Thyroid Disease

Question 1

Give the two ways that a thyroid can be enlarged

Answer 1

Symmetrically enlarged (goitre) or assymetrically enlarged (solitary nodule

Question 2

Give a differential diagnosis for neck swellings/masses

Answer 2

Thyroid enlargement
Lymphadenopathy
Thyroglossal duct cyst
Salivary gland enlargement
Branchial arch anomal
Cystic hygroma
Pharyngeal pouch
Carotid body tumor

Question 3

Name the 4 main causes of a goitre (symmetrical thyroid enlargement)

Answer 3

Physiological
Simple/non-nodular
Multinodular
Thyroiditis

Question 4

What is a physiological goitre?

Answer 4

This is when the thyroid is enlarged due to a normal physiological process. It occurs often during puberty, pregnancy and lactation.

Question 5

What are the clinical findings in a physiological goitre?

Answer 5

The gland is soft, diffusely enlarge, visible and palpable.

Question 6

What is the management of a physiological goitre?

Answer 6

Reassurance. No medication is needed.

Question 7

What is a simple/non-nodular goitre?

Answer 7

This occurs in areas where iodine is in low concentrations in water or salt is not iodinated.

Question 8

What is the most common cause of a goitre?

Answer 8

Multinodular goitre

Question 9

What is a multinodular goitre?

Answer 9

The thyroid gland is enlarged due to multiple adenomatous and colloid nodules with occasional cystic degeneration

Question 10

What is the pathophysiology of a multinodular goitre?

Answer 10

Enlargement is due to longstanding stimulation of the thyroid by TSH during periods of suboptimal thyroid hormone production. Initially, there is diffuse enlargement and the gland goes through cyclical changes of hyperplasia and colloid formation to eventual multinodularity.

Question 11

Name 4 drugs that are goitrogens (could cause a goitre)

Answer 11

Anti-thyroid drugs
Sulphonylureas
Iodine-containing medication
Cobalt

Question 12

What is thyroiditis?

Answer 12

Inflammation of the thyroid gland

Question 13

What are the clinical findings in thyroiditis?

Answer 13

Diffuse thyromegaly which may be firm or multinodular.

Question 14

What is the most common thyroiditis?

Answer 14

Autoimmune Hashimoto’s thyroiditis

Question 15

How does de Quervain’s thyroiditis present?

Answer 15

Pain and tenderness as well as fever, sore throat and dysphagia along with the other features of thyroiditis - thyromegaly.

Question 16

What investigations are done to confirm thyroiditis?

Answer 16

Antibody serology
Aspiration cytology

Question 17

What is the treatment for thyroiditis?

Answer 17

Steroids and aspirin.

Question 18

What are causes of a solitary thyroid nodule?

Answer 18

Hyperplastic/adenomatous nodule (most common
Simple cyst
Follicular adenoma
Thyroid carcinoma

Question 19

What investigations are done for nodular thyromegaly?

Answer 19

Ultrasound
Aspiration cytology
Radio-isotope scanning
CT scans
Blood tests

Question 20

What is the imaging modality of choice for the thyroid?

Answer 20

Ultrasound. It can confirm a nodule vs multinodular thyroid, whether it is solid or cystic and other features associated with malignancy

Question 21

What features of malignancy may be seen on ultrasound?

Answer 21

Hypoechogenicity
Increased vascularity
Local lymphadenopathy
Microcalcifications

Question 22

Which classification system is used for thyroid cytopathology?

Answer 22

Bethesda
Note - a score of 3 or more warrants concern

Question 23

When is radio-isotope scanning done?

Answer 23

Usually only for thyrotoxic patients

Question 24

How are radio-isotope scans interpreted? (Hot vs cold spots)

Answer 24

Solid nodules are “cold” while hyperfunctioning nodules are “hot” and almost always benign. The cold nodules require further investigation.

Question 25

What are CT scans helpful for in thyroid disease?

Answer 25

Evaluation of retrosternal goitre extension and airway compression

Question 26

Which blood tests should be ordered in thyroid disease investigations?

Answer 26

TSH T4/T3 Serum thyroid antibodies

Question 27

What are the indications for surgery for a solitary thyroid nodule?

