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
    • Incidence of congenital hypothyroidism is 1/3500
      • All babies in UK screened
  • 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 trialed 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
  • Increased levothyroxine requirements during pregnancy
  • Inadequately treated hypothyroidism linked with increased foetal loss and lower IQ
  • At diagnosis of pregnancy
    • 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
  • Prognosis poorer
    • Age <16 or >45, tumour size, spread outside thyroid capsule and metastases, TNM stage
  • Near total thyroidectomy
  • High dose radioiodine (ablative)
  • Long term suppressive doses of thyroxine
  • Follow up
    • Thyroglobulin

Whole body iodine scanning

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
    • Destructive thyroiditis
    • Excessive thyroxine 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
  • RAI (radioiodine)
    • High dose ablative
    • Patients usually choose ATD before RAI
    • Treat with ATP (stop 4-7 days before and after)
  • ATD (anti-thyroid drugs)
    • Carbimazole
    • Propylthiouracil
  • Sx
  • Beta blockers
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 bone density postmenopausal, no clear fracture data
  • Atrial fibrillation
    • 3x increased risk in over 60s
67
Q

What treatment is considered for subclinical hyperthyroidism and when?

A

ATP/RAI if persistent, especially in elderly or those with increased cardiac risk