Clinical thyroid disease - First half

Question 1

What are the main thyroid disorders?

Answer 1

Hypothyroidism

Hyperthyroidism

Goitre

Thyroid cancer

Question 2

Identify the labels on the diagram below

Answer 2

Question 3

What are the symptoms of hypothyroidism?

Answer 3

Hypothyroidism:

• Weight gain
• Lethargy
• Feeling cold
• Constipation
• Dry skin/hair, hair loss
• Heavy periods

Question 4

What are the signs of hypothyroidism?

Answer 4

Dry skin/hair

Goitre

Bradycardia

Slow reflexes

Puffy face

Question 5

How does severe hypothyroidism present?

Answer 5

Normal symptoms and…

puffy face

large tongue

hoarseness

coma

Question 6

What are the symptoms of Hyperthyroidism?

Answer 6

Hyperthyroidism:

• Weight loss
• Anxiety/irritability
• Heat intolerance
• Light periods
• Thyroid eye symptoms

Question 7

What are the signs of hyperthyroidism?

Answer 7

Sweaty palms

Palipitations

Hyperreflexia/Tremors

Goitre

Thyroid eye symptoms/signs

Question 8

What are the clinical types of hypothyroidism and their differences?

Answer 8

Primary (Thyroid):

• Raised TSH, Low FT4 & FT3

Subclinical (compensated):

• Raised TSH: Normal FT4 & FT3

Secondary (Pituitary):

• Low TSH, Low FT4 & FT3

Question 9

How common is hypothyroidism?

Answer 9

Commonest endocrine condition after diabetes

1/50 women get it

1/1000 men get it (very rare in men)

Subclinical hypothyroidism quite common in women over 60 (10%)

Question 10

What are the congenital causes of hypothyroidism?

Answer 10

Developmental:

• Agenesis / maldevelopment

Dysmorphogenesis:

• genetic defects for synthesis of thyroid hormone

Question 11

How common are congenital causes of hypothyroidism?

Answer 11

1 in 3500 births

• All babies screened in the UK

Question 12

What are the acquired types of primary hypothyroidism?

Answer 12

Autoimmune:

• Atrophic - most common
• Hashimoto’s thyroiditis

Iatrogenic:

• Postoperative / post- radioactive iodine
• Radiotherapy for head/neck cancers
• Antithyroid drugs, Amiodarone, Lithium, Interferon

Chronic iodine deficiency

Post-partum

Question 13

What are the causes of secondary hypothyroidism?

Answer 13

Pituitary or hypothalamic damage:

• Pituitary tumour
• Craniopharyngioma - _{Benign brain tumour begings near the pituitary}
• Post pituitary surgery or post radiotherapy

Question 14

How do you investigate hypothyroidism?

Answer 14

Serum TSH _{- High TSH confirms primary hypothyroidism}

Serum FT_{4 - Free thyroxine.}

Abnormalities of levels of TSH & FT₄ - used to determine which type of hypothyroidism

Autoantibodies - TPO (thyroid peroxidase antibodies)

Question 15

How is hypothyroidism treated?

Answer 15

Levothyroxine _{- for life, very little side effects. 50 - 150 ug.}

Other:

• Liothyronine (T₃ replacement)

Question 16

Describe the doses n shit for levothyroxine

Answer 16

Initial dose Levothyroxine 1.6 ug/kg for adults <65 years old

In practice:

• 100 ug for young and fit
• 50 ug for old and small

Dosage then increased until suffice

Question 17

How is hypothyroidism treated in those with ischaemic heart disease?

Answer 17

Start at lower dose 25 ug and increase cautiously; risk of precipitating angina

Question 18

How is postpartum thyroiditis treated?

Answer 18

Trial withdrawal and measure TFT’s in 6 weeks

(normally self-limiting)

Question 19

If a patient has is in a myxedemic coma

How are they treated for their hypothyroidism?

