Chapter 22: Thyroid Flashcards Preview

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Flashcards in Chapter 22: Thyroid Deck (282):
1

Embryology: thyroid

Forms from the 1st and 2nd pharyngeal arches (not from pouches)

2

Released from the hypothalamaus; acts on the anterior pituitary gland and causes release of TSH

Thyrotropin-releasing factor (TRF)

3

Released from the anterior pituitary gland; acts on the thyroid gland to release T3 and T4 (through a mechanism that involves increased cAMP)

Thyroid-stimulating hormone (TSH)

4

What controls the release of TRF and TSH?

TRF and TSH release are controlled by T3 and T4 through a negative feedback loop

5

1st branch off the external carotid artery

Superior thyroid artery

6

Off thyrocervical trunk; supplies both the inferior and superior parathyroids

Inferior thyroid artery

7

Where do you ligate the inferior thyroid artery?

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

8

Occurs in 1%
- Arises form the innominate or aorta and goes to the isthmus

Ima artery

9

Drain into internal jugular veins

Superior and middle thyroid veins

10

Where do superior and middle thyroid veins drain?

Internal jugular vein

11

Where does the inferior thyroid vein drain?

Innominate vein

12

Nerve:
- Motor to cricothyroid muscle
- Runs lateral to thyroid lobes
- Tracks close to superior thyroid artery but is variable
- Injury results in loss of projection and easy voice fatiguability (opera singers)

Superior laryngeal nerve

13

Nerve:
- Motor to all of larynx except cricothyroid muscle
- Runs posterior to thyroid lobes in the tracheoesophageal groove
- Can track with inferior thyroid artery but variable.

Recurrent laryngeal nerve

14

Where does recurrent laryngeal nerve run?

Posterior to thyroid lobes in the tracheoesophageal groove

15

Path of right vs left recurrent laryngeal nerve

Left RLN: loops around aorta
Right RLN: loops around innominate artery

16

What can happen with injury to the recurrent laryngeal nerve?

Injury results in hoarseness; bilateral injury can obstruct airway -> need emergency tracheostomy

17

What can happen with injury to the superior laryngeal nerve?

Injury results in loss of projection and easy voice fatiguability (opera singers)

18

Nerve:
- Occurs in 2%
- More common on the right

Non-recurrent laryngeal nerve

19

Nerve: risk of injury is higher for this nerve during thyroid surgery

Non-recurrent laryngeal nerve

20

Posterior medial suspensory ligament close to recurrent laryngeal nerves; need careful dissection.

Ligament of Berry.

21

Stores T3 and T4 in colloid

Thyroglobulin

22

Ratio of plasma T4:T3

15:1.
- T3 is the more active form (is tyrosine + iodine)

23

Tyrosine + iodine

T3

24

How is most T3 produced?

Most T3 is produced in the periphery from T4 to T3 conversion by deiodinases

25

Link iodine and tyrosine together

Peroxidases

26

Separate iodine from tyrosine

Deiodinases

27

Thyroid hormone transport; binds the majority of T3 and T4 in circulation

Thyroxine-binding globulin

28

Most sensitive indicator of gland function

TSH

29

Most lateral, posterior extension of thyroid tissue
- Rotate medially to find recurrent laryngeal nerves.

Tubercles of Zuckerkandl

30

What portion of the thyroid is left behind with subtotal thyroidectomy?

Tubercles of Zuckerkandl secondary to proximity to RLNs.
- Tubercles of Zuckerkandl: most lateral, posterior extension of thyroid tissue.

31

Produce calcitonin

Parafollicular C cells

32

Goals of thyroxine treatment

TSH levels should fall 50%

33

Long term side effect of thyroxine treatment

Osteoporosis

34

Treatment for post-thyroidectomy stridor

Open neck and remove hematoma emergently -> can result in airway compromise, can also be due to bilateral RLN injury -> would need emergent tracheostomy.

35

Symtoms: Tachycardia, fever, numbness, irritability, vomiting, diarrhea, high-output cardiac failure (MCC death)

Thyroid storm

36

MCC death in thyroid storm

High output cardiac failure

37

When is thyroid storm MC post-operatively??

MC after surgery in patient with undiagnosed Grave's disease

38

Treatment: thyroid storm

Beta-blockers, PTU, Lugol's solution (KI), cooling blankets, oxygen, glucose.
- Emergent thyroidectomy rarely indicated.

