Fiser ABSITE Ch. 22 Thyroid Flashcards Preview

Surgery > Fiser ABSITE Ch. 22 Thyroid > Flashcards

Flashcards in Fiser ABSITE Ch. 22 Thyroid Deck (80)
Loading flashcards...
1
Q

What is the origin of the thyroid?

A

1st and 2nd pharyngeal pouches

2
Q

What is the blood supply of the thyroid with origins?

A

superior thyroid arter is the 1st branch off the external carotid artery; inferior thyroid artery is off the thyrocervical trunk

3
Q

What is the blood supply to the parathyroids and how should they be ligated in thyroidectomy?

A

inferior thyroid arteries, ligate close to thyroid to avoid injuring parathyroids

4
Q

What is the blood supply to the thyroid isthmus that is occurs in 1% and its origin?

A

Ima artery arises from the innominate or aorta

5
Q

What is the venous drainage of the thyroid and where do they drain?

A

Superior and middle thyroid veins drain into the internal jugular. The inferior vein drains to the innominate vien

6
Q

Nonrecurrent laryngeal nerve arises directly from the vagus and occurs in 2-3%. Which side is more common?

A

right

7
Q

The superior laryngeal nerve tracks close to what other structure?

A

superior thyroid artery but is variable

8
Q

What is the innervation of the cricothyroid muscle and what does injury result in?

A

superior laryngeal nerve, loss of projection and easy voice fatigability

9
Q

Where does the recurrent laryngeal nerve track?

A

runs posterior to thyroid lobes in the tracheosophageal groove. can track with inferior thyroid artery but is variable

10
Q

What structures do the right and left recurrent laryngeal nerves loop around?

A

right loops around right subclavian, left loops around aorta

11
Q

What does the recurrent laryngeal nerve innervate?

A

motor to all larynx except cricothyroid

12
Q

Injury to recurrent laryngeal nerve results in hoarseness. What additional tx is need for bilateral injury and why?

A

needs emergency trach since bilateral injury can obstruct airway

13
Q

What is the posterior medial suspensory ligament of the thyroid that is close to the RLNs and requires careful dissection?

A

Ligament of Berry

14
Q

What is the molecule that stores T3 and T4 in colloid?

A

thyroglobulin

15
Q

What is the most lateral posterior extension of thyroid tissue called? They can be rotated medially to find what structures? (left behind with subtotal thyroidectomy because of proximity).

A

Tubercles of Zuckerkandl

16
Q

What is the name of the cells that produce calcitonin?

A

Parafollicular C cells

17
Q

What is a long-term side effect of thyroxine treatment?

A

osteoporosis

18
Q

Postthyroidectomy pt develops stridor. What do you do?

A

open neck emergently to remove hematoma, can result in airway compromise

19
Q

Thyroid storm is most common after surgery in pt with undiagnosed ____?

A

Grave’s disease

20
Q

What are the following sx of?:
increased HR, fever, numbness, irritability, vomiting, diarrhea, high-output cardiac failure (most common cause of death)

A

Thyroid storm

21
Q

Describe the Wolf-Chaikoff effect which is very effective for pts in thyroid storm.

A

Patient given high doses of iodine (Lugol’s solution, potassium iodide), which inhibits TSH action on thyroid and inhibits organic coupling of iodide, resulting in less T3 and T4 release

22
Q

What is the first step in dx of asymptomatic thyroid nodule?

A

thyroid function tests

23
Q

Asymptomatic thyroid nodule FNA shows cyst fluid. It is drained and it recurs, what next?

A

thyroidectomy or lobectomy

24
Q

Asymptomatic thyroid nodule with normal TFTs what is the next step in dx?

A

FNA

25
Q

Thyroid FNA shows colloid tissue what is the tx?

A

Low chance of malignancy (

26
Q

Thyroid FNA shows follicular cells, what next and what is the malignancy rate?

A

thyroidectomy or lobectomy (5-10% malignancy rate)

27
Q

What percentage of thyroid nodules are benign?

A

85%

28
Q

What next if a thyroid nodule FNA is indeterminate?

A

Radionucleotide study

29
Q

Thyroid nodule FNA is indeterminate, radionucleotide study shows hot nodule, what next?

A

Give thyroxine for 6 months, if size does not decrease perform lobectomy

30
Q

Thyroid nodule FNA is indeterminate, radionucleotide study shows cold nodule, what next?

A

thyroidectomy or lobectomy

31
Q

Diffuse enlargement of thyroid without evidence of functional abnormality = nontoxic colloid goiter. What is the tx?

A

Tx: try to suppress with thyroxine; 131I (may be ineffective), thioamides, subtotal thyroidectomy or lobectomy on side of goiter if medical treatment ineffective

32
Q

What is the name of the thyroid lobe that occurs in 10%, extends from the isthmus toward the thymus?

A

pyramidal lobe

33
Q

What is the cyst that classically moves upward with swallowing?

A

thyroglossal duct cyst

34
Q

What is the tx for thyroglossal duct cyst and why?

A

Resection, susceptible to infection and my be premalignant. (Also need to take midportion or all of hyoid bone along with the cyst)

35
Q

What are the two main side effects of PTU and Methimazole?

A

aplastic anemia or agranulocytosis

36
Q

What is the treatment for hyperthyroidism that is good for young pts, small goiters and mild T3 and T4 elevation?

A

PTU and methimazole

37
Q

What is the treatment for hyperthyroidism that is good for pts who are poor surgical candidates or unresponsive to PTU?

