7. Thyrotoxicosis / Hyperthyroidism Flashcards

1
Q

What is the difference between thyrotoxicosis and hyperthyroidism?

A

Thyrotoxicosis - This is when there is an excess of thyroid hormone in the blood (regardless of cause)

Hyperthyroidism - This is when there is an overproduction of thyroid hormone from the thyroid gland.

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2
Q

What is the difference between primary and secondary hyperthyroidism?

A

Primary is due to abnormal thyroid physiology

Secondary is due to abnormal hypothalamus / pituitary physiology

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3
Q

What is exophthalmos? What causes it? What does it indicate?

A

It is anterior bulging of the eyes out of the socket in Graves Disease. This is due to inflammation, swelling and hypertrophy of the tissue behind the eyeball

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4
Q

What is pretibial myxoedema? What condition is it indicative of?

A

Pretibial Myxoedema is a dermatological condition where there are deposits of mucin under the skin on the anterior aspect of the leg (the pretibial area). This gives a discoloured, waxy, oedematous appearance to the skin over this area. It is specific to Grave’s disease and is a reaction to the TSH receptor antibodies.

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5
Q

How do the lab test results for primary and secondary hyperthyroidism differ?

A

Primary - High Th4, High Th3 and Low TSH

Secondary - High Th4, High Th3 and Normal or High TSH

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6
Q

What are the causes of hyperthyroidism?

A

1) Graves Disease
2) Multinodular Goitre
3) Solitary Toxic Nodule
4) Thyroiditis

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7
Q

What is Graves Disease?

A

It is where the body produces antibodies that mimic TSH and stimulate the TSH receptors on the thyroid, causing hyperthyroidism.

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8
Q

How does Graves Disease lead to eye problems?

A

The antibodies that mimic TSH may also attack the ocular muscles , leading to both vision problems and exophthalmos

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9
Q

If someone says there eyes feel grainy, what condition are you thinking of?

A

Graves Disease

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10
Q

What is the risk with Graves Disease and pregnancy?

A

Even if you’ve had graves disease, and the treatment has brought you back down to normal levels of thyroid hormone, there is a risk that you still have graves antibodies in your blood, which can cause problems for the Fetus during or after pregnancy

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11
Q

What is the issue with graves disease and men specifically?

A

It can cause a marked reduction in sperm count, resulting in reduced fertility. The sperm count usually returns to normal once the thyroid condition has been treated.

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12
Q

What is multi nodular goitre?

A

This is a condition where the patient produces multiple thyroid nodules, which contain abnormal thyroid tissue so that the thyroid gland ends up producing more thyroid hormone than normal. They are independent of TSH regulation, so produce thyroid hormones at their own will. They are usually non-cancerous

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13
Q

What is Plummers Disease?

A

This is another name for multinodular goitre

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14
Q

How long does it take for a multinodular goitre to go away by itself?

A

It never does.

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15
Q

What are the causes of thyroiditis?

A
  • De Quervain’s Thyroiditis
  • Hashimoto’s Thyroiditis
  • Postpartum thyroiditis
  • Silent (painless) thyroiditis
  • Drug-induced thyroiditis
  • Radiation-induced thyroiditis
  • Acute or infectious thyroiditis
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16
Q

What is De Quervain’s Thyroiditis?

A

This is caused by a viral infection, causing fever, neck pain, pysphagia and features of hyperthyroidism. There is a hyperthyroid phase followed by hypothyroid phase as the TSH level falls due to negative feedback.

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17
Q

How is De Quervains Thyroiditis treated?

A

It is a self-limiting condition and supportive treatment with NSAIDs for pain and inflammation and beta blockers for symptomatic relief of hyperthyroidism is usually all that is necessary.

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18
Q

Who commonly gets De Quervains Thyroiditis?

A

It’s most commonly seen in women aged 20 to 50.

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19
Q

What is Hashimoto’s Thyroiditis?

A

Hashimoto’s thyroiditis is caused by the immune system attacking the thyroid gland, which damages it and makes it swell.

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20
Q

Does Hashimoto’s thyroiditis cause hyperthyroidism or hypothyroidism?

A

Initially it can cause a sudden release of thyroid hormones, resulting in hyperthyroidism, however overtime, as the thyroid gland becomes more and more damaged, it struggles to produce the hormones, so it causes hypothyroidism

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21
Q

When do people normally present with Hashimoto’s thyroiditis? Why the wait?

A

It may take months or even years for the condition to be detected because it progresses very slowly. Symptoms usually first start between the ages of 30 to 50 and the condition sometimes runs in families.

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22
Q

What is post-partum thyroiditis? After how long do they get it?

A

Postpartum thyroiditis is an uncommon condition that can affect women who have recently given birth. In postpartum thyroiditis, the immune system attacks the thyroid within around 6 months of giving birth.

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23
Q

Does post-partum thyroiditis thyroiditis cause hyperthyroidism or hypothyroidism?

A

Initially there is a temporary rise in thyroid hormone levels (thyrotoxicosis) and symptoms of an overactive thyroid gland. Then, after a few weeks, the gland becomes depleted of thyroid hormone. This leads to low thyroid hormone levels and symptoms of an underactive thyroid gland. However, not every woman with postpartum thyroiditis will go through both these phases.