39

First line treatment of thyroid storm

Beta-blockers

40

- Very effective for thyroid storm
- Pt 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

Wolff-Chaikoff effect

41

90% of thyroid nodules are..

Benign and in females

42

Best initial test for a thyroid nodule

FNA and thyroid function tests

43

Tx: FNA shows follicular cells

Lobectomy (10% CA risk)

44

Tx: FNA shows thyroid CA

Thyroidectomy or lobectomy and appropriate treatment

45

Tx: FNA shows cyst fluid

Drain fluid.
- If it secures or is bloody -> lobectomy

46

Tx: FNA shows colloid tissue

Most likely colloid goiter; low chance of malignancy (

47

Tx: FNA shows normal thyroid tissue and TFTs are elevate

Likely solitary toxic nodule.
- Tx: if asymptomatic can just monitor; PTU and I(131) if symptomatic.

48

FNA: % determinate vs % indeterminate

- Determinant in 80% -> follow appropriate treatments.
- Indeterminate in 20% -> get radionuclide study

49

If FNA is indeterminate?

Get radionuclide study.
Will show..
- Hot nodule vs Cold nodule

50

Tx: hot nodule on radionuclide study

If asymptomatic can monitor. PTU and I(131) is symptomatic.

51

Tx: cold nodule on radionuclide study

Lobectomy (more likely malignant than hot nodule)

52

Any abnormal thyroid enlargement

Goiter

53

Most identifiable cause of goiter

Iodine deficiency
- Tx: iodine replacement

54

Diffuse thyroid enlargement without evidence of functional abnormalities

Nontoxic colloid goiter

55

When would you operate on goiter?

Unusual to have to operate unless goiter is causing airway compression or there is a suspicious nodule.
- Tx: subtotal or total thyroidectomy for symptoms or if suspicious nodule; subtotal has decreased risk of RLN injury.

56

Goiter:
- Usually secondary (vessels originate from superior and inferior thyroid arteries)
- Primary substernal goiter - rare (vessels originate from innominate artery)

Substernal goiter

57

Most likely from acquired disease with inferior extensions of a normally placed gland (e.g. substernal goiter)

Mediastinal thyroid tissue

58

- Occurs in 10%
Extends form the isthmus toward the thymus

Pyramidal lobe

59

Thyroid tissue that persists in foramen cecum at the base of the tongue.
- S/S: dysphagia, dyspnea, dysphonia
- 2% malignancy risk
- Is the only thyroid tissue in 70% of patients who have it

Lingual thyroid

60

Tx: lingual thyroid

Thyroxine suppression, abolish with I(131)
- Resection if worried about CA or if it does not shrink after medical therapy.

61

- Classically moves upward with swallowing
- Susceptible to infection and may be premalignant

Thyroglossal duct cyst

Tx: resection -> need to take mid portion or all of hyoid bone alone with the thyroglossal duct cyst (Sistrunk procedure)

62

Treatment of thyroglossal duct cysts

Sistrunk procedure:
- Resection -> take mid portion or all of hyoid bone along with the thyroglossal duct cyst.

63

Indications for propylthiouracil (PTU) and methimazole

Young patients.
Small goiters.
Mild T3 and T4 elevation.

64

- Safe in pregnancy
- Inhibits peroxidases and prevents iodine-tyrosine coupling
- Side effects: aplastic anemia, agranulocytosis (rare)

PTU (thioamides)

65

- Inhibits peroxidases and prevents iodine-tyrosine coupling
- Side effects: cretinism in newborns (crosses placenta), aplastic anemia, agranulocytosis (rare)

Methimazole

66

- Good for patients who are poor surgical risks or unresponsive to PTU
- Do not use in children or during pregnancy -> can traverse placenta

Radioactive iodine (I-131)

67

- Good for cold nodules, toxic adenomas or multi nodular goiters not responsive to medical therapy, pregnant patients not controlled with PTU, compressive symptoms

Thyroidectomy

68

Best time to operate on thyroid during pregnancy.

2nd trimester: decreased risk of teratogenic events and premature labor.

69

Operation can leave the patient euthyroid

Subtotal thyroidectomy

70

Symptoms: women, exophthalmos, pretrial edema, atrial fibrillation, heat intolerance, thirst, increased appetite, weight loss, sweating, palpitations

Graves' disease

71

MCC hyperthyroidism (80%)

Graves' disease

72

What is the cause of Grave's disease?

