thyroid disorders pt 2 Flashcards
1
Q
state of excessive levels of T3 and T4
A
Thyrotoxicosis
2
Q
increased state of thyroid function
A
Hyperthyroidism
3
Q
types of Hyperthyroidism
A
- Primary - Due to excessive release T3 and T4 by thyroid
- Secondary - Due to excessive release of TSH by pituitary
- Tertiary - Due to excessive release of TRH by hypothalamus
4
Q
thyrotoxicosis is MC in who? who has a higher incidence?
A
5x more common in women
Higher incidence in smokers
5
Q
MC cause of Thyrotoxicosis
A
Graves Disease - MC 60-80%
1. Autoantibodies bind TSH receptor in thyroid gland, = excessive thyroid function
- Thyroid-stimulating Ig (TSI) - (+) in 65% of cases
- May also see (+) anti-TPO (75%) and (+) anti-Tg (55%)
Often have (+) family hx of autoimmune thyroid disease
6
Q
MC onset of thyrotoxicosis
A
women ages 20-40
7
Q
Assists with diagnosis of Grave’s Disease
May be a follow-up to other abnormal thyroid function studies
A
Thyroid-Stimulating Ig (TSI)
AKA TSH receptor antibodies, TSHrAb
8
Q
Interfering Factors of Thyroid-Stimulating Ig (TSI)
A
Recent administration of radioactive iodine can interfere with results
Titers may not decline for up to 1 year after treatment
9
Q
high Thyroid-Stimulating Ig (TSI) means what?
A
Graves disease
10
Q
causes of Thyrotoxicosis
A
- Excessive Iodine
- Iodinated radiocontrast dye
- High-iodine foods (kelp, nori)
- Medications - potassium iodine, amiodarone,
iodinated topical antiseptics (povidone iodine)
— Amiodarone - 37% iodine by weight - 3% of patients taking the medication - Thyroiditis
- Infectious/subacute thyroiditis
- Silent/postpartum thyroiditis - Thyroid Nodules
- Toxic multinodular goiter
- Single toxic adenomas - Other causes
- Meds - chemotherapy and MS medications
- hCG - pregnancy, gestational trophoblastic disease, testicular cancer
— Causes cross-stimulation of TSH receptors
- Thyrotoxicosis factitia - intentional or accidental excessive ingestion of exogenous thyroid hormone
- Ectopic thyroid tissue - struma ovarii, metastatic thyroid cancer
- TSH hypersecretion
11
Q
symptoms of thyrotoxicosis
A
- General
- Fatigue and weakness
- Weight loss with increased appetite - Psych
- Nervousness/restlessness
- Hyperactivity/irritability - Cardio
- Palpitations/angina - MSK/Neuro
- Muscle cramps - GI/GU
- Polyuria
- Diarrhea - Endo/Reproductive
- Heat intolerance and sweating
- Oligomenorrhea
12
Q
signs of thyrotoxicosis
A
- General
- Thin body habitus - Psych
- Agitation, restlessness - Cardio
- Tachycardia
- Atrial fibrillation - MSK/Neuro
- Muscle weakness
- Hyperreflexia
- Osteoporosis
- Fine resting tremors - Endo/Reproductive
- Goiter/thyromegaly (if Graves, MNG) - Skin
- Warm, moist skin - Eyes
- Lid lag or lid retraction
13
Q
manifestations of graves disease
A
- Graves ophthalmopathy
- Thyroid acropachy
- Graves dermopathy
(pretibial myxedema)
14
Q
pt has
Upper eyelid retraction
Lid lag with downward gaze
“Staring” appearance
May see conjunctival edema and inflammation
what do they have?
A
Graves ophthalmopathy
15
Q
pt with
Digital clubbing
Swelling of fingers and toes
Periosteal reaction of extremity bones
what do they have?
A
Thyroid acropachy
16
Q
pt has
Erythematous, rough plaques
Lymphoid infiltration and glycosaminoglycans accumulation in affected skin
what do they have?