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24
Q

How is post-partum thyroiditis treated?

A

Treatment depends on the phase of thyroiditis and degree of symptoms that a patient has.

Women presenting with thyrotoxicosis may be treated with beta blockers to decrease symptoms such as palpitations and tremors. As symptoms improve, the medication can be reduced and stopped since the thyrotoxic phase is transient.

The hypothyroid phase may be treated with thyroid hormone replacement. If the hypothyroidism is mild, and the patient has few, if any, symptoms, no therapy may be necessary. If thyroid hormone therapy is started, treatment should be continued for approximately 6-12 months and then reduced to see if thyroid hormone is required permanently.

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25
Q

What is silent thyroiditis?

A

Silent thyroiditis is very similar to postpartum thyroiditis, but it can affect men and women, and is not related to giving birth.

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26
Q

What is the course of thyroid levels / symptoms like in silent thyroiditis?

A

Like postpartum thyroiditis, there may be a phase of high thyroid hormone levels (thyrotoxicosis) causing symptoms of an overactive thyroid gland. This may be followed by symptoms of an under-active thyroid gland, before the symptoms go away in 12 to 18 months.

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27
Q

How is silent thyroiditis treated?

A

The same as for other types of thyroidits. If symptomatic in hyperthyoid phase, give beta blockers for symptoms.

When in hypothyroid stage, if it’s only mild / have no symptoms, then give nothing. If it’s more serious, then give levothyroxine. Make sure to check thyroid levels over the first 12-18 months to constantly reassess levels.

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28
Q

What is drug-induced thyroiditis?

A

Certain drugs can damage the thyroid and cause symptoms of hyperthyroidism (but can also cause symptoms of hypothyroidism in others)

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29
Q

Which drugs can commonly cause hyperthyroidism?

A

The main drugs that we see in the western world that cause hyperthyroidism are;

  • Interferon
  • Amiodarone
  • Lithium
30
Q

What is interferon usually used for?

A
  • Hep. C treatment

- Cancer

31
Q

What is Amiodarone usually used for?

A

Arrythmias

32
Q

What is lithium usually used for?

A

Bipolar Disorder

33
Q

What is radiation-induced thyroiditis?

A

The thyroid gland can sometimes be damaged by radiotherapy or radioactive iodine treatment given for an overactive thyroid gland.

This can either lead to symptoms of an overactive thyroid gland or symptoms of an underactive thyroid gland.

34
Q

What is acute or infectious thyroiditis usually caused by?

A

Bacteria

35
Q

Who is acute or infectious thyroiditis typically seen in?

A

It’s rare, and only normally seen in those with a weakened immune system or, in children, a problem with the development of the thyroid.

36
Q

How is acute or infectious thyroiditis treated?

A

Antibiotics

37
Q

How common is hyperthyroidism in men and women?

A

Women - 2% of population
Men - 0.2% of population

10x difference

38
Q

What are the symptoms of hyperthyroidism?

A
  • Weight loss even though good appetite, or always hungry
  • Tachycardia = palpitations; (can cause AF, atrial fibrillation)
  • Sweating, heat intolerance
  • Anxiety and Irritability, mood swings
  • Frequent bowel action (diarrhoea)
  • Potentially goitre (neck lump)
  • Sexual dysfunction
39
Q

What are the clinical signs of hyperthyroidism?

A
  • High pulse rate and BP > need to check heart function
  • Atrial fibrillation: 3x risk in > 60s
  • Agitation
  • Tremor
  • Onycholysis (painless detachment of nail from nail bed)
  • Hyperreflexia (sharp,over-exaggerated reflexes)
40
Q

What are the unique features of Graves Disease?

A

These features all relate to the presence of TSH receptor antibodies.

  • Diffuse Goitre (without nodules)
  • Thyroid Eye Disease (Bilateral Exophthalmos and Ophthalmoplegia, blurred vision)
  • Pretibial Myxoedema
  • Acropachy
41
Q

What are the risks of thyroid eye disease?

A

Both occur as a result of increased intraocular pressure.

  • optic nerve damage exposure
  • corneal ulceration
42
Q

How can you test thyroid eye disease?

A
  • General inspection from head on view and side view
  • Lid lag test
  • Double H test
43
Q

What is Acropathy?

A

Soft tissue swelling of hands and clubbing of fingers

44
Q

What is Ophthalmoplegia?

A

Paralysis or weaking of eye muscles

45
Q

If someone had unilateral exophthalmos, what condition are you thinking of?

A

You can rule out graves as if it was that, it would be bilateral.

Instead, it could be a malignancy for example.

46
Q

What clinical sign is indicative of Toxic Multinodular Goitre?

A

Goitre with firm nodules (and usually over the age of 50)

47
Q

What is thyroid storm? What are the signs?

A

It is a more severe presentation of hyperthyroidism, otherwise known as thyrotoxic crisis.

48
Q

What are the signs of thyroid storm?

A

Pyrexia, tachycardia and delirium

49
Q

How is thyroid storm treated?