Caused by IgG antibodies to TSH receptor (long-acting thyroid stimulates [LATS], thyroid-stimulating immunoglobulin [TSI])

73

Decreased TSH.
Increased T3 and T4.
LATS level.
Diffuse increase in 123-i uptake (thyroid scan).

Graves' disease

74

Tx: Graves' disease

Thioamides (50% recurrence)
131-i (5% recurrence)
Thyroidectomy if medical therapy fails.

75

Graves' disease: pre-op preparation

PTU until euthyroid. B-blocker. Lugol's solution for 14 days to decrease friability and vascularity (start only after euthyroid).

76

Graves' disease: operation

Bilateral subtotal (5% recurrence) or total thyroidectomy (need lifetime thyroxine replacement)

77

Graves' disease: indications for surgery

Noncompliant patient, reucrrence after medical therapy, children, pregnant women not controlled with PTU, or concomitant suspicious thyroid nodule

78

- Women, age > 50 years, usually nontoxic 1st
- Symptoms: tachycardia, weight loss, insomnia, airway compromise, symptoms can be precipitated by contrast dyes
- Caused by hyperplasia secondary to chronic low-grade TSH stimulation

Toxic multinodular goiter

79

Tx: toxic multinodular goiter

Most consider surgery (subtotal or total thyroidectomy) the preferred initial treatment for toxic multi nodular goiter, but a trial of i-131 should be considered, especially in the elderly and frail.
- If compression of a suspicious nodule is present, need to go with surgery

80

- Women, younger, usually > 3cm to be symptomatic, function autonomously.

Single toxic nodule

81

Dx and Tx: Single toxic nodule

Dx: thyroid scan (hot nodule) - 20% of hot nodules eventually cause symptoms
Tx: thioamides and 131-i (95% effective). lobectomy if medical treatment ineffective

82

Rare causes of hyperthyroidism

Trophoblastic tumors, TSH-secreting pituitary tumors.

83

MCC hypothyroidism in adults

Hashimoto's disease

84

- Enlarged gland, painless, chronic thyroiditis
- Women, history of childhood XRT
- Can cause thyrotoxicosis in the acute early stage

Hashimoto's disease

85

What causes Hashimotos' disease?

- Caused by both humeral and cell-mediated autoimmune disease (microsomal and thyroglobulin antibodies)
- Goiter secondary to lack of organification of trapped iodide inside gland

86

What does pathology show for Hashimoto's thyroiditis?

Pathology shows a lymphocytic infiltrate

87

Tx: Hashimotos' thryoidits

Thyroxine (first line), partial thyroidectomy if continues to grow despite thyroxine, if nodules appear, or if compression symptoms occur

88

- Usually secondary to contiguous spread
- Bacterial URI usual precursors (staph/strep)
- Normal thyroid function tests, fever, dysphagia, tenderness

Bacterial thyroiditis (rare)

89

Tx: bacterial thyroiditis

Antibiotics
- May need lobectomy to r/o CA in pts w/ unilateral swelling and tenderness.
- May need total thyroidectomy for persistent inflammation

90

- Can be a/w hyperthyroidism initially
- Viral URI precursor, tender thyroid, sore throat, mass, weakness, fatigue, women.
- Elevated ESR.

De Quervain's thyroiditis

91

Tx: De Quervain's thyroiditis

Steroids and ASA
- May need lobectomy to r/o CA in pts w/ unilateral swelling and tenderness.
- May need total thyroidectomy for persistent inflammation

92

- Woody, fibrous component that can involve adjacent strap muscles and carotid sheath
- Can resemble thyroid CA or lymphoma (need biopsy)
- Disease frequently results in hypothyroidism and compression symptoms

Riedel's fibrous struma (rare)

93

What is Riedel's fibrous struma associated with?

Sclerosing cholangitis.
Fibrotic disease.
Methysergide Tx.
Retroperitoneal fibrosis.

94

Tx: Riedel's fibrous struma

Steroids and thyroxine
- May need isthmectomy or tracheostomy for airway symptoms
- If resection needed, watch for RLNs.

