Thyroid Disease; A Surgical Perspective

Question 1

What type of thyroid cancer is heavily associated with Multiple Endocrine Neoplasia (MEN) syndrome

Answer 1

Medullary carcinoma

Question 2

What does the word “thyros” mean

Answer 2

Shield

Question 3

What does a fracture hyoid bone suggest to a medical examiner?

Answer 3

Must rule out strangulation

- however this is not pathognomonic

Question 4

What branch of the vagus nerve is involved in phonation (ability to talk)

Answer 4

External branch of the superior laryngeal nerve
- innervates the cricothyroid muscle which moves vocal cords

**internal branch of superior laryngeal nerve innervates the mucosa of the epiglottis and sensation in taste

Question 5

What is the foramen cecum?

Answer 5

Posterior aspect of the tongue is born from the same embryonic tissue as the thyroid

Question 6

What are the 4 most significant complications during total thyroidectomy?

Answer 6

Hypoicalcemia

Hoarseness (damage to recurrent nerves)

Loss of airway

Internal bleeding

Question 7

Theodore kocher

Answer 7

One of the founding fathers of thyroid surgery all techniques

He has a kocher clamp named after him used commonly in surgery

Also has two incisions named after him

• right subcostal incision from the xyphoid process down to the medial aspect of the 10th rib made in gallbladder surgery
• transverse incision made in the neck to remove the thyroid gland

Also the kocher maneuver = moves duodenum to feel for the head of the pancreas. Also another subset maneuver is to reduce a discolored shoulder

a lot of his early patients developed creatism however

Question 8

Where do the recurrent laryngeal nerves on both sides wrap around

Answer 8

Right = wraps around right subclavian

Left = wraps around the aortic arch

• *Both of these nerves below come off the recurrent laryngeal nerves:
  1) Superior external nerve: stimulates the mucosa of the thyroid and sensation
  2) Superior internal nerve: stimulates the cricothyroid muscles

**both recurrent laryngeal nerves are found in the tracheal-esophageal groove on each side

Question 9

Why is the thyrocervical trunk important in thyroid disease?

Answer 9

It gives off the inferior thyroid artery which provides blood supply to all 4 parathyroid glands
- damage to this artery can cause severe hypocalcemia

Also supply’s the inferior thyroid so damage can result in minor hypothyroidism or exacerbation of already established hypothyroidism

Question 10

Thyroidae ima artery

Answer 10

A rare congenital abnormality where a artery comes directly off the aorta/brachiocephalic trunk and supply the majority of the thyroid blood supply

**must be careful before conducting a incision on the trachea inferior to the isthmus of the thyroid to look for this on imaging. Cutting this can result in severe bleeding into mediastinum and ischemia to thyroid

Question 11

Why is the anterior scalene muscle important to the thyroid anatomy

Answer 11

Is anatomically important on imaging and surgery since it divides the subclavian vein and the suprascapular artery into right and left halves.

The subclavian vein runs anterior to it whereas the subclavian artery runs posterior to the scalene, therefore if you can feel it on a very skinny person, you can use it as a landmark to known where to go to place a central line.

Question 12

What is an accessory thyroid gland

Answer 12

A portion of thyroid that is found somewhere along the pathway from where the primordial thyroid is to where the adult thyroid resides normally
- most common position is located near the root of the tongue

Nuclear scans will show if there are accessory tissues

These tissues are usually removed unless the normal thyroid tissue is not functional

Question 13

What does the sistrunk procedure do?

Answer 13

A surgical procedure that is used to deal with remnants of the thyroglossal duct
- especially thryoglossal cysts or the pyramidal lobe of the thyroid

It does require removing the middle of the hyoid bone however to conduct properly since without removal of this part of the hyoid bone, the cyst will reoccur

Question 14

Middle thyroid vein and lymphatic drainage

Answer 14

Helps drain venous blood from thyroid gland

there is no thyroid artery however

Drainage of the thyroid lymphatic is via central -> lateral drainage

Question 15

What is a. Virchow node?

Answer 15

An enlarged supraclavicular lymph node on the left side of the patient

• *Very commonly seen in metastatic breast in women or metastatic lung cancer in men
• can also mean GI malignancies in either sexes

Question 16

Most common malignancies of the thyroid gland

Answer 16

1 is papillary carcinoma

these are also in order of least dangerous-> most dangerous

Question 17

What surgical technique is contraindicated in anaplastic thyroid malignancies

Answer 17

Tracheotomy

- it increases therapeutic of metastasis

Question 18

Zuckerkandl tubercle

Answer 18

Posterior view of the trachea and esophagus will show these two tubercles that look like nodules coming off the thyroid

These are normal remnants of the posterior lobe of the thyroid glands

Question 19

Ligament of berry

Answer 19

The ligament that connects the thyroid gland to the trachea and esophagus
- needs to be cut to remove the thyroid gland

also a term called “berry picking” is used to mean removing or biopsy lymph nodes along berry’s ligament

Question 20

What dr. Sandstorm and Richard Owen known for in medicine?

