Hypo and Hyperthyroidism

Question 1

What is hyperthyroidism

Answer 1

Due to excess T3 and T4

Question 2

Is hyperthyroidism usually caused by excess TSH

Answer 2

No, this is very rare

Question 3

What is the most common cause of hyperthyroidism

Answer 3

Graves’ disease

Question 4

What is thyrotoxicosis

Answer 4

Clinical syndrome resulting from the effect on the tissues due to circulating T3 and T4 - increased metabolic rate

Question 5

What three diseases usually result in hyperthyroidism

Answer 5

1. Graves’ thyroiditis
2. Functioning adenoma
3. Toxic nodular goitre

Question 6

What is strums ovarii

Answer 6

A rare tumour in which thyroid hormones are produced and released into the blood - leading to an excess

Question 7

Signs of Graves’ thyroiditis

Answer 7

1. Associated with diffuse goitre
2. Thyroid is enlarged, firm and red
3. Hyperplasia of acing epithelium
4. Reduction in colloid
5. Accumulation of lymphocytes in lymphoid follicle formation

Question 8

Why does the thyroid appear red in Graves’ thyroiditis

Answer 8

Due to increased vascularisation

Question 9

How does Graves’ thyroiditis occur

Answer 9

IgG are produced (autoimmune) which bind to thyroid epithelial cells and stimulates it like TSH would - stimulatory hypersensitivity

Question 10

What are the IgG autoantibodies known as

Answer 10

LATS - Long-acting thyroid hypersensitivity

Question 11

Symptoms of individuals with Graves’ thyroiditis

Answer 11

1. Exopthalmos (bulging of eyes due to deposition of fat in retrobulbal area + inflammatio/oedema of extra-ocular muscles) - MOST COMMON
2. Accumulation of mucopolysaccharides in dermis
3. Finger clubbing

Question 12

Do adipocytes have receptors to TSH

Answer 12

Yes

Question 13

What is nodular goitre

Answer 13

Thyroid enlarges (usually due to iodine deficiency)

Question 14

How does hypothyroidism effect the metabolic rate

Answer 14

Lowers it

Question 15

Symptoms of hypothyroidism

Answer 15

1. Accumulation of mucopolysaccharides in the face - myxoedema face

Question 16

How does hypothyroidism effect a newborn

Answer 16

1. Physical growth and mental development impaired - Cretinism

Question 17

Where is cretinism common

Answer 17

Areas where diet contains insufficient iodine for thyroid hormone synthesis

Question 18

What is the most common cause of hypothyroidism

Answer 18

Hashimoto’s thyroiditis

Question 19

Describe some iatrogenic causes of hypothyroidism

Answer 19

1. Removal of the thyroid surgically

2. Certain drugs causing it as a side-effect

Question 20

What is myxoedema

Answer 20

swelling of the skin and underlying tissues giving a waxy consistency

Question 21

What can happen to the thyroid later on in patients with hypothyroidism

Answer 21

Atrophy and fibrosis

Question 22

Appearance of the thyroid during hypothyroidism

Answer 22

1. Firm, fleshy and pale
2. Densley infiltrated by plasma cells and lymphocytes with lymphocytic colloid formation
3. reduction in colloids
4. Thyroid epithelial cells enlarge and develop eosinophilic granular cytoplasm

Question 23

Why do thyroid epithelial cells develop eosinophilic granular cytoplasms in hypothyroidism and what are they now known as

Answer 23

Due to proliferation of mitochondria

Askanazy cells

Question 24

Why is there a transient phase at the beginning of Hashimoto’s thyroiditis

Answer 24

1. Damage to the thyroid follicles lead to release of thyroglobulin into circulation

Question 25

What would appear in blood tests for patient's who are positive for Hashimoto's thyroiditis

Answer 25

1. Two autoantibodies One reacting with thyroid peroxidase One reacting with thyroglobulin

Question 26

Where are the autoantibodies in Hashimoto's thyroiditis formed

Answer 26

Locally by plasma cells infiltrating the thyroid

Question 27

Define goitre

Answer 27

Enlargemnt of the whole gland WITHOUT hyperthyroidism

Question 28

What is parenchyma's goitre

Answer 28

1. First hyperplasia of the thyroid epithelium 2. Loss of coloids 3. Eventually less active areas are compressed by hyperplastic areas 4. Fibrosis may separate the less active areas - multi nodular goitre