95

Most common endocrine malignancy in the US

Thyroid cancer

96

% Chance of malignancy with follicular cells on FNA

5-10% chance of malignancy

97

DDx follicular cells on FNA

Follicular cell adenoma vs follicular hyperplasia vs follicular cell CA

98

Thyroid CA: characteristics with increased chance of malignancy

Solid, solitary, cold, slow growing, hard, male, age > 50, previous neck XRT, MEN 2a or 2b

99

DDx: sudden growth of thyroid cancer

Could be hemorrhage into previously undetected nodule or malignancy

100

Patients can present with voice changes or dysphagia

Think about thyroid cancer

101

- Colloid, embryonal, fetal -> no increased cancer risk.
- Tx: still need lobectomy to prove it is an adenoma

Follicular adenoma

102

MC (85%) thyroid cancer

Papillary thyroid carcinoma

103

- Least aggressive, slow growing, has the best prognosis; women, children
- Older age (>40-50yrs) predicts a worst prognosis.
- Children are more likely to be node positive (80%) than are adults (20%)

Papillary thyroid carcinoma

104

Risk factors of papillary thyroid carcinoma

Childhood XRT (very increased risk) -> MC tumor following neck XRT

105

How do you ascertain prognosis of papillary thyroid carcinoma?

Lymphatic spread 1st but is not prognostic -> prognosis based on local invasion

106

Papillary thyroid CA: mets?

Rare - lung

107

Path: papillary thyroid CA

psammoma bodies (calcium) and Orphan Annie nuclei

108

Tx: papillary thyroid CA

- Minimal/incidental ( 1cm
- Clinically + cervical LN: need ipsilateral MRND
- Extrathyroidal tissue involvement: need ipsilateral MRND
- Mets, residual local disease, +LN, capsular invasion -> 131-i (4-6wks after surgery
- XRT only for unresectable disease not responsive to 131-i

109

When would you do total thyroidectomy for papillary thyroid carcinoma?

Bilateral lesions, multicentricity, history of XRT, positive margins, tumors > 1cm

110

Survival rate papillary thyroid CA

95% 5-year survival rate; death secondary to local disease

111

Dx: enlarged lateral neck lymph node that shows normal-appearing thyroid tissue.
Tx: ?

Dx: Papillary thyroid CA with lymphatic spread (lateral aberrant thyroid tissue)
Tx: total thyroidectomy and MRND; 131-i (4-6weeks after surgery)

112

- Hematogenous spread (bone most common) -> 50% have metastatic disease at the time of presentation.
- More aggressive than thyroid papillary cell CA; older adults (50-60s), women

Follicular thyroid carcinoma

113

What if FNA shows just follicular cells?

10% have chance of malignancy. Need lobectomy.

114

Tx: follicular thyroid carcinoma

Lobectomy -> if path shows adenoma or follicular cell hyperplasia, nothing else needed.
- Follicular CA: total thyroid for lesions > 1 or extra thyroid disease
- Clinically positive cervical nodes: ipsilateral MRND.
- Extrathyroid involvement: ipsilateral MRND.
- Lesions > 1cm or extrathyroid: 131-i (4-6 wks after surgery)

115

Survival rate follicular thyroid carcinoma

70% 5-year survival rate; prognosis based on stage

116

- Can be a/w MEN 2a, 2b (diarrhea)
- Usually the 1st manifestation of MEN 2a / 2b (diarrhea)
- Tumor arises from parafollicular C cells (which secrete calcitonin)
- C-cell hyperplasia considered premalignant

Medullary thyroid carcinoma

117

Path: medullary thyroid carcinoma

Shows amyloid deposition

118

What do you need to screen for with medullary thyroid carcinoma?

Hyperparathyroidism and pheochromocytoma.

119

Metastatic risk for medullary thyroid carcinoma

- Lymphatic spread: most have involved nodes at time of diagnosis
- Early mets to lung, liver, and bone.

120

MC site of mets in follicular thyroid carcinoma

Bone

121

Treatment: medullary thyroid carcinoma

Tx: total thyroid with central neck node dissection.
- MRND: if +nodes (bilateral MRND if both lobes have tumor) or if extra thyroidal disease present.
- XRT may be useful for unresectable local and distant metastatic disease.

122

When would you consider prophylactic thyroidectomy and central node dissection?

In medullary thyroid carcinoma.
- in MEN 2a (at age 6 years) or 2b (at 2 years)

123

What prevents attempt at cure of medullary thyroid carcinoma?

