Clinical Thyroid Disease Flashcards

1
Q

What are some examples of thyroid diseases?

A

Hypothyroidism

Goitre

Thyroid cancer

Hyperthyroidism

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2
Q

Give a summary of the hormones involved with the thyroid gland?

A
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3
Q

What is the clinical manifestation of hypothyroidism?

A
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4
Q

What is the clinical presentation of hyperthyroidism?

A
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5
Q

Compare and contrast the clinical presentation of hyper and hypothyroidism?

A
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6
Q

What are the different classifications of hypothyroidism?

A
  • Primary (thyroid)
    • Raised TSH, low FT4 and low FT3
  • Subclinical (compensated)
    • Raised TSH, normal FT4 and FT3
  • Secondary (pituitary)
    • Low TSH, low FT4 and FT3
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7
Q

Where is the pathology that causes primary hypothyroidism?

A

Thyroid gland

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8
Q

Where is the pathology that causes secondary hypothyroidism?

A

Pituitary gland

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9
Q

What TSH, FT3 and FT4 levels are seen in primary hypothyroidism?

A

Raised TSH

Low FT3

Low FT4

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10
Q

What TSH, FT3 and FT4 levels are seen in subclinical hypothyroidism?

A

Raised TSH

Normal FT3

Normal FT4

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11
Q

What TSH, FT3 and FT4 levels are seen in secondary hypothyroidism?

A

Low TSH

Low FT3

Low FT4

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12
Q

What are the 2 most common endocrine conditions?

A

1) Diabetes
2) Hypothyroidism

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13
Q

Does hypothyroidism affect men and woman equally?

A

No, affects more woman

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14
Q

What are some causes of primary hypothyroidism?

A

Congenital

  • developmental: agenesis, maldevelopment
  • dyshormonogenesis: trapping, organification

Acquired

  • autoimmune thyroid disease: hashimotos, atrophic
  • iatrogenic:
  • postoperative/post-radioactive iodine
  • external RT for head and neck cancers
  • antithyroid drugs (such as Lithium)
  • chronic iodine deficiency
  • post-subacute thyroiditis
  • post-partum thyroiditis
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15
Q

Are babies screened for hypothyroidism?

A

Yes, all babies are

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16
Q

What is the incidence of congenital hypothyroidism?

A

1/3500

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17
Q

What are some causes of secondary hypothyroidism?

A
  • Pituitary/hypothalamic damage
    • Pituitary tumour
    • Craniopharyngioma
    • Post pituitary surgery or radiotherapy
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18
Q

How does hormone secretion change in hypothyroidism?

A
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19
Q

What investigations are done for hypothyroidism?

A
  • TSH/fT4
  • autoantibodies
  • TPO (thyroid peroxidase antibodies)
  • FBC (MCV raised)
  • lipids (hypercholesterolaemia)
  • hyponatremia due to SIADH
  • increased muscle enzymes (ALT, CK)
  • hyperprolactinaemia
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20
Q

What autoantibody is investigated in hypothyroidism?

A

TPO (thyroid peroxidase antibodies)

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21
Q

What does TPO stand for?

A

Thyroid peroxidase antibodies

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22
Q

What is used for the treatment of hypothyroidism?

A
  • Levothyroxine (T4) tablets
  • Liothyronine (T3) tablets
  • Combination of T3 and T4 has no benefit from studies
  • After stabilisation, annual testing of TSH
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23
Q

What is the first line treatment for hypothyroidism?

A

Levothyroxine tablets (T4)

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24
Q

What is the initial dose of levothyroxine for hypothyroidism?

A

1.6mcg/kg

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25
Q

How does ischaemic heart disease impact the initial treatment for hypothyroidism?

A

Lower dose of levothyroxine used (25mcg) and increased cautiously

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26
Q

When should treatment be given for subclinical hypothyroidism?

A
  • if TSH > 10
  • or TSH > 5 with symptoms: therapy should be trialled for 6 months
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27
Q

If subclinical hypothyroidism is diagnosied, when should tests be repeated?

A

2-3 months later with TPO antibodies

28
Q

How does pregnancy impact treatment for hypothyroidism?

A
  • increase LT4 dose by about 25% and monitor closely
  • aim to keep TSH in normal range (<2.5mU/L) and FT4 in high normal range
29
Q

What is inadequately treated hypothyroidism during pregnancy associated with?

A

Increased foetal loss and lower IQ

30
Q

What is goitre?

A

Swelling of the thyroid gland

31
Q

What is swelling of the thyroid gland called?

A

Goitre

32
Q

What are some causes of goitre?

A
  • physiological: puberty, pregnancy
  • autoimmune: graves disease, hashimoto’s disease
  • thyroiditis: acute (de Quervian’s), chronic fibrotic (Reidel’s)
  • iodine deficiency (endemic goitre)
  • dyshormogenesis
  • goitrogens
33
Q

What are some different goitre types?

