Thyroid gland clinical Flashcards

1
Q

Symptoms/signs of hypothyroidism (11) - think metabolism is lowered

A
Weight Gain
Lethargy
Cold intolerance
Constipation
Mental slowness
Depression
Myalgia/ muscle weakness
Dry Skin/Hair
Bradycardia
Slow reflexes
GOITRE

Severe hypothyroidism
-puffy face, large tongue, hoarse voice

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2
Q

Symptoms/signs of hyperthyroidism (14) - think metabolism is increased

A
Weight loss
Anxiety/irritability
Heat intolerance
Bowel frequency increase - diarrhoea
Frequent urination
Light periods
Sweating
Hair loss/thinning
Palpitations
Hyper-reflexia/tremors
GOITRE
Red/dry eyes
Osteoporosis
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3
Q

State the common tests of thyroid function and their interpretation, and the methods available for thyroid imaging.

A

TSH
FT4
FT3

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4
Q

Describe the levels of TSH, FT4 and FT3 in

  • primary hypothyroidism
  • subclinical (compensated) hypothyroidism)
  • secondary hypothyroidism
A

Raised TSH, Low FT4 & FT3

Raised TSH, Normal FT4 & FT3

Low (or normal) TSH, Low FT4 & FT3

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5
Q

How is congenital hypothyroidism identified/screened for

A

screened for after birth in heel prick test

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6
Q

Management of hypothyroidism in the newborn

A

Levothyroxine

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7
Q

Causes of primary hypothyroidism

  • congenital causes (2)
  • acquired causes (4)
A

Congenital

  • maldevelopment
  • dyshormonogenesis

Acquired

  • hashimoto’s thyroiditis/disease (autoimmune thyroiditis)
  • iatrogenic - from radioactive iodine, radiotherapy
  • chronic iodine deficiency
  • post partum thyroiditis
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8
Q

Hashimoto’s thyroiditis aka

A

Chronic immune/lymphocytic thyroiditis

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9
Q

Most common cause of primary hypothyroidism

A

Hashimoto’s disease (Autoimmune thyroiditis)

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10
Q

Causes of central (i.e. pituitary or hypothalamus) hypothyroidism

  • neoplastic (2)
  • infiltrative (1)
  • traumatic (3)
  • iatrogenic (2)
A

neoplastic

  • pituitary tumour (prevents TSH production)
  • hypothalamus trauma or tumour

infiltrative
-infection, e.g. TB, syphilis

traumatic

  • head trauma
  • pituitary apoplexy
  • sheehan’s syndrome (pituitary necrosis due to blood loss and hypovolemic shock post birth)

iatrogenic

  • pituitary surgery
  • pituitary radiotherapy
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11
Q

Signs of a pituitary mass causing hypothyroidism

A

Papilloedema

Bitemporal hemianopia

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12
Q

Biochemical investigations of primary hypothyroidism (e.g. Hashimoto’s thyroiditis) + typical findings of these (5)

hint: 2 autoantibodies

A

serum TSH - high

free serum T4 (FT4) - low

Autoantibodies

  • thyroid peroxidase (TPO) antibodies - elevated
  • anti-thyroglobulin antibodies - elevated

serum cholesterol - high

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13
Q

Treatment of primary hypothyroidism

A

Lifelong once daily levothyroxine (T4)

-initially 50 micrograms/day then adjust dose in increments of 12.5 to 25 micrograms to normalise TSH

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14
Q

Pathogenesis of Hashimoto’s disease (5)

A

Autoimmune destruction of thyroid involving thyroid peroxidase antibodies attacking the gland

  • lymphocytic infiltrate into the gland
  • destruction of thyroid follicles
  • apoptosis of thyroid epithelial cells
  • extensive fibrosis
  • Hurthle cell change
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15
Q

Special situations where treatment of hypothyroidism (referring to dose of levothyroxine) differs to usual

A

IHD
-start at lower dose and increase cautiously as can precipitate angina

Pregnancy
-need increased dose as increased demand for thyroid hormone in foetus

Myxedema (aka SEVERE HYPOTHYRDOIDISM) coma
-may need IV T3

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16
Q

What is myxoedema + what do you get it in

A

aka SEVERE HYPOTHYRDOIDISM

  • deposits of chains of sugar molecules (complex mucopolysaccharides) in the skin cause myxoedema
  • these compounds attract water, which lead to swelling