A
Graves dermopathy
(pretibial myxedema)
17
Q
Thyrotoxicosis - Clinical Presentation in Special Cases
A
Cardiopulmonary Manifestations
1. Forceful heartbeat
2. Exertional dyspnea
- Pulmonary HTN in 49% of patients
3. Abnormal conduction - Premature atrial contractions, sinus tachycardia, atrial tachycardia, atrial fibrillation
- More severe - men, elderly, pts with pre-existing heart disease
4. Can lead to cardiomyopathy
- Atrial fibrillation - may cause heart failure
5. Often partially or fully reversible with thyrotoxicosis tx!
Pregnancy
1. Pregnant women often have remission of Graves around the late second trimester
2. Untreated or undertreated thyrotoxicosis can cause pregnancy complications!
- Maternal - Preeclampsia-eclampsia, maternal heart failure, thyroid storm
- Fetal - miscarriage, preterm delivery, placental abruption, neonatal thyrotoxicosis
18
Q
basic diagnostic labs of thyrotoxicosis
A
- Thyroid Labs - Screen with serum TSH (+/- FT4)
- What change would we expect to see with her TSH and thyroid hormones? - Other Possible Lab Abnormalities
- Hypercalcemia, ↑ alk phos
- Anemia, ↓ granulocytes
19
Q
if Grave’s disease what labs would you see
A
65% chance of (+) TSI
75% chance of (+) anti-TPO
55% chance of (+) anti-Tg
20
Q
If Thyroiditis what would the labs look like?
A
Often have increased ESR
Typically have negative antithyroid antibodies
21
Q
Low serum thyroglobulin (Tg) levels is indicative of?
A
Thyrotoxicosis Factitia
22
Q
what is Radioactive Iodine (RAI) Uptake/Scanning
A
Measures thyroid metabolism by radioactive tracer iodine uptake
May help determine thyrotoxicosis etiology
23
Q
elevated uptake of Radioactive Iodine (RAI) Uptake/Scanning means?
A
Graves Disease, toxic solitary nodule, toxic multinodular goiter, type I amiodarone thyrotoxicosis
24
Q
decreased uptake of Radioactive Iodine (RAI) Uptake/Scanning means?
A
thyroiditis, iodine-induced thyrotoxicosis, type II amiodarone thyrotoxicosis
25
what does Radioactive Iodine (RAI) Uptake/Scanning NOT differentiate?
between cancer and other etiologies
26
Radioactive Iodine (RAI) Uptake/Scanning requires what, therefore avoid pregnant women
radiation
27
what imaging may help evaluate thyromegaly, nodules
Thyroid Ultrasound
28
what imaging can identify increased blood flow Limitations of thyroid US
Color flow Doppler sonography
- Dependent on operator skill and patient body habitus
- Does not delineate between benign and cancerous lesions
- Does not delineate metabolic activity of tissue
29
complications with thyrotoxicosis
1. _Ophthalmic_ - Severe ophthalmopathy = extraocular muscle entrapment, diplopia, optic nerve compression, and corneal drying with incomplete lid closure
2. _Cardiac_ - Arrhythmias and HF
3. _Pulmonary_ - Dyspnea, pulmonary hypertension
4. Other Complications
- _Calcium_ - Hypercalcemia, osteoporosis, nephrocalcinosis
- _Hypokalemic periodic paralysis_ - symmetric flaccid paralysis after IV dextrose, oral carbs, or vigorous exercise - in Asian or American Indian men
5. _Thyroid Storm_ - Severe, life-threatening thyrotoxicosis
30
____ is also associated with Graves disease (ophthalmic)
Ocular myasthenia gravis
31
tx for Ocular myasthenia gravis
steroid therapy
severe - radiation or surgery
32
tx for cardiac complications from thyrotoxicosis
(Arrhythmias and HF)
cardiac medications - BBs, digoxin, anticoagulation
33
what can trigger a thyroid storm
illness, RAI administration, thyroid surgery
34
manifestations of thyroid storm
thyrotoxicosis symptoms, but worse
Marked delirium
Severe tachycardia
Vomiting and diarrhea
Dehydration
Very high fever
35
tx for thyroid storm
1. Thiourea drug - Methimazole or PTU
- Inhibit oxidation of iodine, prohibiting thyroid hormone formation
2. Iodinated contrast agent - ipodate sodium or iopanoic acid
- Inhibit peripheral conversion of T4 to T3
3. Beta blocker - propranolol or atenolol
- Relieves symptoms (tachycardia, tremor, anxiety)
4. Hydrocortisone
- Avoidance of aspirin therapy
5. Definitive tx - radioactive iodine or surgery
36
Normal serum FT4 and T3 with low TSH
what type of Thyrotoxicosis
Subclinical Hyperthyroidism
37
manifestations of Subclinical Hyperthyroidism
_asx or mild hyperthyroid s/s_
- May have higher risk of known hyperthyroidism complications such as osteopenia/osteoporosis and cardiac arrhythmias
38
tx for subclinical hyperthyroidism
observation if no s/s
- Evaluate and Tx of Cause - if TSH <0.1 mIU/L, if symptomatic, or if high risk for complications
39
prognosis of subclinical hyperthyroidism
- 1-2% per year progress to symptomatic thyrotoxicosis
- If multinodular goiter - 5% per year progress
40
tx for Grave's disease
1. Beta Blockers - propranolol, atenolol
2. Iodinated Contrast Agents - iopanoic acid, ipodate sodium
3. Thiourea Drugs - methimazole, Propylthiouracil (PTU)
41
what medication
Improves tachycardia, palpitations, anxiety, tremor, etc.