Liver and bone metastases

124

Monitor for recurrence of medullary thyroid carcinoma

Calcitonin levels

125

Survival rate of medullary thyroid carcinoma

50% 5-year survival rate, prognosis based on presence of regional and distant metastasis.

126

- Most are benign, presents in older patients.
- Mets go to bone and lung if malignant.
- Tx?

Hurthle cell carcinoma.
Tx: total thyroidectomy, MRND for clinically positive nodes

127

- Elderly patients with long-standing goiters
- Most aggressive thyroid CA
- Rapidly lethal, usually beyond surgical management at diagnosis.

Anaplastic thyroid cancer

128

Tx: Anaplastic thyroid carcinoma

Total thyroidectomy for the rare lesion that can be resected.
- Can perform palliative thyroidectomy for compressive symptoms or give palliative chemo-XRT

129

Survival rate anaplastic thyroid cancer

Rapidly lethal: 0% at 5-year

130

What is XRT effective for?

Papillary, follicular, medullary, and Hurthle cell thyroid CA

131

What is 131-i effective for?

Papillary and follicular thyroid CA only

132

How do you use 131-i?

- Can cure bone and lung mets
- Give 4-6 wks after surgery when TSH levels are highest.
- Do not give thyroid replacement until after treatment with 131-i -> would suppress TSH and uptake of 131-i.

133

Indications for 131-i

Used only for papillary and follicular thyroid CA
- Recurrent CA
- Primary inoperable tumors due to local invasion
- Tumors that are > 1cm or have extra thyroidal disease (extra-capsular invasion, nodal spread, or mets)

134

Why does total thyroidectomy need to be performed for patients with papillary or follicular cell CA and mets for i-131 treatment?

Need to perform total thyroidectomy to facilitate uptake of i-131 to the metastatic lesions (otherwise all gets absorbed by the thyroid gland)

135

Side effects: i-131 (rare)

Sialoadenitis, GI symptoms, infertility, bone marrow suppression, parathyroid dysfunction, leukemia

136

Can help suppress TSH an slow metastatic disease; administered only after i-131 therapy has finished

Thyroxine

137

Define the arterial blood supply to the thyroid.

1. Superior thyroid artery (first branch off external carotid)
2. Inferior thyroid artery (branch of thyrocervical trunk) (IMA artery rare)

138

What is the venous drainage of the thyroid?

1. Superior thyroid vein
2. Middle thyroid vein
3. Inferior thyroid vein

139

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

Pyramidal lobe.

140

What percentage of patients have a pyramidal lobe?

~50%.

141

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

Anterior jugular veins.

142

Name the lymph node group around the pyramidal thyroid lobe.

Delphian lymph node group.

143

What is the thyroid isthmus?

Midline tissue border between the left and right thyroid lobes.

144

Which ligament connects the thyroid to the trachea?

Ligament of Berry

145

What is the IMA artery?

Small inferior artery to the thyroid from the aorta or innominate artery

146

What percentage of patients have a IMA artery?

~3%

147

Name the most posterior extension of the lateral thyroid lobes.

Tubercle of Zuckerkandl

148

Which paired nerves must be carefully identified during a thyroidectomy?

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.

149

What other nerve is at risk during a thyroidectomy and what are the symptoms?

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

150

What is TRH?

Thyrotropin-releasing hormone: released from hypothalamus, causes release of TSH

151

What is TSH?

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

152

What are the thyroid hormones?

T3 and T4

153

What is the most active form of thyroid hormone?

T3

154

What is a negative feedback loop?

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

155

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

Peripheral (eg, liver)

156

What is Synthroid (levothyroxine): T3 or T4?

T4

157

What is the half-life of Synthroid (levothyroxine)?

7 days

158

What do parafollicular cells secrete?

Calcitonin

159

What percentage of people have a thyroid nodule?

~ 5%

160

What is the differential diagnosis of a thyroid nodule?

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

161

Name three types of non thyroidal neck masses.

1. Inflammatory lesions (eg, absecess, lymphadenitis)
2. Congenital lesions (ie thyroglossal duct (midline), branchial cleft cyst (lateral)
3. Malignant lesions: lymphoma, mets, SCCa

162

What studies can be used to evaluate a thyroid nodule?

US - solid or cystic nodule
FNA
131-i: hot or cold nodule

163

What is the diagnostic test of choice for thyroid nodule?

