Surgical Recall Ch 58: Thyroid Gland

Front 1

Define the arterial blood supply of the thyroid.

Back 1

Two arteries:

1) Superior thyroid artery (1st branch of the external carotid)

2) Inferior thyroid artery (branch of the thyrocervical trunk) (or rarely IMA artery)

for more info see Recall P.440

Front 2

What is the venous drainage of the thyroid?

Back 2

Three vains:
1) Superior Thyroid Vein
2) Middle Thyroid Vein
3) Inferior Thyroid Vein

for more info see Recall P.440

Front 3

Name the thyroid lobe appendage coursing toward the hyoid bone from around the thyroid isthmus.

Back 3

pyramidal lobe

Front 4

What percentage of patients have a pyramidal lobe?

Back 4

approx. 50%

Front 5

What veins do you first see after opening the platysma muscle when performing a thyroidectomy?

Back 5

anterior jugular veins

Front 6

Name the lymph node group around the pyramidal thyroid lobe.

Back 6

Delphian lymph node group

Front 7

What is the thyroid isthmus?

Back 7

Midline tissue border between the left and right thyroid lobes

Front 8

Which ligament connects the thyroid to the trachea?

Back 8

Ligament of Berry

Front 9

What is the IMA (not I.M.A.) artery?

Back 9

a small inferior artery to the thyroid from the aorta or innominate artery

Front 10

What percentage of patients have an IMA artery?

Back 10

approx 3%

Front 11

Name the most posterior extension of the lateral thyroid lobes.

Back 11

Tubercle of Zuckerkandl

Front 12

Which paired nerves must be carefully identified during a thyroidectomy?

Back 12

The recurrent laryngeal nerves, which are found in the tracheoesophageal grooves and dive behind the cricothyroid muscle; damage to these nerves paralyzes laryngeal abductors and causes hoarseness if unilateral and airway obstruction if bilateral

Front 13

Which nerve (other than the recurrent laryngeal nerve) is at risk during a thyroidectomy and what are the symptoms?

Back 13

The superior laryngeal nerve; if damaged, patient will have a deeper and quieter voice (unable to hit high pitches)

Front 14

What is TRH?

Back 14

thyrotropin releasing hormone released from the hypothalamus; causes release of TSH

Front 15

What is TSH?

Back 15

Thyroid-stimulating hormone released by the anterior pituitary; causes release of thyroid hormone from the thyroid

Front 16

What are the thyroid hormones?

Back 16

T3 and T4

Front 17

What is the negative feedback loop?

Back 17

T3 and T4 feed back negatively on the anterior pituitary; (causing decreased release of TSH in response to TRH)

Front 18

What is the most common site of conversion of T4 to T3?

Back 18

peripheral (e.g., liver)

Front 19

What is synthroid (levothyroxine): T3 or T4?

Back 19

T4

Front 20

What is the half life of synthroid (levothyroxine)?

Back 20

7 days

Front 21

What do parafollicular cells secrete?

Back 21

Calcitonin

Front 22

What % of people have a thyroid nodule?

Back 22

about 5%

Front 23

What is the differential diagnosis of a thyroid nodule?

Back 23

Multinodular goiter
Adenoma
Hyperfunctioning adenoma
Cyst
Thyroiditis
Carcinoma/lymphoma
Parathyroid carcinoma

Front 24

Name 3 types of non-thyroidal neck masses.

Back 24

1) inflammatory lesions (e.g., abscess, lymphadenitis)
2) congenital lesions (i.e., thyroglossal duct [midline], branchial cleft cyst [lateral])
3) Malignant lesions: lymphoma, metastases, squamous cell carcinoma

Front 25

What studies can be used to evaluate a thyroid nodule?

Back 25

U/S-solid or cystic nodule
Fine needle aspiration (FNA) -> cytology
123-I scintiscan - hot or cold nodule

Front 26

What is the diagnostic test of choice for a thyroid nodule?

Back 26

FNA

Front 27

What is the % of false negative results on FNA for thyroid nodule?

Back 27

approx. 5%

Front 28

What is meant by hot vs. cold nodule?

Back 28

Nodule uptake of IV 131-I or 99-mT

Hot = increased uptake = functioning/hyperfunctioning nodule

Cold = decreased uptake = nonfunctioning nodule

Front 29

What are the indications for a 123-I scintiscan?

Back 29

1) Nodule with multiple "nondiagnostic" FNA with low TSH

2) Nodule with thyrotoxicosis and low TSH

Front 30

What is the role of thyroid suppression of a thyroid nodule?

Back 30

Diagnostic and therapeutic; administration of thyroid hormone suppresses TSH secretion, and up to half of the benign thyroid nodules will disappear!