A

It requires admission for monitoring and is treated the same way as any other presentation of thyrotoxicosis, although they may need supportive care with fluid resuscitation, anti-arrhythmic medication and beta blockers.

50
Q

What are the treatments for hyperthyroidism?

A
  • Carbimazole
  • Propylthiouracil
  • Radioactive Iodine
  • Beta-blockers
  • Surgery
51
Q

What is Carbimazole? When is it used?

A

It is the first-line anti-thyroid drug. It is usually successful in treating patients with Grave’s Disease, leaving them with normal thyroid function after 4-8 weeks. This stops iodine uptake, reducing the amount of the hormone the gland can produce.

52
Q

Once normal thyroid hormone levels are achieved with carbimazole, what are the 2 options?

A

They continue on maintenance carbimazole and either:

  • The dose is carefully titrated to maintain normal levels (known as “titration-block”)
  • The dose is sufficient to block all production and the patient takes levothyroxine titrated to effect (known as “block and replace”)
53
Q

In what cirumstance is ‘block and replace’ with cabimazole contraindicated?

A

For someone who is pregnant, or at risk of becoming pregnant.

54
Q

If you are given carbimazole, is it for life?

A

No, complete remission and the ability to stop taking carbimazole is usually achieved within 18 months of treatment.

55
Q

How does propylthiouracil work?

A

It is the second-line anti-thyroid drug. It stops iodine and thyroid peroxidase (TPO) from interacting with the thyroglobulin.

56
Q

Why is propylthiouracil the second-line antithyroid drug? What is the first line drug?

A

First line is carbimazole.

Propylthiouracil is second line as there is a small chance of severe hepatic reactions, including death.

57
Q

Name the 2 antithyroid drugs and give their side effects.

A

Carbimazole and Propylthiouracil

  • Rash, itching (3-5%)
  • Arthralgia
  • Nausea and vomiting
  • Mild leucopenia
  • Agranulocytosis
58
Q

What is leucopenia?

A

Decrease in white blood cells

59
Q

What is agranulocytosis?

A

It is a severe leukopenia (reduction in white blood cells)

60
Q

If you start someone on an anti-thyroid medication, what must you tell them and why?

A

To report any signs of an infection to a doctor, especially if its a sore throat.

This is because mild leucopenia and agranulocytosis are 2 serious side effects of these drugs, and the anti-thyroid drug would need to be stopped immediatly if they were found to be suffering from either of these side effects.

61
Q

What happens if you are on antithyroid drugs and become pregnant?

A
  • As it crosses placenta, it is titrated down to the lowest possible dose.
  • If you are on carbimazole, then it is swapped for propylthiouracil as soon as possible. This is the drug of choice for when trying to conceive + first 3 months of pregnancy. If this can’t be done however, you can stick with carbimazole.
62
Q

How does radioactive iodine work as a treatment for hyperthyroidism?

A

It involves drinking a single dose of radioactive iodine. This is taken up by the thyroid gland and the emitted radiation destroys a proportion of the thyroid cells. This reduction in functioning cells results in a decrease of thyroid hormone production and thus remission from hyperthyroidism.

63
Q

What is the radioactive iodine?

A

Radioiodine-131

64
Q

What is a complication of radioactive iodine?

A

Remission can take 6 months and patients can be left hypothyroid afterwards and require levothyroxine replacement.

65
Q

What is the link between radioactive iodine and infertility?

A

It does NOT cause infertility

66
Q

What are the 3 rules for the patient regarding treatment with radioactive iodine?

A
  • Must not be pregnant and are not allowed to get pregnant within 6 months
  • Must avoid close contact with children and pregnant women for 3 weeks (depending on the dose)
  • Limit contact with anyone for several days after receiving the dose
67
Q

How is someone scheduled for radioactive-iodine treatment prepared?

A

They should stop taking their anti-thyroid drugs 5-7 days before

68
Q

What may worsen after radioactive iodine treatment?

A

Graves opthamology may worsen. However,

  • It is often transient
  • Commonly effects smokers
  • Reduced by prednisolone
69
Q

Why are beta-blockers sometimes given to those with hyperthyroidism?

A

It treats the adrenalin related symptoms of hyperthyroidism. They do not actually treat the underlying problem but control the symptoms whilst the definitive treatment takes time to work. They are particularly useful in patients with thyroid storm.

70
Q

Which beta-blocker is good to give for those with certain types of hyperthyroidism? Why that one specifically?

A

Propranolol is a good choice because it non-selectively blocks adrenergic activity as opposed to more “selective” beta blockers that work only on the heart.

71
Q

What is a definitive option to treat hyperthyroidism? What is the complication of it?

A

Surgical removal of either the whole thyroid or just the toxic nodules. This effectively stops the production of thyroid hormone, however the patient will be left hypothyroid post thyroidectomy and require levothyroxine replacement for life

72
Q

What are complications of a thyroidectomy?

A
  • Permanent parathyroid damage (can lead to hypocalcemia)
  • Vocal cord paralysis (damaged right laryngeal nerve)
  • Bleeding
  • Keloid scars (scars that are raised)