Often given initially for s/s until antithyroid therapies have a chance to work
BBs
42
what medication
Block conversion of T4 to T3
Often given in severely symptomatic thyrotoxic patients
Efficacy wanes over time with continued use
Iodinated Contrast Agents
43
what drug
- inhibits production of thyroid hormone
- Useful in mild cases, elderly, young adults, pts who cannot have more definitive tx, and to prepare for RAI or surgery tx
- No permanent damage to thyroid
--- Lower chance of post-tx hypothyroidism
- Associated with SE of agranulocytosis and pancytopenia
Thiourea Drugs
44
which Thiourea Drug is preferred in most pts
Methimazole
45
which thiourea drug is preferred if first trimester or breastfeeding
Propylthiouracil (PTU)
46
MOA of Methimazole
inhibits organification of iodine, blocking formation of thyroid hormone
47
indications of Methimazole
General hyperthyroidism, hyperthyroidism due to Graves Disease
48
SE of Methimazole
1. greater risk of teratogenicity and goes more into breast milk than PTU
2. Derm - pruritus, rash, urticaria
3. MSK - joint pain
4. GI - abnormal taste, N/V, hepatotoxicity (less risk of hepatotoxicity than PTU)
5. Heme - agranulocytosis (greatest risk in first 2-3 months of tx)
49
how to monitor methimazole
thyroid labs; CBC; liver function tests
50
MOA of Propylthiouracil (PTU)
inhibits organification of iodine, blocking formation of thyroid hormone; also decreases peripheral tissue conversion of T4 to T3
51
indications of Propylthiouracil (PTU)
Hyperthyroidism
52
SE of Propylthiouracil (PTU)
1. Carries greater risk of hepatotoxicity than methimazole - has a **black box warning**
2. Derm - pruritus, rash, urticaria
3. MSK - joint pain
4. GI - abnormal taste, N/V, hepatotoxicity (higher risk than methimazole)
5. Heme - agranulocytosis (greatest risk in first 2-3 months of tx)
6. Reproductive - lower risk of teratogenicity and breast milk transmission
53
CI of PTU
hypersensitivity to rx; in Canada, breastfeeding is also a CI
54
how to monitor while on PTU
thyroid labs; CBC; liver function tests
55
definitive tx of grave's disease
**_destruction of overactive thyroid tissue_**
1. Radioactive Iodine (131I, RAI)
2. Surgery
56
which Grave's disease tx is
not safe in pregnancy or lactation
No increased risk of subsequent thyroid cancer or other cancers
Radioactive Iodine (131I, RAI)
57
which grave's disease tx is
for pregnant women, pts who do not want radioactive tx, or if suspicion of malignancy
Procedure of choice - total resection of lobe and subtotal resection of the other lobe
surgery
58
what drug can cause reduced efficacy of Radioactive Iodine (131I, RAI)
Methimazole
d/c at least 4 days prior
59
which tx of grave's disease may worsen ophthalmopathy? what should be given to tx that?