Front 31

In evaluating thyroid nodule, what aspects of the history suggests thyroid carcinoma?

Back 31

1) neck radiation
2) family history - thyroid ca or MEN-II
3)Young age (esp children)
4) Males more than females

Front 32

In evaluating thyroid nodule, what signs suggests thyroid carcinoma?

Back 32

1) single nodule
2) cold nodule
3) increased calcitonin levels
4) lymphadenopathy
5) hard, immobile nodule

Front 33

In evaluating thyroid nodule, what symptoms suggests thyroid carcinoma?

Back 33

1) voice change (vocal cord paralysis)
2) dysphagia
3) discomfort (in neck)
4) rapid enlargement

Front 34

What is the most common cause of thyroid enlargement?

Back 34

Multinodular goiter

Front 35

What are the indications for surgery for multinodular goiter?

Back 35

cosmetic deformity, compressive symptoms, cannot rule out cancer

Front 36

What is Plummer's disease?

Back 36

toxic multimodular goiter

Front 37

What % of cold thyroid nodules are malignant?

Back 37

approximately 25% in adults

Front 38

What % of multinodular masses are malignant?

Back 38

approximately 1%

Front 39

What is the treatment of a patient with radiation exposure, thyroid nodule, and negative FNA?

Back 39

most experts would remove the nodule surgically because of the high risk of radiation

Front 40

What should be done with thyroid cyst aspirate?

Back 40

send to cytopathology

Front 41

Name the 5 main types of thyroid carcinoma and their relative percentages.

Back 41

1) Papillary carcinoma: 80% (popular=papillary)
2) Follicular adenoma: 10%
3) Medullary carcinoma: 5%
4) Hurthle cell carcinoma: 4%
5) Anaplastic/undifferentiated carcinoma: 1% to 2%

Front 42

What are the signs/symptoms of thyroid carcinoma?

Back 42

mass/nodule
lymphadenopathy
most are EUTHYROID

Front 43

What comprised the workup of thyroid carcinoma?

Back 43

FNA
thyroid u/s
TSH
calcium level
CXR
+/- scintiscan 123-I

Front 44

What oncogenes are associated with thyroid cancers?

Back 44

Ras gene family and RET proto-oncogene

Front 45

With what condition is papillary adenocarcinoma of the thyroid associated?

Back 45

Gardner's syndrome and neck irradiation

Front 46

What are the histologic findings in papillary thyroid adenocarcinoma?

Back 46

psammoma bodies (remember p=psammoma=papillary=popular)

Front 47

Describe the route and rate of spread of papillary thyroid cancer?

Back 47

most spread by lymphatics (cervical adeopathy); spread occurs slowly

Front 48

What is the 131-I uptake in papillary thyroid cancer?

Back 48

good uptake

Front 49

What is the 10yr survival rate for papillary thyroid cacner?

Back 49

approx. 95%

Front 50

What is the treatment for a 1.5cm or smaller papillary carcinoma with no history of neck radiation expose?

Back 50

Options;
1) thyroid lobectomy and isthmectomy
2) near-total thyroidectomy
3) total thyroidectomy

Front 51

What is the treatment for a 1.5cm or larger papilalry carcinoma that is bilateral, has + cervical node mets, or a history of radiation exposure?

Back 51

total thyroidectomy

Front 52

What is the treatment for lateral palpable cervical lymph nodes?

Back 52

ipsilateral modified neck dissection

Front 53

What is the treatment for central palpable cervical lymph nodes?

Back 53

central neck dissection

Front 54

Do + cervical nodes affect the prognosis for papilalry carcinoma?

Back 54

NO!

Front 55

What postoperative medication shoudl be administered?

Back 55

thyroid hormone replacement, to suppress TSH

Front 56

What is a postoperative treatment option for papillary carcinoma?

Back 56

Postoperative 131-I scan can locate residulal tumor and distant mets that can be treated with ablative doses od 131-I

Front 57

What the 7 P's of Papillary thyroid cancer?

Back 57

1) Papillary cancer
2) Popular (most common)
3) Psammoma bodies
4) Palpable lymph nodes (spreads most commonly by lymphatics, seen in up to 1/3 of patients)
5) Positive I-131 uptake
6) Positive prognosis
7) Postoperative I-131 scan to diagnose/treat mets

Front 58

What % of thyroid cancer does follicular adenocarcinoma comprise?

Back 58

approx. 10%

Front 59

Describe the nodule consistency with follicular adenocarcinoma.

Back 59

rubebry, encapsulated

Front 60

What is the route of spread of follicular adenocarcinoma?

Back 60

Hematogenous

(more aggressive than papillary cancer)

Front 61

What is the male to female ratio for follicular adenocarcinoma of the thyroid?

