Thyroid Disease

Question 1

Graves Disease

Answer 1

Antibodies against TSH receptor

2.5% of women and .25% of men

Increased with family history, recent iodine exposure and postpartum

Diagnosis = Thyroid scan or TSH receptor antibodies

Question 2

Management of Graves disease

Answer 2

Control symptoms = Beta blockers

Control hyperthyroidism =

• Thionamides - Carbimazole or propylthiouracil
• Iodine 131
• Surgery

Question 3

PTU vs Carbimazole

Answer 3

PTU =

• Shorter half life
• Blocks conversion from T4 to T3
• Safer in pregnancy
• Associated with fulminant inflammatory hepatitis

Carbimazole =

• Daily dose
• No effect on deiodinase

S/Es: Rash, Raised LFTs, neutropenia, pANCA vasculitis

Question 4

Approach to thionamide therapy

Answer 4

Titrate to effect
12-18 months of treatment

50% of long term remission
Most relapses in six months

Question 5

Graves ophthalmopathy

Answer 5

Can be independent of thyrotoxicosis
Can be asymmetrical

SMOKING +++
Iodine therapy

Management = steroids and surgical debulking

Question 6

Periodic paralysis associated with graves disease?

Answer 6

Transient severe hyperkalaemia following high carbohydrate meal or severe exercise

Asian people

Only during thyrotoxic phase
Control by controlling thyrotoxicosis

Question 7

Toxic MNG

Answer 7

Increased with poor iodine intake

Usual presentation of thyrotoxicosis
Can be isolated T3 increase

Treat with Iodine 131

Monitor for malignancy

Question 8

Thyroiditis

Answer 8

Thryotoxicosis without TSHR and with poor uptake on thyroid scan

Causes:

• De Quervians
• Post pregnancy
• Hashimotos
• Amiodarone

Treat wit NSAIDS and pred for pain and beta blockers for symptoms

Question 9

Amiodarone induced thyroid disease

Answer 9

Hypothyroidism:

• Due to interference of T4 synthesis
• Withdraw amiodarone and commence thyroxine

Hyperthyroidism:
- Type 1 = iodine load
- Type 2 = thyroiditis = Free T4&raquo_space;»T3
Treatment = stop amiodarone and commence steroids and PTU/CBZ

Question 10

Lithium and thyroid?

Answer 10

Hypothyroidism due to inhibition if T4 production and secretion

Thyroiditis

Question 11

Immunotherapy and the thyroid?

Answer 11

Anti CTLA-4 and PD-1 inhibitors –> thyroiditis and central hypothyroidism

Anti-CD52 - alemtuzumab = graves disease and thyroiditis

Interferon Alpha –> hypothyroidism

TKIs –> hypothyroidism

RXR agonist –> decreased TSH –> hypothyroidism

Question 12

When to treat subclinical hypothyroidism

Answer 12

Definitely:

• TSH >10
• Symptoms of hypothyroidism
• Preconception or early pregnancy

Consider:

• HF
• Antibody positive
• High cholesterol

Question 13

When to treat subclinical hyperthyroidism

Answer 13

TSH <0.1
Symptoms of thyroxicosis
Co-existing AF or OP

Question 14

Types of thyroid cancer

Answer 14

Follicular:

• Follicular carcinoma
• Papillary carcinoma
• Poorly differentiated carcinoma

Medullary cancer

• MEN 2 and MTC - RET mutations
• LETHAL

Question 15

Genetic drivers of papillary carcinoma

Answer 15

BRAF V600E = 60%
RTK fusions = 15%
RAS = 13%

Question 16

Assessing nodules ? cancer

Answer 16

Should be >1cm

? TSH normal - if normal more likely cancer
FNA - if malignant = surgery
FNA = normal = monitor for growth

Question 17

Treatment of follicular derived thyroid cancers

Answer 17

Thyroidectomy and LN dissection

Papillary >1cm or follicular = post op iodine 131 ablation AND if high risk TSH suppression
Allows follow up with iodine 131 scan and thyroglobulin antibodies
Survival benefit only if local invasion or mets at Dx

Papillary <1cm and no mets = nil abalation or suppression

Question 18

Systemic treatments for follicular derived thyroid cancers

Answer 18

Use to increase differentiation prior to further Iodine 131 therapy

Multitargeted TKIs:

• Sorafenib
• Vemurafenib - Targets BRAK 600E mutation

Question 19

Treatment of medullary thyroid carcinoma

Answer 19

Thyroidectomy
RET oncogene sequencing

Monitor with calcitonin levels

Question 20

Thyroid and pregnancy

Answer 20

BHcG can stimulate TSH receptor –> low TSH
Associated with hyperemesis of pregnancy

Must increase dose of T4 in pregnancy x 1.3 in 1st 20 weeks if possible

Treat subclinical hypothyroidism

Question 21

Diagnosing factitious hyperthyroidism?

Answer 21

Psych history/body image/treated hypthyroidism
No goitre/ nodules/ exophthalmos
High T4/T3 ratio (if thyroxine ingestion)
If acute TSH incompletely suppressed despite very high fT4
No aTPO* or aTSHR antibodies

Low/ suppressed thyroglobulin