FNA

164

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

~ 5%

165

What is meant by a hot vs cold nodule?

Nodule uptake of IV 131-i or 69-mT
- Hot: increased 131-i uptake -> functioning / hyper functioning nodule
- Cold: decreased 131-i uptake -> nonfunctioning nodule

166

What are the indications for a 123-i scintiscan?

1. Nodule with multiple "non diagnostic" FNAs with low TSH
2. Nodule with thyrotoxicosis and low TSH

167

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

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

168

History -> suggest thyroid CA

1. Neck radiation
2. Family history (thyroid cancer, MEN2)
3. Young age (especially children)
4. Male > female

169

Signs -> suggest thyroid CA

1. Single nodule
2. Cold nodule
3. Increased calcitonin levels
4. Lymphadenopathy
5. Hard, immobile nodule

170

Symptoms -> suggest thyroid CA

1. Voice change (vocal cord paralysis)
2. Dysphagia
3. Discomfort (in neck)
4. Rapid enlargement

171

What is the MCC thyroid enlargement?

Multinodular goiter

172

What are indications for surgery with multi nodular goiter?

Cosmetic deformity, compressive symptoms, cannot r/o cancer

173

What is Plummer's disease?

Toxic multinodular goiter

174

What % of cold thyroid nodules are malignant?

~ 25% in adults

175

What % of multi nodular masses are malignant?

~ 1%

176

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

Most experts would remove the nodule surgically (Because of the high risk of radiation)

177

What should be done with thyroid cyst aspirate?

Send to cytopathology

178

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

1. Papillary: 80%
2. Follicular: 10%
3. Medullary: 5%
4. Hurthle cell: 4%
5. Anaplastic: 1-2%

179

What are the s/s thyroid CA?

Mass / nodule, lymphadenopathy, most are euthyroid

180

What comprises the thyroid CA work up?

FNA, thyroid U/S, TSH, calcium level, CXR, +/- scintiscan 123-i

181

What oncogenes are associated with thyroid cancers?

Ras gene family and RET porto-oncogene.

182

What is papillary carcinoma's claim to fame?

MC thyroid cancer - 80% of all thyroid cancers

183

Environmental risk: papillary CA

radiation exposure

184

Average age: papillary CA

30-40 years

185

Sex distribution: papillary CA

Female > male - 2:1

186

Associated histologic findings: papillary CA

Psammoma bodies

187

Describe the route and spread - papillary CA

Most spread via lymphatics (cervical adenopathy); occurs slowly

188

papillary CA: i-131 uptake

Good uptake

189

What is the 10-year survival rate of papillary CA?

~ 95%

190

What is the treatment for

1. Thyroid lobectomy and isthmectomy
2. Near-total thyroidectomy
3. Total thyroidectomy

191

What is the treatment for papillary CA > 1.5 cm, bilateral, + cervical node mets, OR a h/o radiation exposure?

Total thyroidectomy

192

Does positive cervical nodes affect prognosis of papillary CA?

No!

193

What is the treatment for lateral palpable cervical lymph nodes in papillary CA?

Modified neck dissection (ipsilateral)

194

What is the treatment for central cervical lymph nodes of papillary CA?

Central neck dissection

195

What is a "lateral aberrant thyroid" in papillary cancer?

Misnomer - it is metastatic papillary carcinoma to a LN

196

What post op med should be administered in papillary CA?

Thyroid hormone replacement, to suppress TSH

197

What is the postoperative treatment option for papillary carcinoma?

Post op 131-i scan can locate residual tumor and distant mets that can be treated with ablative doses of 131-i.

198

What is the MC site of distant mets in papillary CA?

Pulmonary (lungs)

199

What are the "P's" of papillary CA?

Popular. Psammoma bodies. Palpable lymph nodes. Positive 131-i uptake. Positive prognosis. Postop 131-i scan. Pulmonary mets.

200

What percentage of thyroid cancers is follicular CA?

~ 10%

201

Describe the nodule consistency of follicular CA?

Rubbery, encapsulated

202

What is the route of spread of follicular CA??

Hematogenous, more aggressive than papillary adenocarcinoma

203

What is the male:female ratio of follicular CA?

1:3

204

131-i uptake follicular CA?

Good uptake

205

What is the overall 10-year survival rate follicular CA?