Question 29

How can multi-nodular goitre be detected

Answer 29

They can be palpated clinically

Question 30

What is colloid goitre

Answer 30

1. No epithelia hyperplasia (unlike parenchyma) 2. Lots of colloid found 3. Colloids form cysts 4. Haemorrhage found

Question 31

Symptoms of colloid goitre

Answer 31

1. Tracheal compression (difficulty breathing) | 2. Stridor

Question 32

What is stridor

Answer 32

Harsh or greeting sound during breathing

Question 33

How is hypothyroidism caused (3 ways)

Answer 33

1. Iodine deficiency 2. Inherited enzyme defects in T3 n T4 synthesis 3. Drugs that induce hypothyroidism

Question 34

Under a histological slide, what is an indication of colloid goitre

Answer 34

The follicles are distended by accumulated colloid

Question 35

How do we deal with people who come into a clinic with a solitary mass in the thyroid (this is very common)

Answer 35

1. Checking thyroid secretory status (serum TSH, T3 and T4 levels) 2. Ultrasound imaging and checking for thyroid neoplasia \\

Question 36

What two ways do solitary masses tend to go

Answer 36

1. Turn out to be one large nodule in a multi nodular goitre | 2. May be neoplastic (rare)

Question 37

What is the most common thyroid tumour

Answer 37

Follicular adenoma

Question 38

Signs of follicular adenoma

Answer 38

1, Solid mass within a fibrous capsule, compressing the adjacent gland 2. Centre shows haemorrhage and cystic changes

Question 39

Histological signs of follicular adenoma

Answer 39

1. Compact follicles lined by epithelium 2. Nuclear hyperchromatism 3. Very little colloid 4. Fibrous capsule not breached by tumour 5. Epithelial cells have large central clear areas in nuclei

Question 40

How common is a follicular carcinoma

Answer 40

Rare

Question 41

Why is a follicular carcinoma rare

Answer 41

Because tumours are well-differentiated

Question 42

What is follicular carcinoma associated with

Answer 42

Exposure to ration (x-rays)

Question 43

In what aged patients is papillary adenocarcinoma found

Answer 43

Less than 45s

Question 44

Appearance of a papillary adenocarcinoma

Answer 44

1. Non-encapsulated infiltrative mass 2. Firm - due to fibrosis 3. White - due to fibrosis

Question 45

What do papillary adenocarcinomas look like histologically

Answer 45

1. Epithelial papillary projections between which calcified capsules (psammoma bodies) are present 2. Nulcei have clear central areas

Question 46

How do papillary adenocarcinomas metastasise

Answer 46

Via the lymphatic within the thyroid glands and the cervical lymph nodes

Question 47

Why does papillary adenocarcinoma have a good prognosis

Answer 47

As it is a slow-growing tumour

Question 48

Follicular adenocarcinoma vs follicular adenoma

Answer 48

1. Adenocarcinoma shows blood vessels and invasion of capsule

Question 49

How does follicular adenocarcinoma metastasise

Answer 49

Blood stream to the bones and lungs

Question 50

Why does follicular adenocarcinoma have a good prognosis

Answer 50

Retains ability to take up 131-I

Question 51

Where are anapaestic carcinomas common

Answer 51

Elderly

Question 52

Why does anapalastic carcinomas have a poor prognosis

Answer 52

Because it results in rapid local invasion of structures such as the trachea

Question 53

What causes medullary carcinoma

Answer 53

Thyroid C-cells

Question 54

What do C-cells produce

Answer 54

Calcitonin

Question 55

Role of calcitonin

Answer 55

Lowers Ca levels in the blood: 1. Inhibits osteoclast activity in bones 2. Inhibits renal tubular absorption of Ca and phosphate

Question 56

What acts antagonistically to calcitonin

Answer 56

Vitamin D and PTH

Question 57

How does non-hodgkin's lymphoma relate to thyroid

Answer 57

Originates in the thyroid in Hashimoto's thyroiditis more commonly

Question 58

Where do lymphomas of the thyroid gland originate from

Answer 58

Neoplasms of mucosa-associated lymphoid tissue