Answer 27

Suspicious nodule on USS Cytology which shows malignancy, is suspicious or indeterminate A cyst that refills after aspiration

Question 28

What are the options for surgery for a solitary nodule? (Partial vs total thyroidectomy etc.)

Answer 28

A lobectomy of the affected side is first performed. If it is benign, nothing further is done. However, in general, if it is malignant a total thyroidectomy is done.

Question 29

Which thyroid cancer does not need a total thyroidectomy?

Answer 29

<1 cm unifcoal papillary carcinoma. This can be treated with a lobectomy as it is usually well localized.

Question 30

What are the indications for surgery for a multinodular goitre?

Answer 30

Most cases of MNG are benign and reassurance is all that is needed. However, indications include: Compression symptoms - dysphagia, respiratory difficulty, retrosternal extension, or superior mediastinal syndrome) If it is very unsightly Any concern of malignancy

Question 31

What are the options for surgery for a MNG? (Partial vs total thyroidectomy etc.)

Answer 31

Total thyroidectomy with careful preservation of the parathyroid glands. If the MNG is unilateral, a lobectomy can be performed.

Question 32

Name 7 features suggestive of a malignant thyroid mass

Answer 32

Asymmetrical goitre or nodule in children or men Rapid onset Progressive size increase Local invasion Pain Lymphadenopathy Hoarseness

Question 33

What is the most common type of thyroid carcinoma?

Answer 33

Well differentiated thyroid carcinomas (WDTCs)

Question 34

Other than WDTCs, what thyroid carcinomas may occur?

Answer 34

In decreasing order of prevalence: Medullary Anaplastic Lymphoma Other rarer types

Question 35

What is the management of WDTC?

Answer 35

Surgical - total thyroidectomy Complementary radioactive iodine - to ablate any residual disease Endocrine therapy - thyroxin to suppress TSH and thus recurrence of disease

Question 36

What are the histological subtypes of WDTC? Outline common features of each.

Answer 36

Papillary (40%) - usually small, multifocal and LN spread common Follicular (30%) - larger, single nodule with haematogeneous spread, iodine sensitive Mixed (30%)

Question 37

Which cells are thought to be the precursors for medullary thyroid carcinoma?

Answer 37

Calcitonin producing C cells

Question 38

Which syndrome is medullary carcinoma a part of?

Answer 38

MEN 2

Question 39

What is the management of medullary carcinoma?

Answer 39

It is much more aggressive so a total thyroidectomy is indicated along with nodal dissection. This does not respond to iodine therapy

Question 40

What is anaplastic thyroid carcinoma?

Answer 40

Also called undifferentiated thyroid carcinoma. It is the least common and is usually irresectable and incurable at presentation.

Question 41

What is the most common cause of thyrotoxicosis?

Answer 41

Graves disease

Question 42

What is the pathophysiology of Graves disease?

Answer 42

Auto-immune response to TSH receptors. Antibodies to the receptor cause prolonged stimulation of the receptor and excessive thyroxin production.

Question 43

Other than Graves disease, what are other causes of thyrotoxicosis?

Answer 43

Toxic multinodular goitre Toxic solitary nodule Excess TSH (pituitary, paraneoplastic) Excess T4 (iatrogenic, paraneoplastic) Excess Iodine Thyroiditis Struma ovarii

Question 44

How is thyrotoxicosis diagnosed?

Answer 44

Clinical features and biochemical confirmation (Low TSH with high T4/T3)

Question 45

What is the management of thyrotoxicosis?

Answer 45

The primary treatment is medical. Surgery is only performed when specially indicated.

Question 46

What medicatios are prescribed for thyrotoxicosis?

Answer 46

Neomercazole Propanolol Radioactive iodine

Question 47

What are the indications for surgery in thyrotoxicosis?

Answer 47

Pregnancy After medical treatment fails If radioactive iodine is contraindicated Large, multinodular gland

Question 48

List complications of thyroidectomies

Answer 48

Recurrent laryngeal nerve damage Serious airway obstruction - oedema or haematoma Haemorrhage Tracheomalacia Hypocalcaemia Hypothyroidism