T1 L8 Thyroid disease: hyper, hypo and other

Question 1

What is hypothyroidism?

Answer 1

Underproduction of thyroid hormone

Question 2

What is hyperthyroidism?

Answer 2

Overproduction of thyroid hormone

Question 3

What is thyrotoxicosis?

Answer 3

Overproduction of thyroid hormone (hyperthyroidism)

Question 4

What is euthyroid?

Answer 4

Normal production of thyroid hormone

Question 5

What is a goitre?

Answer 5

Enlargement of the thyroid gland

Question 6

How to examine the thyroid?

Answer 6

Feel for thyroid cartilage then move down and lateral
Moves on swallowing
Listen for bruit 
Retrosternal extension 
Check cervical lymph node system

Question 7

What are the normal ranges for a thyroid function test?

Answer 7

TSH: 0.3-4.2mu/l
FT4: 12-22pmol/l
FT3: 3.1-6.8pmol/l

Question 8

Why doesn’t a negative autoantibody result exclude autoimmune disease?

Answer 8

May have different antibodies that aren’t tested for

Presence only helps to confirm a diagnosis

Question 9

What are the different types of thyroid autoantibodies?

Answer 9

Destructive

Stimulatory

Question 10

What is a destructive thyroid autoantibody?

Answer 10

Target thyroid for autoimmune destruction

Question 11

What is a stimulatory thyroid autoantibody?

Answer 11

Stimulates TSH receptor

Question 12

What are the symptoms of hypothyroidism?

Answer 12

Lethargy
Weight gain
Cold intolerance
Constipation
Facial puffiness
Dry skin
Hair loss
Hoarseness
Heavy menstrual periods

Question 13

What are the signs of severe hypothyroidism?

Answer 13

Change in appearance 
Periorbital oedema
Dry, flaking skin
Diffuse hair loss
Bradycardia
Signs of median nerve compression
Effusions
Delayed relaxation of reflexes
Croaky voice
Goitre
Stupor or coma

Question 14

What are the causes of primary hypothyroidism?

Answer 14

Autoimmune hypothyroidism 
Hypothyroidism after treatment for hyperthyroidism
Thyroiditis
Drugs
Congenital hypothyroidism
Iodine deficiency

Question 15

What are the clinical results for primary hypothyroidism?

Answer 15

Increased TSH
Decreased T4
Decreased T3

Question 16

What are the causes of secondary hypothyroidism?

Answer 16

Diseases of hypothalamus or pituitary

Question 17

What are the clinical results for secondary hypothyroidism?

Answer 17

Decreased TSH
Decreased T4
Decreased T3

Question 18

Describe autoimmune hypothyroidism

Answer 18

Chronic autoimmune thyroiditis: Hashimoto’s

Myxoedema

Question 19

What is myxoedema?

Answer 19

Accumulation of glycosaminoglycans in interstitial spaces of tissue

Question 20

What are the symptoms of hyperthyroidism?

Answer 20

Weight loss
Lack of energy
Heat intolerance
Anxiety / irritability
Increased sweating
Increased appetite
Thirst 
Palpitations
Pruritus
Weight gain
Loose bowels
Oligomenorrhoea

Question 21

What are the signs of hyperthyroidism?

Answer 21

Tremor
Warm, moist skin
Sinus tachycardia
Atrial fibrillation
Brisk reflexes
Eye signs
Thyroid bruit
Muscle weakness
Atrial fibrillation

Question 22

What are the eye signs of hyperthyroidism?

Answer 22

Lid retraction
Proptosis
Ophthalmoplegia
Inflammation of conjunctiva

Question 23

What are the causes of hyperthyroidism?

Answer 23

Autoimmune hyperthyroidism
Toxic multimodule goitre
Toxic adenoma
Thyroiditis
Drugs e.g. amiodarone

Question 24

Why does gestational thyrotoxicosis occur?

Answer 24

Placental HCG is structurally similar to TSH

More common if hyperemesis / twin pregnancy

Question 25

What is thyroid eye disease?

Answer 25

Inflammation of all orbital tissues except the eye

Question 26

What are some mild symptoms of thyroid eye disease?

Answer 26

Itchy / dry eyes | Prominent eyes / change in appearance / proptosis

Question 27

What are some more severe symptoms of thyroid eye disease?

Answer 27

``` Diplopia / loss of sight Loss of colour vision Redness / swelling of conjunctiva Unable to fully close eye Ache / pain / tightness behind eye ```

Question 28

What is the active treatment for thyroid eye disease?

Answer 28

Encourage smoking cessation Steroids Immunosuppressive / steroid-sparing agents Radiotherapy

Question 29

What are the surgical treatments for thyroid eye disease?

Answer 29

Orbital decompression | Eyelid surgery

Question 30

What is thyroid eye disease associated with in 20%?

Answer 30

Graves disease

Question 31

What increases the likelihood of Graves disease?

Answer 31

Personal or family history of autoimmune thyroid / endocrine disease Goitre with a bruit Thyroid eye disease Positive thyroid autoantibody titre

Question 32

Describe the thyroid function test results in hyperthyroidism

Answer 32

Low TSH Raised FT4 Raised FT3 TSH-receptor autoantibodies (Graves disease)

Question 33

What further investigations may be done in hyperthyroidism?

Answer 33

Thyroid autoantibodies | Thyroid uptake scan

Question 34

What is the medical treatment for Graves disease?

Answer 34

``` Carbimazole or propylthiouracil 18 to 24 months Titrate or block replace 1/3 have long term cure rate 2/3 will relapse ```

Question 35

What are the risks of surgical treatment for Graves disease?

Answer 35

``` Anaesthetic Neck scar Hypothyroidism Hypoparathyroidism Vocal cord palsy due to recurrent laryngeal nerve damage ```

Question 36

What are the risks if no treatment is given for Graves disease?

Answer 36

Symptoms worsen Atrial fibrillation - stroke Osteoporosis - fractures

Question 37

What is a thyrotoxic crisis (thyroid storm)?

Answer 37

Associated with under or over treated hyperthyroidism | Heart rate, BP, temperature soar to extreme levels

Question 38

What increases the likelihood of a thyrotoxic crisis?

Answer 38

``` Incompletely treated hyperthyroidism Start-stop Erratic compliance Early on in course of treatment Surgery / radioiodine treatment without adequate preparation ```

Question 39

What triggers a thyrotoxic crisis?

Answer 39

Surgery Childbirth Acute severe illness: infection, trauma, diabetic ketoacidosis, stroke, PE

Question 40

What is thyroiditis?

Answer 40

Self-limiting thyroid disease Transient mild thyrotoxicosis Resolves in 1-2 months Give beta blockers if required Longer hypothyroid phase Last 4-6 months May require thyroxine treatment for a while

Question 41

When should thyroiditis be considered?

Answer 41

If patient is pregnant or 1 year postpartum Diabetes, family history of thyroid disease, smoker Tender thyroid Clinical thyroid status doesn't fit with lab results No diagnostic features of Graves disease Current / recent treatment with immunomodulatory medication

Question 42

What other diseases are associated with thyroid disease?

Answer 42

``` Type I diabetes Pernicious anaemia Coeliac disease Premature ovarian failure Addison's disease Turner syndrome Down's syndrome Medications: lithium, amiodarone ```