Thyroid Disease; A Surgical Perspective Flashcards
What type of thyroid cancer is heavily associated with Multiple Endocrine Neoplasia (MEN) syndrome
Medullary carcinoma
What does the word “thyros” mean
Shield
What does a fracture hyoid bone suggest to a medical examiner?
Must rule out strangulation
- however this is not pathognomonic
What branch of the vagus nerve is involved in phonation (ability to talk)
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
What is the foramen cecum?
Posterior aspect of the tongue is born from the same embryonic tissue as the thyroid
What are the 4 most significant complications during total thyroidectomy?
Hypoicalcemia
Hoarseness (damage to recurrent nerves)
Loss of airway
Internal bleeding
Theodore kocher
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
Where do the recurrent laryngeal nerves on both sides wrap around
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
Why is the thyrocervical trunk important in thyroid disease?
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
Thyroidae ima artery
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
Why is the anterior scalene muscle important to the thyroid anatomy
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.
What is an accessory thyroid gland
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
What does the sistrunk procedure do?
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
Middle thyroid vein and lymphatic drainage
Helps drain venous blood from thyroid gland
there is no thyroid artery however
Drainage of the thyroid lymphatic is via central -> lateral drainage
What is a. Virchow node?
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
Most common malignancies of the thyroid gland
1 is papillary carcinoma
these are also in order of least dangerous-> most dangerous
What surgical technique is contraindicated in anaplastic thyroid malignancies
Tracheotomy
- it increases therapeutic of metastasis
Zuckerkandl tubercle
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
Ligament of berry
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
What dr. Sandstorm and Richard Owen known for in medicine?
The discovering of the parathyroid glands on the thyroid gland
MEN syndromes
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
What is the biological marker used to follow medullary thyroid carcinoma progression and treatment
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
Is nuclear scanning or needle aspiration more commonly used in suspected thyroid nodules
Needle aspiration is quicker
Why is iodide therapy used in patients who need a CT/IV scan for the neck but not specifically the thyroid?
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
What structure close tot he thyroid gland that if manipulated leads to hypotension and Brady cardia?
Carotid bodies
- this leads to increased vagal stimulation
Why are cricothyroidotomies proffered to be done with vertical incision
Vertical incisions to avoid anterior jugular veins
If a fine-needle aspiration of a thyroid nodule returns as “indeterminate” what are the two most likely results?
Follicular adenoma or carcinoma
What develops from the primitive 3rd and 4th pharyngeal arches
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
Which of the following muscles are considered “strap” muscles
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
Difference between fine needle aspiration vs core biopsy
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
Lesions to the internal and external laryngeal nerves do what?
**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)
What is a thyroglossal duct cyst
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
Difference between hot and cold nodules on a thyroid scan
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
