Thyroid & Parathyroid Flashcards Preview

ABSITE 2019 > Thyroid & Parathyroid > Flashcards

Flashcards in Thyroid & Parathyroid Deck (29)
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1
Q

supplies both the inferior and superior parathyroids

A

Inferior thyroid artery (off thyrocervical trunk)

Ligate close to thyroid to avoid injury to parathyroid glands with thyroidectomy

2
Q

Mechanism of TSH

A

Released from anterior pituitary actso n thyroid to release T3/T4 via increased cAMP

3
Q

Blood supply to thyroid

A

Superior thyroid artery (1st branch off external carotid a)

4
Q

Accessory blood supply to isthmus in 1% of population

A

Ima artery

5
Q

Venous drainage of thyroid

A

Superior/Middle thyroid v: drain into IJ

Inferior thyroid v: drain into innominate v

6
Q

Injury resulting in loss of projection and easy voice fatigability

A

Superior largyneal nerve

7
Q

Supplies motor to the cricothyroid muscles

A

superior laryngeal n

8
Q

MC injured n during thyroidectomy

A

superior laryngeal n

9
Q

Supplies motor to all larynx except cricothyroid

A

recurrent laryngeal n

10
Q

Anatomy of superior vs recurrent laryngeal n

A

superior: runs lateral to thyroid lobes
recurrent: runs posterior to thyroid lobes in tracheoesophageal groove, left loops around aorta, right loops around innominate

11
Q

Injury resulting in hoarsness or airway obstruction

A

rucurrent laryngeal

12
Q

posterior medial suspensory ligament close to recurrent laryngeal nerves requiring careful dissection

A

ligament of berry

13
Q

Plasma T4:T3 ratio

A

15:1 (T3 is more active form)

14
Q

T3 production

A

produced in periphery from T4 to T3 conversion by deiodinases (seperate iodine from tyrosine)

15
Q

Most common cause of death in thyroid storm

A

high output cardiac failure

16
Q

When does thyroid storm occur

A

after surgery in Graves patient

17
Q

Treatment of thyroid storm

A

beta-blockers, Lugol’s solution (KI), cooling blankets, oxygen, glucose

18
Q

How does Lugol’s solution (KI) work to treat thyroid storm

A

Wolff-Chaikoff effect - high dose of iodine inhibits TSH action on thyroid, inhibits coupling of iodine results in less T3/T4

19
Q

FNA: follicular cells

A

lobectomy

20
Q

FNA: cyst fluid

A

drain fluid (unless bloody or recurrent then lobectomy)

21
Q

FNA: colloid tissue

A

most likely goiter

Tx w/ thyroxine, lobectomy if enlarging

22
Q

FNA: normal thyroid tissue + elevated thyroid function tests

A

solitary toxic nodule

Tx w/ methimazole, iodine if symptomatic

23
Q

Indeterminant FNA

A

get radionuclide study,
If Hot: methimazole, iodine
If Cold: lobectomy

24
Q

Dysphagia, dyspnea, dysphonia

A

lingual thyroid (base of tongue) tx w/ thyroxine suppression and abolish w/ iodine (only thyroid tissue in most patients who have it

25
Q

Midline cervical mass between hyoid and thyroid isthmus that moves up w/ swallowing

A

thyroglossal duct cyst, at risk of infection/premalignant, needs to be resected w/ hyoid bone and thyroglossal duct cyst (Sistrunk procedure)

26
Q
  • Most common location of an ectopic superior parathyroid gland:
A

tracheoesophageal groove

27
Q
  • Most common location of an ectopic inferior parathyroid gland:
A

thyrothymic ligament (ie, the thymus)

28
Q
  • Most common location of a missed adenoma if re-operating:
A

tracheoesophageal groove (“missed” here refers to a reopertion or a scenario where you are the surgeon to whom some other surgeon is referring his or her patient after being unsuccessful)

29
Q
  • Most common location of a parathyroid gland if cannot find it:
A

normal anatomic position (ie, “continue exploration,” or, if you have meticulously searched, “closed and get a Sestamibi scan” [never do a sternotomy in this scenario!])
* Do not confuse “ectopic” with “missed”