-swelling of face and esp lower legs

get it in hypo and hyperthyroidism (esp graves)

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17
Q

Levothyroxine doesn’t usually have side effects but over-treatment can lead to what side effect

A

Hyperthyroidism symptoms - sweating, chest pain, weight loss, palpitations

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18
Q

Why is there the need to increase dose of levothyroxine during pregnancy

A

as extra thyroid hormone needed for foetal nervous development

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19
Q

Causes of a goitre (6)

A

Physiological

  • puberty
  • pregnancy

Autoimmune thyroiditis

  • grave’s disease
  • hashimoto’s disease

Non-autoimmune thyroiditis

Iodine deficiency

Dyshormogenesis

Goitrogens

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20
Q

Types of goitres (5)

A

Multinodular goitre

Diffuse goitre (colloid or simple)

Cysts

Tumours (adenoma or carcinoma or lymphoma)

Miscellaneous causes (sarcoidosis, TB)

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21
Q

A solitary thyroid nodule has risk of what

A

malignancy

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22
Q

Investigations of a solitary thyroid nodule/ potential thyroid cancer (5)

A

TFTs - TSH, fT4

Ultrasound - differentiates benign v malignant

Fine needle aspiration (FNA) biopsy

Laryngoscopy - if vocal cords paralysed, suggests malignancy

Isotope thyroid scan - to look for hot/cold nodule

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23
Q

Nodules detected on a thyroid scan can be hot or cold

-what’s the difference

A

Thyroid scan involves giving radioactive iodine to see if there’s any region that’s over-producing or under-producing thyroid hormone

Hot nodule - a nodular region of the thyroid gland that takes up large amounts of radioactive iodine relative to the rest of the thyroid gland so it’s producing too much hormone and shows up darker

Cold nodule - nodule is composed of cells that do not make thyroid hormone (don’t absorb iodine) (i.e. non functioning nodule) so appears as defect/hole in the scan

