Thyroid

Question 1

What is the arterial supply to the thyroid?

Answer 1

• superior thyroid artery from the external carotid
• inferior thyroid off the thyrocervical trunk from the subclavian
• IMA from the right innominate to the isthmus

Question 2

What is the venous drainage of the thyroid?

Answer 2

• superior and middle thyroid to the IJ
• inferior thyroid to the innominate

Question 3

Which form of thyroid hormone is more active?

Answer 3

T3

Question 4

What embryologic structures give rise to the thyroid?

Answer 4

• thyroid tissue from the endoderm of the foramen caecum
• parafollicular c-cells from the 4th endodermal pouch

Question 5

How should a thyroglossal duct cyst be managed?

Answer 5

with resection given potential for infection and malignant transformation

Question 6

How is thyroid storm treated?

Answer 6

beta blockers, Lugol’s solution, cooling blankets

Question 7

What are concerning features of a thyroid nodule?

Answer 7

• hypoechoic
• microcalcifications
• irregular marings
• unorganized vascular patterns
• lymph-vascular invasion
• taller than wide

Question 8

How should the following thyroid nodule FNA results be managed:
- indeterminate
- benign
- AUS/FLUS
- follicular neoplasm
- suspicious malignancy
- malignancy

Answer 8

• indeterminate: repeat FNA
• benign: US in 6-12 months
• AUS/FLUS: repeat FNA
• follicular neoplasm: lobectomy
• suspicious malignancy: lobectomy
• malignancy: total thyroidectomy

Question 9

Which can be given in pregnancy, PTU or methimazole?

Answer 9

• PTU can be given during preganancy
• both have a risk of aplastic anemia/agranulocytosis

Question 10

How does Grave’s disease appear on RAI?

Answer 10

• mediated by TSH receptor antibodies
• diffuse uptake

Question 11

How is subacute granulomatous thyroiditis treated?

Answer 11

it is of viral etiology and treated with NSAIDs and steroids

Question 12

What is Hashimoto thyroiditis?

Answer 12

an autoimmune condition causing hypothyroidism due to antibodies against thyroid tissue

Question 13

Describe the etiology, pathology, spread, and treatment of papillary thyroid cancer.

Answer 13

• most common thyroid malignancy, more prevalent in women
• path with psammoma bodies and orphan Annie nuclei
• spread via lymphatics
• treated with total thyroidectomy with level VI involvement

Question 14

Why does follicular neoplasm on thyroid US prompt a lobectomy?

Answer 14

because FNA is unreliable at ruling out follicular thyroid cancer so excision biopsy is needed

Question 15

Describe the spread and treatment of follicular thyroid cancer.

Answer 15

• hematogenous spread
• treat with total thyroidectomy, MRND, and post-op RAIA

Question 16

Describe the etiology, mutation, treatment, and surveillance of medullary thyroid cancer.

Answer 16

• a cancer of parafollicular c-cells which normally produce calcitonin
• associated with RET mutation
• treat with total thyroidectomy and central neck dissection
• surveillance with CEA and calcitonin

Question 17

Which MEN patients get a prophylactic thyroidectomy?

Answer 17

• MEN2A and MEN2B patients
• by 5 years of age at the latest

Question 18

Which type of thyroid cancer does RAI ablation not work?

Answer 18

medullary because it is derived from parafollicular c-cells

Question 19

How is superior laryngeal nerve damage avoided during thyroid surgery?

Answer 19

ligation of the vessels close to thyroid tissue