Clinical Thyroid Disease Flashcards by Peter Savage

What does the hypothalamus secrete to stimulate the thyroid?

TRH

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What does the thyroid secrete?

T3 Triiodothyronine

T4 Thyroxine

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What are the symptoms of hypothyroid?

Weight gain
Goitre 
Mood changes 
Dry skin/hair 
Heavy periods
Feeling Cold
Lethargy 
Bradycardia

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What are the symptoms of severe hypothyroid?

Puffy face
Large tongue
Hoarseness
Coma

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What are the symptoms of hyperthyroid?

Weight loss
Overheating
Anxiety/irritability
Bowel frequency 
Sweaty palms
Palpitations
Tremors
Goitre
Thyroid eye signs

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How does primary Hypothyroidism present hormonally?

Raised TSH

Low T3, T4

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How does subclinical Hypothyroidism present hormonally?

Raised TSH

Normal T3, T4

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How does secondary Hypothyroidism present hormonally?

Low TSH

Low T3, T4

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How common is hypothyroidism?

2% of women

0.1% of men

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How common is congenital hypothyroidism?

1:3500

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What are the causes of primary hypothyroidism?

Congenital
- Developmental
- Dyshormonogenesis
Acquired

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What are the causes of acquired primary Hypothyroidism?

Autoimmune (hashimotos)
Iatrogenic
Chronic iodine deficiency
Post-subacute thyroiditis

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What procedures have a risk of causing hypothyroidism?

Post-op
Post-radiotherapy
Post radioactive iodine
Antithyroid drugs
Amiodarone
Lithium
Interferon

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What are the causes of secondary/tertiary hypothyroidism?

Pituitary tumour
Craniopharyngioma
Post-pituitary surgery
Sheehan's syndrome
Isolated THR deficiency

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What is the effect of low T3/T4 on TSH, TRH?

Elevated TSH

Elevated TRH

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How is hypothyroidism investigated?

TSH
T4
Thyroid peroxidase antibodies
(FBC, Lipids, Na+, ALT, PLT)

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How is hypothyroidism treated?

Levothyroxine (T4) at 50mcg/day → 100mcg
Until dose normal
Annual testing of TSH after stabilising
(Liothyronine (T3)?)

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How is hypothyroidism treated if they present with ischaemic heart disease?

Start at a lower dose 25mcg
Increase slowly
(risk angina)

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Which factors require special treatment if the patient is hypothyroid?

Ischaemic heart disease
Pregnancy
Postpartum thyroiditis
Myxedema coma

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How is hypothyroidism treated if they present with pregnancy?

Increase in LT4 dose

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How is hypothyroidism treated if they present with postpartum thyroiditis?

Trial withdrawal and measure TFTs in 6 weeks

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How is hypothyroidism treated if they present with myxedema coma?

May need IV T3

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When is treatment considered in subclinical hypothyroidism?

TSH > 10
TSH > 5 with +ve thyroid antibodies
TSH elevated with symptoms
When the patient is considering pregnancy/pregnant

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What are the risks of overtreatment of subclinical hypothyroidism?

Osteopenia

Atrial fibrillation

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What is the line of therapy for subclinical hypothyroidism?

Trial therapy 3-4months | Continue if symptomatic improvement

Inadequate hypothyroid treatment during pregnancy is associated with what?

Foetal loss | Lower IQ

How is hypothyroid treatment different in pregnancy?

Increased LT4 by 25% and monitor closely Keep TSH in low normal range Keep FT4 in high normal range Treat subclinical hypothyroidism if planning pregnancy

What are the causes of goitre?

``` Physiological: Puberty, pregnancy Autoimmune: Graves', Hashimotos Thyroiditis (acute or chronic) Iodine deficiency Dyshormonogenesis Giotrogens ```

What are the types of goitre?

``` Tumour Cyst Sarcoid, TB Diffuse (colloid/simple) Multinodular ```

What is the risk associated with solitary nodule thyroid?

Risk malignancy: <30 or >60, child Previous H&N radiation Cervical lymphadenopathy

How is a solitary nodule thyroid investigated?

