Clinical Thyroid Disease Flashcards by Sophia Boyce

Name as many symptoms of hypothyroidism as you can (10)

Weight gain
Lethargy
Feeling cold
Constipation
Heavy periods
Dry skin/hair
Bradycardia
Slow reflexes
Goitre
Severe - puffy face, large tongue, hoarseness, coma

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What are the 3 types of hypothyroidism and where are they based?

Primary - thyroid
Secondary - pituitary
Subclinical - compensated

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What are the thyroid function test results in each type of hypothyroidism?

Primary:
- Raised TSH; Low FT4 + FT3
Secondary:
- Low TSH; Low FT4 + FT3
Subclinical:
- Raised TSH; Normal FT4 + FT3

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What is the most common type of hypothyroidism?

Primary (only 1-2% secondary)

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What is subclinical hypothyroidism?

An early, mild form of hypothyroidism

Normal FT4 and FT3 as TSH has managed to compensate (even the TSH is only lil bit above normal)

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Is hypothyroidism more prevalent in women or men?

Women (1.9% v 0.1% in men)

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What percentage of the population have subclinical hypothyroidism? What percentage or women over 60 have it?

10%

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What is the prevalence of congenital hypothyroidism?

1 in 3500 births

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What problems can arise in congenital primary hympothyroidism?

DEVELOPMENTAL - agenesis/maldevelopment
DYSHORMONOGENESIS - trapping/organification of iodide/dehalogenase deficiency (deiodinase enzyme)

(‘growth retardation and mental retardation’)

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How do we screen for thyroid problems at birth?

Heel prick test

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Give 4 general acquired causes of primary hypothyroidism

Autoimmune thyroid disease
Iatrogenic
Chronic iodine deficiency
Post-subacute thyroiditis

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What are types of autoimmune thyroid disease?

Hashimotos

Atrophic

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What are the iatrogenic causes of primary hypothyroidism?

Post-op/post-radioactive iodine
External RT for H+N cancer
Antithyroid drugs, amiodarone, lithium, interferon

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Give an example of post-subacute thyroiditis?

Post-partum thyroiditis

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What is the major cause for secondary/tertiary hypothyroidism?

Pituitary/hypothalamic damage

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Give 5 underlying causes for pituitary/tertiary hypothyroidism

Pit tumour
Craniopharyngioma
Post pit surgery or radiotherapy
Sheehan’s syndrome
Isolated TRH deficiency

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What is Sheehan’s syndrome?

Damage of pituitary gland during childbirth (due to low BP/haemhorrage during or post-partum)

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Investigations for hypothyroidism?

TSH/fT4 (thyroid function tests)

Autoantibodies: TPO (thyroid peroxidase antibodies)

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What is the standard treatment for hypothyroidism?

Levothyroxine (T4) tablets

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What is the dosage plan for levothyroxine?

50mcg/day, increase after 2 weeks to 100mcg

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For how long do u increase the dose of levothyroxine (T4)?

Until TSH is normal, or fT4 in normal range in secondary

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How often should TSH be tested after stabilisation?

Annually

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When should T4 be taken?

Same time everyday on empty stomach

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Has there been any proven benefit to T3 treatment/T3 combined with T4?

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In what patients should you be more careful with treatment?

IHD Pregnancy Postpartum thyroiditis Myxedema coma

What should be done in patients with IHD?

Start at lower dose 25mcg and increase cautiously (risk of angina/HF)

What should be done in patients who r pregnant?

Most will need an increase in LT4 dose (25%)

What should be done in patients with post-partum thyroiditis?

Trial withdrawal and measure TFT's in 6 wks

What should be done in patients with myxedema coma?

V rare emergency, may need IV T3 (steroid)

When should trial treatment for subclinical hypothyroidism be consdered?

TSH > 10 TSH > 5 w positive thyroid antibodies TSH elevated with symptoms Women pregnant/planning pregnancy

What is a normal FT4 and TSH level?

TSH: 0.3-3.3 FT4: 10-25

Give 2 risk of over treatment for subclinical hypothyroidism

Osteopenia | Atrial fib

Describe goitre

Swelling of thyroid gland causing swelling of neck

Name 2 physiological causes of goitre

Puberty | Pregnancy

Name 2 autoimmune causes of goitre

Graves | Hashimotos

Name 2 forms of thyroiditis which cause goitre

``` Acute (de Quervain's) Chronic fibrotic (Reidel's) ```

Name 3 other causes of goitre

Iodine deficiency Dyshormonogenesis Goitrogens

What are the types of goitre?

- Multinodular - Diffuse (colloid, simple) - Cysts - Tumours - Misc (sarcoidosis, TB)

What is there a risk of with a solitary nodule thyroid?

Malignancy - 5%

In who is there a risk of malignancy associated with solitary nodule thyroid?

Children Adults <30 or >60 Prev H+N irradiation Pain, cervical lymphadenopathy

What investigations are done for solitary thyroid nodules?

Thyroid function test USS FNA Isotope scanning if low TSH - hot nodule

What is the diff between hot and cold nodules?