A
  • multinodular goitre
  • diffuse goitre: colloid, simple
  • cysts
  • tumours: adenomas, carcinoma, lymphoma
  • miscellaneous: sarcoidosis, tuberculosis
34
Q

What tumours can cause goitre?

A

Adenoma

Carcinoma

Lymphoma

35
Q

What is solitary nodule thyroid?

A

Defined as palpable discrete swelling within an otherwise normal gland

36
Q

What risk comes with solitary nodule thyroid?

A

Risk of malignancy (5% chance)

37
Q

What investigations are done for solitary nodule thyroid?

A
  • thyroid function test: solitary toxic nodule
  • ultrasound: useful in differentiating between benign and malignant
  • fine needle aspiration (FNA): Thy1 is inadequate, Thy2 is benign to Thy5 which is cancer
38
Q

What is the most common endocrine malignancy?

A

Thyroid cancer

39
Q

What are the different classifications of thyroid cancer?

A
  • Papillary
    • Commonest
    • Multifocal, local spread to lymph nodes
    • Good prognosis
  • Follicular
    • Usually single lesion
    • Metastases to lung/bone
    • Good prognosis if resectable
40
Q

Which form of thyroid cancer is the most common, papillary or follicular?

A

Papillary

41
Q

Where does papillary thyroid cancer often spread to?

A

Local spread to lymph nodes

42
Q

Where does follicular thyroid cancer often metastasis to?

A

Lung or bone

43
Q

What is the management of thyroid cancer?

A
  • near total thyroidectomy
  • high dose radioiodine (ablative)
  • long term suppressive doses of thyroxine
  • follow u
44
Q

What surgery can be done to treat thyroid cancer?

A

Thyroidectomy

45
Q

Other than follicular and papillary thyroid cancer, what are some other thyroid cancers?

A

Anaplastic

Lymphoma

Medullary thyroid cancer

46
Q

What does anoplastic thyroid cancer not respond to?

A

Radioiodine

47
Q

What is lymphoma thyroid cancer best treated with?

A

External RT, combined with chemotherapy

48
Q

What does the tumour that causes medullary thyroid cancer arise from?

A

Parafollicular C cells

49
Q

What genetic syndrome is medullary thyroid cancer associated with?

A

MEN2

50
Q

What is the treatment for medullary thyroid cancer

A

Total thyroidectomy

No role for radioiodine

51
Q

How does hyperthyroidism impact hormones?

A
52
Q

What are some causes of hyperthyroidism?

A
  • primary: grave’s disease (70%), toxic multinodular goitre (20%), toxic adenoma
  • secondary: pituitary adenoma secreting TSH
  • thyrotoxicosis without hyperthyroidism: thyroiditis, excess T4 administration
53
Q

What is the most common cause of primary hyperthyroidism?

A

Grave’s disease (70%)

54
Q

What is thyrotoxicosis?

A

Excess thyroid hormone in the body

55
Q

What are some causes of thyrotoxicosis without hyperthyroidism?

A

Destructive thyroiditis

Excessive thyroxine administration

56
Q

What is the M:F ratio of Grave’s disease?

A

1:5 (more females affected)

57
Q

What kind of condition is Grave’s disease?

A

Autoimmune condition

58
Q

What antibodies are present in grave’s disease?

A

Thyroid peroxidase antibodies

TSH receptor antibodies

59
Q

What is the diagnosis of Grave’s disease done by?

A

Hyperthyroidism present

Thyroid antibodies (TSH receptor antibodies)

60
Q

What is the most common cause of thyrotoxicosis in the elderly?

A

Multinodular goitre

61
Q

What triggers subacute (de Quervain’s) thyroiditis?

A

Viral trigger (enteroviruses, coxsackie)

62
Q

What is the clinical presentation of subacute (de Quervain’s) thyroiditis?

A

Painful goitre

Maybe fever/myalgia

ESR increased

63
Q

What treatment may subacute (de Quervain’s) thyroiditis require?

A

Short term steroids and NSAIDs

64
Q

What is the management of hyperthyroidism?

A
  • radioiodine (RAI)
  • anti-thyroid drugs (ATD): carbimazole, propylthiouracil
  • beta blockers for symptoms
65
Q

What are examples of anti-thyroid drugs?

A

Carbimazole

Propylthiouracil

66
Q

What are some concerns for patients with subclinical hyperthyroidism?

A
  • bones: decreased density postmenopausal
  • atrial fibrillation: 3x increased risk in over 60s
67
Q

What treatment is considered for subclinical hyperthyroidism and when?

A
  • ATD/RAI if persistent
  • especially in elderly or those with increased cardiac risk