Back 61

1:3

Front 62

What is the I-131 uptake for follicular adenocarcinoma?

Back 62

good uptake

Front 63

What is the 10yr survival for follicular adenocarcinoma?

Back 63

85%

Front 64

Can the diagnosis for follicular thyroid cancer be made by FNA?

Back 64

No; tissue structure is needed for diagnosis of cancer

Front 65

What histologic findings define malignancy in follicular cancer?

Back 65

capsular or blood vessel invasion

Front 66

What is the most common site of distant mets for follicular cancer?

Back 66

bone

Front 67

What is the treatment for follicular cancer?

Back 67

total thyroidectomy

Front 68

What is the postoperative treatment option if a follicular carcinoma is malignant?

Back 68

post-operative I-131 scan for diagnosis/treatment

Front 69

What are the 5 F's of follicular cancer?

Back 69

1)Follicular Cancer:

2)Far-away metastasis (spreads hematogenously)

3)Female (3:1)

4)FNA.....NOT (FNA cannot diagnose cancer)

5)Favorable prognosis

Front 70

What is Hurthle Cell thyroid cancer?

Back 70

thyroid cancer of Hurthle cells

Front 71

What % of thyroid cacners does Hurthle cell compose?

Back 71

approx 5%

Front 72

What is the cell of origin in Hurthle cell?

Back 72

follicular cells

Front 73

What is the I-131 uptake in Hurthle cell?

Back 73

NO UPTAKE

Front 74

How is a diagnosis of Hurthle cell thyroid cancer made?

Back 74

FNA can identify cells, but malignancy can only be determined by tissue histology (just like in follicular cell)

Front 75

What is the route of metastasis in Hurthle cell?

Back 75

lymphatic more than hematogenous

Front 76

What is the treatment for Hurthle cell?

Back 76

total thyroidectomy

Front 77

What % of thyroid cancer does medullary carcinoma compose?

Back 77

approx 5%

Front 78

With what other conditions is medullary thryoid cancer associated?

Back 78

MEN II; autosomal dominant

Front 79

What is the histology of medullary thryoid cancer?

Back 79

Amyloid (think; aMyloid=Medullary)

Front 80

What does medullary thyroid cancer secrete?

Back 80

calcitonin

Front 81

What is the appropriate stimulation test for medullary carcinoma?

Back 81

pentagastrin (causes an increase in calcitonin)

Front 82

Describe the route of spread of medullary carcinoma.

Back 82

lymphatic and hematogenous distant spread

Front 83

How is the diagnosis of medullary carcinoma made?

Back 83

FNA

Front 84

What is the I-131 uptake for medullary carcinoma?

Back 84

poor uptake

Front 85

What is the prognosis for medullary thyroid cancer?

Back 85

10yr survival rate is 50%;

Cure rate for occult tumors found in MEN family members being screened for increaded calcitonin approached 95%

If detected when clinically palpable, cure rate is less than 20%

Front 86

What is the treatment for medullary thyroid cancer?

Back 86

total thyroidectomy and median lymph node dissection

also modified neck dissection if lateral cervical nodes are positive

Front 87

What are the 5 M's of medullary carcinoma?

Back 87

1)Medullary cancer:
2)MEN-II
3)aMyloid
4)Median lymph node dissection
5)Modified neck dissection if lateral nodes are positive

Front 88

What is another name for anaplastic thyroid carcinoma?

Back 88

undifferentiated carcinoma

Front 89

What is anaplastic thyroid carcinoma?

Back 89

an undifferentiated cacner arising in approximately 75% of previously differentiated cancers (most commonly, follicular carcinoma)

Front 90

What % of all thyroid cancers does anaplastic carcinoma comprise?

Back 90

approx. 2%

Front 91

What is the gender preference for anaplastic carcinoma?

Back 91

occurs in women more than men

Front 92

What are the histologic findings in anaplastic carcinoma?

Back 92

giant cells, spindle cells

Front 93

What is the I-131 uptake in anaplastic carcinoma?

Back 93

very poor

Front 94

How is a diagnosis of anaplastic carcinoma made?

Back 94

FNA (large tumor)

Front 95

What is the major differential diagnosis for anaplastic carcinoma?

Back 95

thyroid lymphoma (much better prognosis!)

Front 96

What is the treatment for a small anaplastic carcinoma?

Back 96

total thyroidectomy +/- external beam xray therapy

Front 97

What is the treatment for airway compromise in anaplastic carcinoma?

Back 97

debulking surgery and tracheostomy

Front 98

What is the prognosis for anaplastic thyroid carcinoma?

Back 98

dismal - most are stage IV at presentation (3% alive at 5 years)

Front 99

What lab value MUST be followed postoperatively after a thyroidectomy?

