22

How much radioiodine is given to someone?

Answer 22

capsule of approx. 370 MBq (10mCi) of isotope I (131)

Question 23

What are the directions of use of radioiodine?

Answer 23

→ contraindicated in pregnancy

→ need to avoid children + pregnant women for 10 days

Question 24

What is an option of radioiodine only for scans, not treatment?

Answer 24

99-Tc pertechnetate

Question 25

What is Viral (de Quervain’s) thyroiditis?

Answer 25

viral infection of the thyroid

Question 26

What are the symptoms of viral thyroiditis?

Answer 26

→ Painful dysphagia
→ Hyperthyroidism
→ Pyrexia (fever)
→ Thyroid inflammation (enlarged more on one side)

Question 27

How does viral thyroiditis cause hyperthyroiditis?

Answer 27

→ Virus attacks thyroid gland causing pain and tenderness
→ all stored thyroxine is released - hyperthyroidism
→ Thyroid stops making thyroxine and makes viruses instead
→ Thus ZERO iodine uptake

Question 28

Why is iodine given to a patient before a thyroidectomy?

Answer 28

→ gland is overactive, highly vascularised - would bleed a lot if cut into
→ iodine makes the gland normal for ten days (paler, firmer, less likely to bleed and tear as much)\
→ however, only for ten days

Question 29

Why does a viral thyroiditis patient become hypothyroidic after 4 weeks?

Answer 29

→ virus makes the thyroid make thyroid gland make more virus instead of thyroxine
→ all stores of thyroxine deplete in a month so patient becomes hypothyroidic

Question 30

What does the thyroid gland look like in viral thyroiditis radiologically after iodine uptake?

Answer 30

→ there is no iodine uptake

→ so comes up BLANK

Question 31

How is viral thyroiditis treated?

Answer 31

→ after three months of the hypothyroid phase, there should be slow recovery of patient and their thyroid gland
→ giving anti-thyroid or thyroid medication could have unnecessary outcomes