~ 55%

206

Can the diagnosis of follicular CA be made by FNA?

No; tissue structure is needed for the diagnosis of cancer.

207

What histologic findings describe malignancy in follicular CA?

Capsular or blood vessel incasion

208

What is the MC site of distant mets of follicular CA?

Bone

209

What is the treatment of follicular CA?

Total thyroidectomy

210

What is the post op treatment option of follicular CA?

Post op 131-i scan for diagnosis / treatment

211

What are the four F's of follicular cancer?

Far-away mets (spreads hematogenously)
Female (3:1 ratio)
FNA
Favorable prognosis

212

What is hurthle cell thyroid Ca?

Thyroid cancer of hurthle cells

213

What percentage of thyroid cancers is hurthle cell thyroid Ca?

~ 5%

214

What is the cell of origin of Hurthle cell?

Follicular cells

215

131-i uptake in hurthle cell ca?

No uptake

216

How is the diagnosis of hurthle cell ca made?

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

217

What is the route of metastasis of hurthle cell ca?

Lymphatic > hematogenous

218

What is the treatment of hurthle cell ca?

Total thyroidectomy

219

What is the 10-year survival rate of hurthle cell ca?

80%

220

What percentage of all thyroid cancers does medullary carcinoma comprise?

~ 5%

221

With what other conditions is medullary carcinoma associated?

MEN type 2; autosomal-dominant genetic transmission

222

Histology of medullary carcinoma?

Amyloid

223

What is the tumor marker of medullary carcinoma?

Calcitonin

224

What is the appropriate stimulation test for medullary carcinoma?

Pentagastrin (causes an increase in calcitonin)

225

Describe the route of spread of medullary carcinoma

Lymphatic and hematogenous distant mets

226

How is the diagnosis of medullary carcinoma made?

FNA

227

131-i uptake medullary carcinoma

Poor uptake

228

What is the associated genetic mutation of medullary carcinoma

RET proto-oncogene

229

What is the female/male ratio of medullary carcinoma?

Female > male; 1.5:1

230

What is the 10-year survival rate of medullary carcinoma?

80% without LN involvement. 45% with LN spread.

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What should all patients with medullary thyroid cancer also be screened for?

MEN2: pheochromocytoma, hyperparathyroidism

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If medullary carcinoma and pheochromocytoma are found, which one is operated on first?

Pheochromocytoma

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What is the treatment of medullary carcinoma?

Total thyroidectomy and median lymph node dissection. Modified neck dissection, if lateral cervical nodes are positive.

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What are the M's of medullary carcinoma?

MEN II
Amyloid
Median lymph node dissection
Modified neck dissection if lateral nodes are positive

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What is anaplastic carcinoma is also known as?

Undifferentiated carcinoma

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What is anaplastic carcinoma?

Undifferentiated cancer arising in ~ 75% of previously differentiated thyroid cancers (MC'ly, follicular carcinoma)

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What percentage of all thyroid cancers does anaplastic carcinoma comprise?

~ 2%

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What is the gender preference of anaplastic carcinoma?

Women > Men

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What are the associated histologic findings of anaplastic carcinoma?

Giant cells, spindle cells

240

131-i uptake of anaplastic carcinoma?

Very poor uptake

241

How is the diagnosis made of anaplastic carcinoma?

FNA (large tumor)

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What is the major differential diagnosis of anaplastic carcinoma?

Thyroid lymphoma (much better prognosis)

243

What is the treatment of the following disorders: small tumors of anaplastic carcinoma?

Total thyroidectomy + XRT / chemotherapy

244

What is the treatment of airway compromise of anaplastic carcinoma?

Debulking surgery and tracheostomy, XRT/chemotherapy

245

What is the prognosis of anaplastic carcinoma?

Dismal, because most patients are at stage IV at presentation (3% alive at 5 years)

246

What lab value must be followed postoperatively after a thyroidectomy?

Calcium decreased secondary to parathyroid damage; during lobectomy, the parathyroids must be spared and their blood supply protected; if blood supply is compromised intraoperatively, they can be autographed into the SCM or forearm

247

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

- Neck hematoma (remove sutures and clot at the bedside).
- Bilateral recurrent laryngeal nerve damage

248

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

Misnomer: it is papillary cancer of a lymph node from metastasis

249

What is the MCC hyperthyroidism?