Answer 20

The discovering of the parathyroid glands on the thyroid gland

Question 21

MEN syndromes

Answer 21

Are rare in general, however all three subtypes are heavily tied to parathyroid hyperplasia or medullary thyroid carcinoma

if a patient is diagnosed with medullary carcinoma of the thyroid you MUST screen their family and the patient for MEN 1 and 2 syndrome

MEN 1 (warmer syndrome) = 90% parathyroid hyperplasia, 70% to have medullary thyroid carcinoma

MEN 2 (supple syndrome) = 50% parathyroid hyperplasia; near 100% chance to have medullary thyroid carcinoma

Question 22

What is the biological marker used to follow medullary thyroid carcinoma progression and treatment

Answer 22

Calcitonin levels

This is because medullary carcinoma o the thyroid is generated via dysplastic follicular-C cells

patients always present with excess calcium in blood also

Question 23

Is nuclear scanning or needle aspiration more commonly used in suspected thyroid nodules

Answer 23

Needle aspiration is quicker

Question 24

Why is iodide therapy used in patients who need a CT/IV scan for the neck but not specifically the thyroid?

Answer 24

To prevent the thyroid from uptake as much radioactive material and causing damage

also remember that if you suspect cancer of the thyroid gland, you CANT give CT scans with IV contrast since treatment with radioactive iodine for thyroid issues is no longer a possibility for a good amount of time

Question 25

What structure close tot he thyroid gland that if manipulated leads to hypotension and Brady cardia?

Answer 25

Carotid bodies

- this leads to increased vagal stimulation

Question 26

Why are cricothyroidotomies proffered to be done with vertical incision

Answer 26

Vertical incisions to avoid anterior jugular veins

Question 27

If a fine-needle aspiration of a thyroid nodule returns as “indeterminate” what are the two most likely results?

Answer 27

Follicular adenoma or carcinoma

Question 28

What develops from the primitive 3rd and 4th pharyngeal arches

Answer 28

3rd:

• dorsal portion = inferior parathyroid glands
• ventral portion = thymus
• also generates hyoid bone
• associated cranial nerve = CN 9

4th:
- dorsal portion = superior parathyroid glands
- ventral portion = C-cells
- also generates cricothyroid, cricopharyngitis and both thyroid and cricoid cartilages
- associated cranial nerve = superior laryngeal branch of the vagus

6th arches shows the recurrent laryngeal branch of the vagus

Question 29

Which of the following muscles are considered “strap” muscles

Answer 29

Sternohyoid

Sternothyroid

Thyrohyoid

Omohyoid

all muscles are below the hyoid bone and function to elevate and depress the hyoid bone. Also moves larynx during swallowing and speech

Question 30

Difference between fine needle aspiration vs core biopsy

Answer 30

FNA:

• very thin needle
• pulls very small pieces of tissue out of tumors
• needs ultrasound if its the target is deep but requires no anesthesia and no skin cuts
• may not have enough tissue for definitive diagnosis

Core biopsy:

• larger needle
• requires local anaesthesia and skin cutting
• are always definitive

Question 31

Lesions to the internal and external laryngeal nerves do what?

Answer 31

**both come off the recurrent laryngeal nerve of the vagus nerve

Internal laryngeal nerve

• innervates mucus membranes above the vocal cords and taste buds on the epiglottis
• lesions result in loss of sensation ABOVE vocal cords and loss of posterior taste

External laryngeal nerve
- lesions result in paralysis of the cricothyroid muscles resulting in paralysis of vocal cords also (cant speak or extreme hoarseness)

Question 32

What is a thyroglossal duct cyst

Answer 32

Ectopic thyroid tissue that is attached to the hyoid bone
- are the most common congenital neck cyst

Will present as a palpable and moveable midline structure on the neck. Moves with swallowing as well and unless infected is painless. May appear red ANS swollen and painful if infected.

To remove it you must do the sistrunk procedure which requires removal of the cyst, the duct and middle portion of the hyoid bone as well as the pyramidal lobe of the thyroid if it exists

Question 33

Difference between hot and cold nodules on a thyroid scan

Answer 33

Hot nodule = overactive portion of the thyroid
- is usually benign but can be malignant

Cold nodule = underactive portion of the thyroid
- is assumed malignant until proven not

really thyroid scans are NOT done to determine thyroid cancer, only cause of hypothyroidism or hyperthyroidism