24
Q

Do cold or hot solitary thyroid nodules have high risk of malignancy

25
Types of thyroid cancer (4)
(Well) Differentiated thyroid carcinoma (good prognosis) - papillary - follicular Anaplastic (poor prognosis; aggressive) Lymphoma (poor prognosis; rare) Medullary
26
Most common type of thyroid cancer
Papillary thyroid cancer
27
What underlies pathogenesis of most thyroid cancers
Genetic mutations
28
Papillary thyroid carcinomas often spread to where
local lymph nodes
29
Follicular thyroid carcinomas often spread to where
Lung/bone via blood rather than lymph
30
Thyroid cancer management - differentiated thyroid cancers (3) - anaplastic (1) - medullary (2) - lymphoma (2)
Differentiated - thyroidectomy - radioactive iodine ablation after surgery - long term levothyroxine - to suppress TSH Anaplastic -palliative surgery if possible but treatment based on chemoradiotherapy as it's aggressive and spreads so surgery not that helpful Medullary - thyroidectomy - then thyroid replacement (levothyroxine) - replacement rather than suppression as medullary cancer not TSH sensitive Lymphoma - chemotherapy - radiotherapy
31
Describe anaplastic thyroid cancer - characteristic - spread
Aggressive Locally invasive and can metastasise doesn't respond to radioactive iodine treatment
32
Thyroid lymphomas are rare and generally arise from pre-existing what
Hashimoto's thyroiditis
33
Medullary thyroid cancer is a tumour of what cells of the thyroid
parafollicular C cells
34
Medullary thyroid cancer is often associated with what genetic syndrome
Multiple endocrine neoplasia (MEN) type II
35
MEN type II (a genetic syndrome) predisposes you to what conditions (3)
Medullary thyroid cancer Phaeochromocytoma Hyperparathyrodism
36
Clinical features of thyroid cancer (5)
MAIN SIGN (may be the only sign people get)- palpable thyroid nodule - firm, immobile If advanced - hoarseness - dysphagia - dyspnoea - cervical lymphadenopathy
37
Describe the levels of TSH, FT4 and FT3 in - primary hyperthyroidism - subclinical (compensated) hyperthyroidism) - secondary hyperthyroidism
High FT4, FT3; Low TSH Normal FT4, FT3; Low TSH High FT4, FT3; High or normal TSH
38
Cause of secondary hyperthyroidism (rare)
Pituitary adenoma secreting TSH
39
Pathogenesis of grave's disease
Immune system produces TSH receptor antibodies which excessively stimulate thyroid gland to produce thyroid hormones, and consequently also causing hypertrophy of gland
40
Biochemical investigations of grave's disease (4)
serum TSH - low serum T4/T3 - high detectable TSH receptor antibodies - specific to grave's high thyroid uptake of radioactive iodine test
41
Untreated hyperthyroidism, particularly in older people, may result in what complications
cardiac arrhythmias, high-output cardiac failure, bone mineral loss
42
Symptoms (3) /signs (7) of grave's disease
Symptoms - heat sensitivity - sweating - palpitations/ fast irregular heartbeat --> AF Signs - Graves' ophthalmopathy - upper eyelid retraction, EXOPHTHALMOS, red etc - PRETIBIAL MYXOEDEMA (thyroid dermopathy) - acropachy - soft-tissue swelling of the hands and clubbing of the fingers - fine tremor - weight loss - DIFFUSE goitre
43
Causes of thyrotoxicosis without hyperthyroidism (3)
Post partum thyroditis Subacute (de Quervain's) thyroiditis Excessive therapeutic thyroxine
44
What is subacute (de Quervain's) thyroiditis
Painful swelling of the thyroid gland thought to be triggered by a viral infection, such as mumps or the flu fever and pain in the neck causes initial hyperthyroidism followed by transit hypothyroidism
45
Palpitations and shakes/temors associated with thyrotoxicosis can be treated with
beta blockers
46
Treatment of grave's disease (hyperthyroidism) (4)
Antithyroid drugs - carbimazole - propylthiouracil Radioactive iodine therapy +/- steroids Thyroidectomy ``` beta blockers (propanolol) -reduce symptoms of tremor, tachycardia and palpitations; doesn't cure the condition ```
47
Antithyroid drugs given for hyperthyroidism can be given in what different regimens + which is favoured
Titration regimen - start high dose then reduce gradually when thyroid levels improve Block-replace - blocking thyroid with constant dose then replacing with thyroxine when thyroid levels improve Titration regimen because less side effects
48
Who should radioactive iodine not be given to
Pregnant/breast feeding women
49
Possible complications of treatment of hyperthyroidism | -side effects of radioactive iodine, antithyroid drugs (propylthiouracil, carbimazole)
High dose radioactive iodine -risk of hypothyroidism Antithyroid drugs - propylthiouracil can be liver toxic - carbimazole and propylthiouracil may cause agranulocytosis
50
What is cretinism
severe hypothyroidism in the newborn - classically the result of maternal iodine deficiency --> physical and mental impairment
51
In early stages of Hashimoto's disease, damage to the thyroid follicles actually may cause a transient phase of what
hyperthyroidism due to release of thyroglobulin after damage of thyroid follicles
52
Histological features of Hashimoto's disease (4)
Dense lymphocyte and plasma cell infiltration --> lymphoid follicles Colloid content reduced Hurthle cell change - thyroid epithelium enlarge and develop eosinophilic granular cytoplasm Fibrosis
53
Histological features of Grave's disease (3)
Hyperplasia of acinar epithelium Reduced colloid content Accumulation of lymphocytes with lymphoid follicle formation
54
Why does grave's disease cause opthlamopathy
Because ocular fibroblast cells also have TSH receptor which the TSH receptor antibodies can attack
55
Are most follicular adenomas (thyroid tumour) functioning or non-functioning
Non-functioning
56
Follicular adenoma v follicular carcinoma
Follicular adenoma - encapsulated tumour Follicular carcinoma - malignant cells breach capsule and spread outmatch thyroid
57
What thyroid cancer is characterised by psammoma bodies
papillary carcinoma