Graves' disease

250

What is Graves' disease?

Diffuse goiter with hyperthyroidism, exophthalmos, and pretibial myxedema

251

What is the etiology of Graves'?

Caused by circulating antibodies that stimulate TSH receptor on follicular cells of the thyroid and cause deregulated production of thyroid hormones (i.e., hyperthyroidism)

252

What is the female: male ratio of graves' disease?

6:1

253

What specific physical finding is a/w Graves'?

Exophthalmos

254

How is the diagnosis made of Graves'?

Increased T3, T4, and anti-TSH receptor antibodies, decreasedTSH, global uptake of 131-i radionuclide

255

Name treatment option modalities for Graves' disease.

1. Medical blockade: iodide, propranolol, PTU, methimazole, Lugol's solution
2. Radioiodide ablation: most popular therapy
3. Surgical resection: bilateral subtotal thyroidectomy

256

What are the possible indications for surgical resection of Graves' disease?

Suspicious nodule; if patient is noncompliant or refractory to medicines, pregnant, a child, or if patient refuses radio iodide therapy.

257

What is the major complication of radio iodide or surgery for Graves' disease?

Hypothyroidism

258

What does PTU stand for?

Propylthiouracil

259

How does PTU work?

1. Inhibits incorporation of iodine into T4/T3 (by blocking peroxidase oxidation of iodine to iodine)
2. Inhibits peripheral conversion of T4 to T3

260

How does methimazole work?

Inhibits incorporation of iodine into T4/T3 only (by blocking peroxidase oxidation of iodine to iodine)

261

What is toxic multi nodular goiter?

Plummer's disease

262

What is toxic multi nodular goiter?

Multiple thyroid nodules with one or more nodules producing thyroid hormone, resulting in hyper functioning thyroid (hyperthyroidism or a "toxic" thyroid state)

263

What medication may bring on hyperthyrdoisim with a multi nodular goiter?

Amiodarone (or any iodine-containing medication / contrast)

264

How is the hyper functioning thyroid nodule localized?

131-i radionuclide scan

265

What is the treatment of toxic multi nodular goiter?

Surgically remove hyper functioning nodules with lobectomy or near total thyroidectomy

266

What is Pemberton's sign?

Large goiter causes plethora of head with raising of both arms.

267

What are the features of acute thyroiditis?

Painful, swollen thyroid, fever, overlying skin erythema, dysphagia

268

What is the cause of acute thyroiditis?

Bacteria (usually Streptococcus or Staphylococcus), usually caused by a thyroglossal fistula or anatomic variant

269

What is the treatment of acute thyroiditis?

Antibiotics, drainage of abscess, needle aspiration for culture, most patients need definitive surgery later to remove the fistula.

270

What are the features of subacute thyroiditis?

Glandular swelling, tenderness, often follows URI, elevated ESR

271

What is the cause of subacute thyroiditis?

Viral infection

272

What is De Quervain's thyroiditis?

Another name for subacute thyroiditis

273

How can the difference between the etiologies of acute and subacute thyroiditis be remembered?

A before S, B before V. (Acute before Subacute, Bacterial before Viral. (Acute: bacterial, Subacute: viral)

274

What are the common causative bacteria in acute suppurative thyroiditis?

Streptococcus or Staphylococcus

275

What are the two types of chronic thyroiditis?

1. Hashimoto's thyroiditis
2. Reidel's thyroidits

276

What are the features of Hashimoto's (chronic) thyroiditis?

Fine and rubbery gland, 95% in women, lymphocyte invasion.

277

What is the claim to fame of Hashimoto's disease?

MCC hypothyroidism in the US

278

What is the etiology of Hashimoto's disease?

Autoimmune

279

What lab tests should be performed to diagnose Hashimoto's disease?

Antithyroglublin and microsomal antibodies

280

What is the medical treatment for Hashimoto's thyroiditis?

Thyroid hormone replacement if hypothyroid (surgery is reserved for compressive symptoms and/or if cancer needs to be ruled out)

281

What is Riedel's thyroiditis?

Benign inflammatory thyroid enlargement with fibrosis of the thyroid. Patients present with painless, large thyroid. Fibrosis may involve surrounding tissues.

282

What is the treatment for Riedel's thyroiditis?

Surgical tracheal decompression, thyroid hormone replacement as needed - possibly steroids / tamoxifen if refractory.