Radioactive Iodine (131I, RAI)
steroids
60
which drug is used to ensure patients are euthyroid at surgery
Thiourea drugs pre-op
61
complications with surgery for grave's disease tx
damage to recurrent laryngeal nerve, hypoparathyroidism
62
tx for toxic solitary nodule
may evaluate with FNA to rule out cancer
1. Symptomatic - BB + methimazole or PTU
- Keep TSH slightly suppressed to inhibit further growth of nodule
2. Surgery - if pt is <40 y/o or in healthy older patients
- RAI may be given to patients who are not surgical candidates
63
tx for Amiodarone-Induced
1. _Sx_ - **BB + methimazole**
- Adjunct therapy of iodinated contrast agent if needed
2. D/C amiodarone does _not_ have a significant impact for several months
3. _Refractory cases_ - surgery
64
tx for Toxic Multinodular Goiter
1. _Sx_ - **BB + methimazole or PTU**
- 95% recurrence if thiourea drug is discontinued
2. _Surgery_ - definitive tx; thyroidectomy
- Relieves feeling of pressure and visible external swelling
- Allows for evaluation and removal of potential occult cancers
3. RAI - for pts who are not surgical candidates
65
tx for Thyroiditis
1. Thioureas - ineffective; thyroid hormone production is low
2. Symptomatic - BB therapy; iodinated contrast agents if severe
- NSAIDs or opioids as adjunct for pain management
66
MC thyroid disorder in the US
**Hashimoto (Autoimmune) Thyroiditis**
- 6x MC in _women_
- _Risks_ - head-neck radiation, + family hx, hepatitis C, iodine deficiency
67
what causes hashimoto's
Associated with (+) anti-TPO and (+) anti-Tg
- May transiently cause hyperthyroidism (“Hashitoxicosis”)
- May resolve, but typically progresses to hypothyroidism over time
68
what are the "silent" thyroiditis
1. **_Painless postpartum thyroiditis_** - occurs after delivery in ~7% of women
- Transient hyperthyroidism followed by transient hypothyroidism
- 70% chance of recurrence in subsequent pregnancies
- Associated with thyroid autoantibodies, particularly (+) anti-TPO
2. **_Painless sporadic thyroiditis_** - subacute Hashimoto thyroiditis
- Similar to painless postpartum thyroiditis, but not associated with pregnancy
69
cause of subacute thyroiditis
1. believed to be due to a _viral infection_ (often URI)
2. AKA - de Quervain thyroiditis, granulomatous thyroiditis, giant cell thyroiditis
3. Up to 5% of clinical thyroid disease
4. MC - young and middle-aged women, summer
70
cause of suppurative (infectious) thyroiditis
- _nonviral_ thyroid gland infection
- More common in immunosuppressed > non-immunosuppressed
71
cause of Riedel thyroiditis
1. rarest thyroiditis; often due to _systemic fibrosis_
2. AKA - Riedel struma, woody or ligneous thyroiditis, invasive fibrous thyroiditis
3. MC - middle-aged or elderly women
72
clinical presentation of hashimoto's
1. diffusely enlarged, firm, finely nodular thyroid
2. Usually no pain or tenderness associated; may have “tight” feeling in neck
3. Often complain of hypothyroid symptoms
4. May be more prone to depression and fatigue even once thyroid labs WNL
73
clinical presentation of painless postpartum thyroiditis
1. may have some thyroid enlargement
2. Transient hyperthyroidism beginning 1-6 months after delivery
3. Hyperthyroidism lasts x 1-2 months
4. Hypothyroidism tends to follow and lasts for a few months
74
clinical presentation of painless sporadic thyroiditis
1. 50% may have a small, nontender goiter
2. Transient hyperthyroidism x 1-2 months
3. Transient hypothyroidism for a few months
75
clinical presentation of subacute thyroiditis
**_acute enlargement of thyroid gland_**
1. pain and dysphagia MC
- Pain often referred to ear or jaw
2. associated malaise and low-grade fever
3. hx of recent URI
4. thyrotoxicosis for ~4 wks, then hypothyroidism x 4-6 months
- Most completely recover; some have persistent hypothyroidism
76
clinical presentation of suppurative thyroiditis
1. severe pain, tenderness, redness, and fluctuance associated with the thyroid gland
2. Often have associated fever
3. Typically have hx of immunosuppression
77
clinical presentation of Riedel thyroiditis
1. asymmetric, stony, adherent thyroid gland
2. May have associated dysphagia, dyspnea, pain, hoarseness
78
labs for Hashimoto thyroiditis
**anti-TPO and/or anti-Tg antibodies**
- Antibodies helpful for _diagnosis, but *not* disease monitoring_
- May have thyroid labs consistent with hyper- or hypothyroidism
- may have serum antibodies consistent with celiac disease
79
labs for Subacute thyroiditis
- elevated ESR levels
- low antithyroid antibody titers
- May have thyroid labs consistent with hyper- or hypothyroidism
80
labs for Suppurative thyroiditis
- **Elevated ESR and leukocytes**
- Often normal thyroid function studies and antithyroid antibodies
81
labs for Riedel thyroiditis
May have normal thyroid labs, or signs of hyper- or hypothyroidism
82
Use of Anti-TPO labs
1. Assist with diagnosis of autoimmune thyroid disease
- esp Hashimoto Thyroiditis (~95% of pts)
- can be with Graves Disease (~70%) and other conditions
83
interpretation of high anti-TPO
1. **_Autoimmune thyroid disease_** - Hashimoto, Graves
2. Other thyroid conditions - cancer, goiter
3. Other AI conditions - RA, pernicious anemia, rheumatoid-collagen disease
84
interpretation of high anti-Tg
1. **_Autoimmune thyroid disease_** - Hashimoto thyroiditis, Graves disease
2. Other thyroid conditions - cancer, goiter
3. Other AI conditions - RA, pernicious anemia, rheumatoid-collagen disease
84
how would thyroid ultrasounds look like/be helpful?
