Chem path 9s - Thyroid

Question 1

What does TSH control the uptake of?

Answer 1

Iodide

Question 2

What blocks TSH?

Answer 2

Perchlorate

Question 3

Normal thyroxine hormone synthesis?

Answer 3

Iodide taken up by thyroid cells
Iodide --> iodine by TPO (Thyroid peroxidase)
Iodine is taken up by thyroglobulin 
Converted to MIT, DIT and T3 and T4
In peripheries T4 --> T3

Question 4

T3 and T4- how does it travel in circulation?

Answer 4

Free and active (0.03%)
Bound to TBG (majority)
Bound to thyroxine-binding pre albumin (TBPA)
Bound to albumin

Question 5

What is Reidel’s thyroiditis associated with?

Answer 5

Hypothyroidism and IgG4 related disease

Question 6

What other hormone can stimulate the same actions as TSH?

Answer 6

bHCG

Question 7

Most hypothyroidism is…

Answer 7

PRIMARY

Question 8

What antibodies are found in Hashimotos?

Answer 8

Anti-TPO and Anti-TG

Question 9

Main Causes of hypothyroidism

Answer 9

Hashimoto’s
Atrophic thyroid (diffuse lymphocytic infiltration and atrophy, no goitre or antibodies)
Post-graves

Question 10

What drugs can cause hypothyroidism classically?

Answer 10

PTU/CBZ + Amiodarone + lithium

Question 11

Which other autoimmune conditions could be associated with Hashimotos?

Answer 11

Pernicious anaema, coeliac, Addisons

Question 12

High TSH + Low T4

Answer 12

Primary hypothyroidism

Question 13

Management of hypothyroidism?

Answer 13

ECG

T4 (titrate to a normal TSH)

Question 14

High TSH Normal T4

Answer 14

Subclinical hypothyroidism or treated hypothyroidism

Question 15

What is sublinical hypothyroidism?

Answer 15

High TSH and normal T4 (body wrongly thinks T4 levels are low)
Predictor for future primary hypothyroidism, esp if anti-TPO is present

Question 16

What other condition is HYPOthyroidism associated with?

Answer 16

Hypercholesterolaemia (this is the only benefit of treating sublinical hypothyroidism)

Question 17

T4 in first trimester

Answer 17

Rise in hCG causes slight rise in free T4

Question 18

t4 in 3rd trimester

Answer 18

hCG levels drop, T4 levels drop too and slight increase in TSH

Question 19

What other thyroid hormone increases during pregnancy?

Answer 19

TBG

Question 20

Initially high TSH then low TSH, low T3 and T4

Answer 20

Sick euthyroidism

Question 21

What is sick euthyroidism?

Answer 21

if you are very sick, the thyroid may shut down to try and reduce the basal metabolic rate to conserve energy (however, there are NO hypothyroid symptoms)

Question 22

3 main cause of hyperthyroidism

Answer 22

1) Graves
2) Toxic multinodular goitre
3) Single toxic adenoma

Question 23

What will the 3 main causes of hyperthyroidism show on technetium scan?

Answer 23

HIgh uptake

Question 24

Post-partum thyroiditis on technetium scan

Answer 24

LOW uptake

Question 25

What is a rare and severe side effect of thionamidse?

Answer 25

Agranulocytosis (sore throat and fever should immediately stop drugs)

Question 26

What are the two ways in which thionamides can be given to treat hyper thyroidism

Answer 26

Block and repalce

Titrate

Question 27

Thionamides MOA

Answer 27

Block TPO i.e. block the conversion of iodide to iodine

Question 28

What drug can be given to hyperthyroid patients before surgery to block the uptake of iodide by the thyroid cells

Answer 28

Potassium perchlorate

Question 29

2 causes of low uptake hyperthyroidism

Answer 29

De Quervain’s

Post partum thyroiditis

Question 30

Important Ix in suspected hyperthyroidism

Answer 30

TFTs
Technetium scan
Anti-thyroid antibodies
Screen for autoimmune antibodies
ECG for concurrent AFib
Bone mineral density

Question 31

Treatment for high uptake hyperthyroidism?

Answer 31

Beta blockers (HR >100) 
CBZ or PTU = to block and replace, or titrate
Consider radio iodine and surgery

Question 32

Treatment for low uptake hyperthyroidism?

Answer 32

Beta blockers

NSAIDs for De Quervain’s thyroiditis (Goitre and painful neck)

Question 33

When is radioidoine inappropriate?

Answer 33

If pt has Grave’s eye disease (exophthalmos), can make it worse

Question 34

Three types of thyroiditis

Answer 34

Silent (painless) thyroiditis
Viral/sub-acute
Post-partum

Question 35

What is the most common type of thyroid cancer?

Answer 35

Papillary carcinoma

Question 36

Pathological feature of papillary carcinoma

Answer 36

Psammoma bodies

Question 37

Treatment of thyroid cancer

Answer 37

Thyroidectomy +/- radioiodine

Thyroxine high dose to suppress TSH and thus reactivation of any remaining cancer tissue

Question 38

What serum marker can be measured to determine recurrence of thyroid cancer post thyroidectomy?

Answer 38

THYROGLOBULIN (TG)

Question 39

Medullary thyroid cancer

• what is it linked to?
• which Ix must you do

Answer 39

MEN 2 (Parathyroid + phaeo)
Calcitonin and CEA levels

Question 40

MTC is a cancer of the … cells of the thyroid gland

Answer 40

The C-cells