A

radioactive iodine (131I)

38
Q

When is the best time to operate in pregnant women with hyperthyroidism?

A

2 trimester due to decreased risk of teratogenic events and premature labor

39
Q

What is the most common cause of hyperthyroidism and what is the pathophys?

A

Graves’ disease, IgG antibodies to TSH receptor

40
Q

What is the recurrence rate for tx of Graves’ disease with thioamides, 131I, and subtotal thyroidectomy?

A

70%, 10%, 10%

41
Q

Suspicious nodule in pt with Graves’ disease, what is the tx?

A

bilateral subtotal or total thyroidectomy

42
Q

What is the preop preparation for a pt with Graves’ disease undergoing a bilateral subtotal or total thyroidectomoy?

A

Preop preparation: PTU or methimazole until euthyroid, _-blocker, 1 week before surgery, Lugol’s solution for 10-15 days to decrease friability and vascularity (start only after euthyroid)

43
Q

What is the most common cause of thyroid enlargement?

A

toxic multinodular goiter

44
Q

Sx of toxic multinodular goiter include ___; What could precipitate sx?

A

cardiac symptoms, weight loss, insomnia, airway compromise; contrast dyes

45
Q

What is the tx for toxic multinodular goiter and single toxic nodule?

A

131I and thioamides; 131I can be less effective in some (inhomogeneous uptake by gland); subtotal thyroidectomy or lobectomy if medical treatment ineffective

46
Q

What is the most common cause of hypothyroidism in adults?

A

hashimoto’s disease

47
Q

Why can a goiter develope in Hashimoto’s disease?

A

lack of organification of trapped iodide inside gland

48
Q

What usually precipitates DeQuervains’s thyroiditis?

A

viral URI

49
Q

What is the tx for De Quervains thyroiditis?

A

steroids, ASA

50
Q

Rare condition of woody, fibrous component to thyroid that can involve adjacent strap muscles and carotid sheath • Can resemble thyroid CA or lymphoma (need biopsy) • Disease frequently results in hypothyroidism and compression. Tx is steroids and thyroxine. May need isthmectomy or trach.

A

Riedel’s fibrous struma

51
Q

What is the most common endocrine malignancy in the US?

A

thyroid CA

52
Q

What is the most common type of thyroid CA?

A

papillary

53
Q

What type of thyroid CA is the least aggressive, slow growing and has the best prognosis?

A

papillary

54
Q

What is the prognosis in papillary thyroid CA based on?

A

local invasion

55
Q

What type of thyroid cancer’s pathology has psammoma bodies and ophan Annie nuclei?

A

papillary

56
Q

Papillary thyroid CA less than what size can have a lobectomy instead of total thyroidectomy?

A
57
Q

Papillary Thyroid CA with clinically positive cervical nodes or extrathyroidal tissue requires what additional tx?

A

ipsilateral MRND

58
Q

Papillary thyroid CA with metastatic disease, residual local disease, positive lymph nodes or capsular invasion requires what addtional tx?

A

131I 6 weeks after surgery

59
Q

When would you give XRT for papillary thyroid CA

A

unresectable or no response to 131I

60
Q

What is the 5 year survival in papillary thyroid CA?

A

95%

61
Q

Enlarged lateral neck lymph node that shows normal appearing tissue. What is it and what is the tx?

A

papillary thyroid CA with lymphatic spread, total thyroidectomy and MRND

62
Q

What percentage of follicular thyroid carcinoma has metastatic disease at the time of presentation?

A

50%

63
Q

What is the route of metastasis and most common site with follicular thyroid carcinoma?

A

hematogenous, bone

64
Q

If thyroid nodule FNA shows just follicular cells, what is the chance of malignancy?

A

10%

65
Q

Lobectomy for follicular cells on thyroid FNA. Pathology shows adenoma or follicular cel hyperplasia. What next?

A

nothing

66
Q

What size thyroid lesions showing follicular CA need total thyroidectomy?

A

> 1 cm

67
Q

Follicular thyroid CA with clinically positive cervical nodes or extrathyroidal tissue involvement. What additional tx is needed?

A

ipsilateral MRND

68
Q

Follicular thyroid CA > 1 cm or extrathyroidal disease need what tx in addition to thyroidectomy?

A

131I 6 weeks after surgery

69
Q

What is the 5 year survival rate with follicular thyroid CA?

A

70%

70
Q

What does the pathology show in medullary thyroid carcinoma?

A

amyloid deposition

71
Q

What can be used to test for medullary thyroid CA? Causes increase in calcitonin?

A

Gastrin

72
Q

From what cells does Medullary thyroid carcinoma arise and what do they secrete?

A

parafollicular C cells, calcitonin

73
Q

What two other conditions should be screened for if medullary thyroid carcinoma is diagnosed?

A

hyperparathyroidism and pheochromocytoma

74
Q

What are two sx of elevated calcitonin?

A

flushing and diarrhea

75
Q

Tx for medullary thyroid carcinoma is total thyroidectomy with what other dissection?

A

central neck

76
Q

Prophylactic thyroidectomy and central node dissection in MEN IIa or IIb patients at what age?

A

2 years

77
Q

What can be monitored for disease recurrence in medullary thyroid carcinoma?

A

calcitonin

78
Q

What is the 5 year survival in medullary thyroid carcinoma?

A

50%

79
Q

What is the 5 year survival for anaplastic thyroid cancer?

A

0%

80
Q

What types of thyroid CA is 131I effective?

A

papillary and follicular only