``` Hot = producing too much hormone (to absorb iodine); hyperthyroidism Cold = not producing any hormone (not absorbing iodine so not composed of thyroid cells); higher risk of cancer; cyst or adenoma ```

What is the commonest form of thyroid cancer?

Papillary

Describe the nature and spread of thyroid cancer?

Multifocal | Local spread to lymph nodes

What is the prognosis like for papillary thyroid cancer?

Goood

Describe the nature and spread of follicular thyroid cancer?

Usually single lesion | Mets through blood to lung/bone

What is the prognosis like for follicular thyroid cancer?

Good if resectable

What factors cause thyroid cancer prognosis to become poorer?

- <16 yrs; >45yrs - spread outside capsule + mets - TNM stage

What is the management plan for thyroid cancer?

Near total thyroidectomy (if high risk - lobectomy if low) High dose radioiodine Long term suppressive thyroxine (DEBULK, DESTROY, SUPPRESS) Follow up - thyroglobulin yrly; iodine scan of body

What is there a risk of with overtreating of radioiodine?

Developing leukaemia - important to weigh up whether to leave someone w a lil bit of thyroid cancer n lower risk of leukaemia)

Give 3 more rare thyroid cancers

Anaplastic Lymphoma Medullary

What is the prognosis for anaplastic thyroid cancer?

V poor due to its aggressive and locally invasive nature | Doesnt respond to radioidone - external RT may help briefly

How could thyroid lymphoma arise and how is it treated?

From pre-existing hashimotos | External RT w chemo

What does medullary thyroid cancer arise from?

Parafollicular C cells; associated w MEN2

What does medullary thyroid cancer cause in serum and what is the treatment?

Serum calcitonin levels raised | Treatment is total thyroidectomy, no radioiodine (variable prognosis)

Name as many symptoms of hyperthyroidism as u can (10)

``` Weight loss Anxiety/irritability Heat intolerance Bowel infrequency Light periods Sweaty palms Palpitations Hyperreflexia/tremors Goitre Thyroid eye symptoms/signs ```

What are the typical trends in thyroid function tests in hyperthyroidism?

``` T3/T4 = elevated TSH = suppressed ```

What are the commonest causes for primary hyperthyroidism?

- Graves (70%) - Toxic Multinodular Goitre (20%) - Toxic adenoma

What is a cause for secondary thyrotoxicosis?

Pituitary adenoma secreting TSH

What are 2 causes of thyrotoxicosis w/o hyperthyroidism?

- Destructive thyroiditis (post-partum, subacute (de Quervain's), amiodarone) - Excessive thyroxine administration

Which gender is graves disease more common in?

Women

What type of condition is Graves

AUTOIMMUNE condition

What antibodies are seen in Graves

Thyroid peroxidase | TSH receptor

What are some presenting signs seen in Graves?

Exopthalmos (enlarged, red eyes) Diffuse goitre Hyperthyroid symptoms

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

Multi-nodular goitre

Discuss subacute (de Quervain's) thyroiditis

<50 yrs Viral trigger e.g. enterovirus Painful goitre +/- fever/myalgia May require short term steroids/NSAIDs

Management of hyperthyroidism?

Beta blockers to manage symptoms Anti-thyroid drugs Radioiodine Surgery (only large goitres/other options unavailable)

What are the 2 ATDs?

Carbimazole (preferred) | Propylthiouracil (prefered in pregnancy)

Side effects of ATDs?

Rash | Agranulocytosis 1:500 (potentially fatal - confirm patient has adequate neutrophil b4 treating)

What is the usual ATD regimen?

Titration regimen; 12-18 months

What are the selected cases for long term low dose ATD?

- elderly - cardiac complications - unwilling for RAI

Who cant radioiodine patients come into contact with for 4 wks?

<18 children | Pregnant women

What is the risk of hypothyroidism in radioiodine treatment?

70%

TSH: 15 FT4: 9 DIAGNOSIS?

Primary hypo TSH raised FT4 low (TSH tried to produce more FT4 but the thyroid isn't working so will not physically produce any more FT4)

TSH: 0.5 FT4: 9 DIAGNOSIS?

Secondary hypo TSH low side of normal FT4 low

TSH: 15 FT4: 12 DIAGNOSIS?

Subclinical hypo TSH raised FT4 normal

Clinical Thyroid Disease Flashcards

(76 cards)