Answer 19

Very rare emergency, may need IV T3 (steroid)

Question 20

A patients thyroid hormone tests have come back showing raised TSH but normal levels of FT₃ and FT₄

Describe their investigation and management

Answer 20

Repeat thyroid hormone tests after 2-3 months and also test TPO antibodies

If TSH > 10 - treatment

If TSH > 5 and they are symptomatic - trial therapy

If pregnant/planning to be pregnant - treat

Question 21

What is the risk of overtreatment with subclinical hypothyroidism?

Answer 21

Osteopenia (pre-osteoporosis)

Atrial fibrillation

Basically just too much thyroid is bad innit

Question 22

Describe the management plan for someone with hypothyroidism during pregnancy?

Answer 22

Increased levothyroxine requirements during pregnancy

Specific management:

• Increase Levothyroxine dosage by 25%
  
  • Monitor closely
• Aim to keep TSH in low normal range (<2.5mU/l) and FT4 in high normal range

Treat subclinical hypothyroidism if planning/pregnant

Question 23

Why is important to manage hypothyroidism tightly in pregnancy?

Answer 23

Inadequately treated hypothyroidism linked with increased foetal loss and Lower IQ

Question 24

What is Goitre?

Answer 24

Swelling of the neck resulting from some form of enlargement of the thyroid gland

Question 25

What are the types of goitre shape?

Answer 25

**Nodular**: * Multinodular goitre * Solitary thyroid nodule (*solitary nodular goitre)* **Diffuse** **Tumour** **Miscellaneous**

Question 26

What are the causes of diffuse goitre? (obviously different causes may produce slightly different looking diffuse goitre to this)

Answer 26

**Puberty & pregnancy** - this is called **simple goitre** **Autoimmune thyroid disease** **Acute thyroiditis** (de Quervain's thyroiditis) Iodine deficiency (endemic goitre) Dyshormonogenesis Goitrogens

Question 27

What autoimmune conditions can cause diffuse goitre?

Answer 27

Graves' disease (thyrotoxicosis) Hashimoto's disease

Question 28

Solitary thyroid nodules may be due to tumours What are risk factors for a patient with a solitary thyroid nodule having a tumour?

Answer 28

–Child –Adults less than 30 or over 60 years –Previous head and neck irradiation –Pain, cervical lymphadenopathy

Question 29

What investigations should be done on a solitary thyroid nodule?

Answer 29

**Thyroid function tests** (T3,4, TSH) **Ultrasound** **FNA**

Question 30

What are the main types of thyroid malignancy? For each type, what is their: a) frequency b) spreading behaviour c) prognosis

Answer 30

Papillary (carcinoma): * most common type (70%), esp. in young people * Multifocal, local spreading to lymph nodes * Good prognosis Follicular (carcinoma): * 20% of cases, more common in females * Metastasises to lung/bone * Good prognosis if resectable Other: * Medullary cell * Anaplastic * Lymphoma

Question 31

How is thyroid cancer managed?

Answer 31

1) - Primary treatment option is **surgical**: * Total or near-total thyroidectomy 2) - High dose radio-iodine post-operative 3) - Levothyroxine - long term suppressive doses to stop recurrence Followups: * Monitor serum **thyroglobulin** as a tumour marker * Whole body iodine scanning (following 2-4 weeks of thyroxine withdrawal or recombinant TSH injections)

Question 32

For **anaplastic** thyroid cancer, describe the following: a) behaviour and spreading b) prognosis

Answer 32

**Anaplastic:** a) - Aggressive and locally invasive b) - Very poor prognosis

Question 33

For thyroid lymphoma, answer the following. a) Frequency and specific risk factors/causes b) Management

Answer 33

a) Rare - may arise from preexisting Hashimoto's disease b) Radiotherapy and chemotherapy

Question 34

What is medullary cell thyroid cancer?

Answer 34

Carcinomas that arise from parafollicular (C-cells) cells They are quite rare, but is often associated with MEN 2 - phaeochromocytoma & hyperparathyroidism They cause serum calcitonin levels to be raised