Thyroid disease Flashcards

1
Q

What do the thyroid hormones do

A

Increase metabolism of CHO, protein and fat

Increase O2 consumption

Synergistic with actions of catecholamines

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2
Q

What are the two types of goitres

A

Diffuse (spread over the neck)

Nodular (discrete area that is clearly different from surrounding thyroid gland

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3
Q

What is a goitre

A

Enlarged thyroid gland (non specific term for any enlargement of the thyroid gland)

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4
Q

When would diffuse goitres be formed

A

When there is over-stimulation of the thyroid gland by either TSH or TSI (Graves’ disease)

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5
Q

Different causes of hypothyroidism

A
  • PRimary ofailure of thyroid gland (Hashimoto’s thyroiditis)
  • Secondary to hypothalamic or anterior pituitary failure
  • Lack of dietary iodine
  • Drug induced
  • Thyroid hormone resistance
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6
Q

What is Hashimoto’s thyroiditis and what are the plasma concentrations of hormones with this disease?

IS there a goitre present

A

Autoimmune disease of the thyroid

Low T3 and T4
High TSH

Goitre present

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7
Q

What are the plasma concentrations of hormones like in hypothyroidism caused. by hypothalamic or anterior pituitary failure?

IS there a goitre present

A

Low T3 and T4
Low TSH

No goitre

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8
Q

What are the plasma concentrations of hormones like in hypothyroidism caused by lack of dietary iodine

IS there a goitre present

A

Low T3 and T4
High TSH

Goitre present

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9
Q

Symptoms of hypothyroidism

A
Weight gain
Dry skin
Hoarse voice, slow speech 
Cold intolerance
Constipation
Lowered HR/BP
Depression, confusion, poor memory 

Some may get myxoedema- puffy appearance in face, hands and feet

Reduction in BMR and overall metabolic activity

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10
Q

How is BMR and metabolic activity like in hypothyroidism

A

Reduction in both

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11
Q

What is facial myxoedema

A

round, moon like
Puffy, pale, oedematous eye-lids
Thickened skin and dry

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12
Q

How are new-borns tested for cretinism

A

By testing for TSH and T4

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13
Q

How are primary and secondary hypothyroidism tested

A

Thyroid function test

Primary: low T3 and T4, high TSH

Secondary: Low T3 and T4, low TSH

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14
Q

If you suspect Hashimoyo’s what tests would you do

A

Test for thyroid antibodies

TPO, anti-thyroglobulin antibodies

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15
Q

What is the management of hypothyroidism

A

T4 (treatment of choice)

T3

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16
Q

How is T4 taken and what are the cautions

How to overcome these complications

A

Orally, once a day

  • May worsen or uncover angina
  • -> If angina, beta blocker is prescribed. Baseline ECG given with initial dosage
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17
Q

Why is T3 not routinely given for hypothyroidism? When is it used

A

Has a rapid onset and this can induce heart failure

Used in severe hypothyroid states when rapid response is desired (i.v.)

18
Q

What are the causes of hyperthyroidism

A
  • Abnormal levels of thyroid stimulating immunoglobulins (Graves’ disease)
  • Secondary to excess hypothalamic or anterior pituitary secretion
  • Hyper-secreting thyroid tumour
  • Latrogenic causes
19
Q

What are the plasma conc of hormones in hyperthyroidism caused by Graves’ disease and is. goitre present

A

High T3 and T4
Low TSH

Goitre present

20
Q

What are the plasma conc of hormones in hyperthyroidism caused by secondary to excess hypothalamic or anterior pituitary secretion

A

High T3 and T4
High TSH

Goitre present

21
Q

What are the plasma conc of hormones in hyperthyroidism caused by hyper-secreting thyroid tumour

A

High T3 and T4
Low TSH

Goitre present

22
Q

What does TSI (thyroid stimulating immunoglobulins do )

A

Activate the thyroid gland (by binding to TSH receptors on thyroid gland) to produce and release thyroid hormones

23
Q

What is the most common cause of hyperthyroidism

A

Graves’ disease

24
Q

Classic signs and symptoms of Graves’ disease

A
Weight loss
Sweating 
Heat intolerance
Palpitations
Tremor
Nervousness
Goitre
Exophthalmos (bulging eyes)
25
symptoms of hyperthyroidism
``` Weight loss Sweating Heat intolerance Diarrhoea Palpitations Tremor Anxiety, emotional, irritable Restlessness ```
26
What is the increased cellular/tissue metabolism due to in hyperthyroidism
excessive thyroid hormone action
27
What is also enhanced in hyperthyroidism
Beta adrenoceptor responses
28
How to diagnose hyperthyroidism
primary - high T3 and T4, low TSH Secondary- high T3 and T4, high TSH
29
If you suspect Graves' disease, what tests do you do
Test for thyroid-stimulating antibodies
30
If you suspect thyroid tumours, what tests do you do
Thyroid uptake test using radioactive Iodine
31
what is the goal of treatment for hyperthyroidism
Euthyroid state and symptomatic relied from increased sympathetic activity
32
Management of hyperthyroidism
Anti-thyroid drugs Radioiodine Surgery
33
What are anti-thyroid drugs
Thionamides (carbimazole and propylthyiouracil(PTU))
34
What is the mode of action of anti-thyroid drugs
Decrease production of thyroid hormones by inhibiting iodination and coupling processes via TPO -PTU also block T4 to T3 deionidation
35
HOw long do anti-thyroid drugs take to work
Several weeks because of colloid stores
36
What is the drug of choice for hyperthyroidism and what are the complications
Carbimazole but -rashes and pruritis common -Rare complication: neutropenia and agranulocytosis (bone marrow suppression) which are reversible
37
What drugs can be used to manage hyperthyroidism
Thionamides (anti-thyroid drugs) Non-selective beta blockers
38
What is the action of non-selective beta blockers for managing hyperthyroidism and what they do
Reduce actions of catecholamines -rapid symptomatic relief od tremor, palpitations, and anxiety
39
What are the two approaches used with anti-thyroid drugs
Dose titration- where only anti-thyroid drugs are used. Doses are adjusted to achieve normalisation of thyroid hormone production Block and replace- where anti-thyroid drugs are given with thyroxine replacement
40
How do the two methods used with anti-thyroid drugs for hyperthyroidism compare
Both are equally effective Dose titration method associated with a lower rate of side effects
41
When is radioactive iodine used and what is the possible complication
First line for older patients with nodular goitres and hyperthyroidism Used when hyperthyroidism recurs after anti-thyroid drug therapy -HYpothyroidism may result
42
When is thyroidectomy used (removal of some or all of thyroid) What is the possible complication
When severe hyperthyroidism associated with a large goitre or concern about tumour development Also used when there are obstructive symptoms -Hypothyroidism may result