Back 99

CALCIUM;

can be decreased secondary to thyroid damage;

during lobectomy the parathyroids must be spared and their blood supply protected; if blood supply is compromised intraoperatively they can be autografted into the sternocleidomastoid muscle or into the forearm

Front 100

What is the differential diagnosis of postoperative dyspnea after a thyroidectomy?

Back 100

Neck hematoma (remove sutures and clot at the BEDSIDE)

or

BILATERAL recurrent laryngeal nerve damage

Front 101

What is a "lateral aberrant rest" of the thyroid?

Back 101

it is a misnomer, it is papillary cancer of a lymph node from a metastasis

Front 102

What is the most common cause of hyperthyroidism?

Back 102

Grave's disease

Front 103

What is Grave's disease?

Back 103

diffuse goiter with hyperthyroidism, exopthalmos, and pretibial myxedema

Front 104

What is the etiology of Grave's disease?

Back 104

caused by curculating antibodies that stimulate TSH receptors on thyroid follicular cells and cause deregulated production of thyroid hormones

Front 105

What is the female to male ratio for Grave's disease?

Back 105

6:1

Front 106

What specific physical finding is assocaited with Grave's disease?

Back 106

exopthalmos

Front 107

How is the diagnosis of Grave's disease made?

Back 107

increased T3, T4, and anti-TSH receptor antibodies, decreased TSH, global uptake of I-131 radionucleotide

Front 108

Name 3 treatment modalities for Grave's disease?

Back 108

1) Medical blockade: iodide, propranolol, propylthiouracil (PTU), methimazole, Lugol's solution (potassium iodide)

2) Radioiodide ablation: most popular therapy

3) Surgical resection: bilateral subtotal thyroidectomy

Front 109

What are the possible indicatiosn for surgical resection of Grave's disease?

Back 109

suspicious nodule; if patient is noncompliant or refractory to medicines, pregnant, a child, or if patient refuses radioiodide therapy

Front 110

What is the major complication for either radioiodide therapy or surgery for Grave's disease?

Back 110

hypothyroidism

Front 111

What does PTU stand for?

Back 111

propylthiouracil

Front 112

What is another name for toxic multinodular goiter?

Back 112

Plummer's syndrome

Front 113

What is toxic multinodular goiter?

Back 113

multiple thyroid nodules with one or more producing thyroid hormone; resulting in a hyperfunctioning thyoid (hyperthyroidism or a "toxic" thyroid state)

Front 114

How is a hyperfunctioning nodule localized?

Back 114

I-131 radionucleotide scan

Front 115

What is the treatment for toxic multinodular goiter?

Back 115

surgically remove the hyperfunctioning nodule(s) with lobectomy or near-total thyroidectomy

Front 116

What is Pemberton's sign?

Back 116

A large goiter causes plethora of head with rasing of both arms

Front 117

What are the features of acute thyroiditis?

Back 117

painful, swollen thyroid
fever
overlying skin erythema
dysphagia

Front 118

What is the cause of ACUTE thyroiditis?

Back 118

Bacteria (usually Staph or Strep) usually caused by a thyroglossal fistula or anatomic variant

Front 119

What is the treatment of acute thyroiditis?

Back 119

antibiotics, drainage of abscess, needle aspiration for culture; most patients need defitive surgery later to remove the fistula

Front 120

What are the features of subacute thyroiditis?

Back 120

glandular swelling, tenderness, often follows URI, elevated ESR

Front 121

What is the cause of subactuet thyroiditis?

Back 121

Viral infection

Front 122

What is the treatment for subacute thyroiditis?

Back 122

Supportive: NSAIDS +/- steroids

Front 123

What is De Qervain's thyroiditis?

Back 123

just another name for subacute thyroiditis cased by a virus (think: DeQuerVain=Virus)

Front 124

What are the most common organisms causing acute suppurative thyroiditis?

Back 124

Staphylococcus

Streptococcus

Front 125

What are the two types of chronic thyroiditis?

Back 125

1) Hashimoto's
2) Reidel's

Front 126

What are the features of Hashimoto thyroiditis?

Back 126

Firm, rubbery gland, 95% in women, lymphocyte invasion

Front 127

What is the etiology of Hashimoto disease?

Back 127

autoimmune (think hasimOTO - AUTOimmune)

Front 128

What lab tests are used to diagnose Hashimoto thyroiditis?

Back 128

Antithyroglobulin and microsomal antibodies

Front 129

What is Riedel's thyroiditis?

Back 129

Benign inflammatory thyoid enlargemant with fibrosis of thyroid

Patients present with painless, large thyroid

Fibrosis may involve surrounding tissues