Thyroid function test Ultrasound FINE NEEDLE ASPIRATION Isotope scanning if low TSH

What is a hot/cold nodule?

Cold: Nodule of thyroid which isnt functioning Hot: Nodule of thyroid which functions

What are the different types of thyroid cancer?

``` Papillary Follicular Anaplastic Lymphoma Medullary ```

What is papillary thyroid cancer?

Common Muiltifocal lesions Local lymphatic spread Good prognosis

What is follicular thyroid cancer?

Usually single lesion Metastases to lung/bone Good prognosis if resectable

Thyroid cancer has poor prognosis when?

<16, >45 Spread outside thyroid capsule TNM stage

How is thyroid cancer treated?

Near total thyroidectomy Ablative high dose radioiodine Long term suppressive doses of thyroxine THYROGLOBULIN

What is anaplastic thyroid cancer?

<5% Aggressive, local invasion Very poor prognosis External RT

What is thyroid lymphoma?

Rare ?Preexisting hashimotos thyroiditis External RT and chemo

What is medullary thyroid cancer?

Tumour of Parafollicular C-cells | Elevated serum calcitonin

What is the treatment for medullary thyroid cancer?

Total thyroidectomy

Medullary thyroid cancer is associated with what?

MEN 2 Phaeochromocytoma Hyperparathyroidism

What are the primary causes of thyrotoxicosis?

Grave's disease Toxic multinodular goitre Toxic adenoma

What are the secondary causes of thyrotoxicosis?

Pituitary adenoma secreting TSH

What are the causes of thyrotoxicosis without hyperthyroidism?

Destructive thyroiditis Amiodarone Excessive thyroxine

What is the biggest cause of hyperthyroidism?

Grave's disease - 70-80%

What is the prevalence of Grave's disease?

2-3:1000 2% female 0.16% male

What is the cause of Grave's disease?

Autoimmune - Thyroid peroxidase antibodies - TSH receptor antibodies - Review FH for autoimmune disease

What are the symptoms of Graves' disease?

``` Hyperthyroidism Eye bulging Clubbing Gynaecomastia Goitre Pretibial myxedema ```

How is thyrotoxicosis disease diagnosed?

``` Hyperthyroidism symptoms Thyroid antibodies (TSH receptor) ```

What is multi-nodular goitre?

Most common cause of thyrotoxicosis in the elderly Goitre in absense of Grave's disease WIll not go into spontaneous remission

Most common cause of thyrotoxicosis in the elderly?

Multi-nodular goitre

How does Subacute (de Quervain's) thyroiditis usually present?

``` <50y/o Viral trigger Painful goitre +/- fever/myalgia ESR raised 3-6 weeks thyrotoxicosis 3-6 months hypothyroidism ```

How is Subacute (de Quervain's) thyroiditis treated?

Short term steroid | NSAIDs

What are the most common treatments for thyrotoxicosis?

Surgery Radiation Antithyroid drugs Beta blockers (symptoms)

What drugs are used to treat hyperthyroidism?

Carbimazole Propylthiouracil (Titrate or replacement)

What are the side effects of antithyroid drugs?

Hypothyroidism (30%) Rash Agranulocytosis

Which patients are best suited for antithyroid drugs?

Elderly Cardiac complications Unwilling to have radioiodine

What are the two forms of radioiodine therapy for hypothyroidism?

High dose ablative: (90% cure, 70% hypothyroid) Variable/calculated: (60-90% cure, less hypo)

When is radioiodine avoided?

Severe eye disease

What is subclinical hyperthyroidism?

Suppressed TSH | Normal free thyroid hormones

What concerns are associated with subclinical hyperthyroidism?

Postmenopausal reduced bone density | 3x risk AF over 60s

When is treatment considered for subclinical hyperthyroidism?

Antithyroid/RAI In elderly Increased cardiac risk

Which drug can cause destructive thyroiditis?

Amiodarone

What are the symptoms of agranulocytosis?

Sudden onset: Sore throat Fever Rigors

What must radioiodine patients be aware of?

Pls dnt get preggers | Don't go near children for 2-3 weeks