1b Hyperthyroidism

Question 1

Where is the thyroxine stored?

Answer 1

In the thyroid follicle which contains thyroglobulin

Question 2

What does T4/3 do?

Answer 2

raise basal metabolic rate

Question 3

Describe the HPT axis

Answer 3

1. Hypothlamus releases TRH
2. This acts on the thyrotrophs in the pituitary to release TSH
3. They act on thyroid to release T3 and T4
4. These hormones then work by negative feedback to inhibit the pituitary and the hypothalamus at each level

Question 4

What level of TSH will you find a patient with primary hypothyroidism, where the thyroid gland has been destroyed by the immune system?

Answer 4

`high TSH

Question 5

How do you control thyroid replacement?

Answer 5

Give thyroxine medication
Increase the dose until the TSH falls to normal

Question 6

Describe the typical appears of the thyroid gland in Graves disease

Answer 6

Smooth, diffuse, symmetrical enlargement of the thyroid gland, pain free when swallowing

Question 7

What are the common symptoms of Grave’s Disease?

Answer 7

Pretibital Myxoedema
Exothphalmos
Weight loss
Tremor
Palpitations
Rapid pulse
Agitation
Smooth Goitre

Question 8

What causes exophthalmos of the eye?

Answer 8

The antibodies bind to the muscles behind the eye and cause it to pop out the socket

Question 9

What causes pretibial myxoedema?

Answer 9

When other antibodies bind to the muscles in he shin and cause hypertrophy of the skin - non pitting swelling

Question 10

Describe the uptake of radioiodine?

Answer 10

Uniform

Question 11

How to confirm graves’

Answer 11

anti anti TSH

Question 12

What is toxic nodular goitre disese?

Answer 12

A benign adenoma which is overactive and making too much thyroxine

Question 13

What is seen in patients with toxic nodular goitre disease?

Answer 13

Unsymmetrical enlargement of the thyroid, with a single hot nodule seen on a rdioiodine scan

Question 14

What is the effect of thyroxine on the sympathetic nervous system? IN ALL HYPERHTYROIDISMS

Answer 14

Thyroxine sensitizes the beta adrenoreeptors to the ambient levels of adrenaline, so there is sympathetic activation

Question 15

What symptoms are seen in hyperthyroidism due to the sympathetic activation?

Answer 15

Tachycadia, palpitations, tremor and lid lag

Question 16

What causes lid lag?

Answer 16

This is inability of the eyelid to close properly due to the excess adrenaline which is holding the eyelid open

Question 17

What are the features of a thyroid storm?

Answer 17

Fever
Accelerated tachycadia
Cardiac Failure
Psychosis
Liver failure

Question 18

What are the three options of treatment for hyperthyroidism/

Answer 18

Drugs
Radiotherapy
Surgery

Question 19

What are the three drugs used to control T4 levels in hyperthyroidism?

Answer 19

Thionamides
Potassium Iodide
Radioiodide

Question 20

What drugs are used for symptomatic control in hyperthyroidism?

Answer 20

NOn-specific Beta blockers to reduce heart rate, tremors

Question 21

How do thionamides work?

Answer 21

They inhibit thyroperoxidase synthesis therefore thyroxine cannot be made

Question 22

What is the name of the most common thionamide?

Answer 22

Carbimazole

Question 23

What is a good non specific beta blocker which is used?

Answer 23

Propranolol

Question 24

What are the unwanted actions of thionamides?

Answer 24

agranulocytosis and rashes

Question 25

What is agranulocytosis?

Answer 25

a reduction in neutrophils - patients asked if they have a sore throat as the susceptibility to adaptive infections is higher

Question 26

what is the role of beta blockers in thyrotoxicosis?

Answer 26

It takes several weeks for ATDs to have clinical effects \9due to the stored thyroxine in the follicle for up to a month), therefore beta blockers work in the interim

Question 27

When is KI givn as a treatment?

Answer 27

prepare hyperthyroid patient for surgery
thyroid storm

Question 28

How does KI work as a treatment for hyperthyroidism?

Answer 28

Inhibition of thyroid hormone synthesis due to the Wolff-Chaikoff effect. - the KI inhibits the iodination of TG and theefore inhibits hydrogen peroxidase production

Question 29

Why is KI given to hyperthyroid surgery patients?

Answer 29

The gland becomes less vascular and undergoes ATROPHY therefore becomes easier to operate on

Question 30

What are the risks of thyroid surgery?

Answer 30

Risk of voice change due to damage to the recurrent laryngeal nerve

Risk of losing parathyroid glands

Question 31

Which patients cannot use radioiodine?

Answer 31

Pregnant women, and people with kids, people around children as they become radioactive

Question 32

Why is pertechnetate used instead of radioiodine?

Answer 32

Cheaper

Question 33

what are the names of the two anti-thyroid drugs?

Answer 33

Carbimazole
Propylthiouracil

Question 34

What is viral thyroditis?

Answer 34

When a virus infects the thyroid gland and overrules thyroxine production and results in hyperthyroidism as all the thyroxine which is stored in the follicles is released

Question 35

How to differentiate between viral thyroditis and Graves?

Answer 35

Viral = painful when swallowing

Question 36

What are the symptoms of viral thyroditis?

Answer 36

Thyroid visibly enlarged on one side
Dysphagia, Pain radiating to the ear

Question 37

What is seen on a radioiodine scan of the thyroid in a patient with viral thyroditis?

Answer 37

Nothing as there is no iodine uptake

Question 38

What is seen when monitoring a patient with viral thyroditis over a three monthperiod?

Answer 38

First hyperthyroidism as all the stored thyroxine is released and TSH drops

Then hypothyroidism as the stored thyroxine is released

After a further month the disease is resolved

Question 39

How is postpartum thyroditis different to viral thyroditis?

Answer 39

No pain and only occurs after pregnancy as the immune system is moduled during pregnancy