1. Hashimoto thyroiditis - diffuse heterogeneous texture
2. Suppurative - Can identify presence of abscess
3. Hyperthyroidism - can help distinguish cause
- Graves Disease - increased vascularity
- Thyroiditis - normal or decreased vascularity
85
how would RAI uptake scanning be helpful/look like?
1. Hyperthyroidism - can help distinguish Graves from thyroiditis
- Graves Disease - increased RAI uptake
- Thyroiditis - typically has low RAI uptake
86
FNA biopsy can be helpful in what thyroiditis conditions
1. Hashimoto thyroiditis - Nodules carry an 8% chance of cancer
2. Suppurative - FNA biopsy with Gram stain and culture required
87
complications with thyroiditis
1. Abnormal thyroid function
- Thyrotoxicosis and thyroid storm
- Hypothyroidism - temporary or permanent
2. Higher risk of depression
3. Pressure on local neck structures
4. Hashimoto - Higher risk of 1st trimester spontaneous miscarriage (if untreated)
5. Suppurative - Abscess and/or chronic sinus tract formation
6. Cancer - Associated with chronic thyroiditis
88
management for thyroiditis (all conditions)
1. Hashimoto - observe (asx and minimally enlarged or normal size thyroid gland)
- Hypothyroidism - replacement with levothyroxine
- Large gland/goiter - may try levothyroxine suppressive therapy
2. Subacute thyroiditis - high-dose aspirin/ NSAIDs are tx of choice
- +/- corticosteroids for severe or refractory cases
- BB can be helpful for acute symptoms
- Severe thyrotoxicosis - iodinated contrast agents
3. Suppurative thyroiditis - antibiotics, surgical drainage of abscess
4. Riedel thyroiditis - tamoxifen and/or steroid therapy
- Surgery for decompression if needed
89
State of abnormal thyroid function studies in the setting of severe nonthyroidal illness
Sick Euthyroid Syndrome
Often no hx of thyroid gland or HPT axis dysfunction
90
cause of sick euthyroid syndrome
_many_ - maybe due to cytokines, esp **IL-6**
- Sepsis
- Starvation/anorexia
- Burns
- CV, renal, pulmonary, GI, liver disease
- Trauma
- Surgery
- Cancer
91
what would labs look like for sick euthyroid syndrome?
varies in TSH, T3, T4, rT3, and FT4
depends on severity and underlying cause
92
pathophys of euthyroid syndrome?
**_impaired deiodination of T4 to T3_**
- Decreased clearance of reverse T3
- Cytokine-based inhibition of thyroid hormone production
- Impaired accuracy of thyroid labs in severe illness
93
management for sick euthyroid syndrome
_Observation_ without administration of thyroid hormone
- UNLESS pt has hx of pre-existing hypothyroidism or clinical s/s of hypothyroidism
94
prevalence of Thyroid Nodules/Goiter
1. Most nodules (≥ 1 cm) are benign (87%)
2. MC - iodine-deficient areas, increased age
3. Non-palpable nodules - 30% of pts on US; 60% on autopsy
4. Multinodular Goiter - about 50% of palpable nodules are actually MNG
95
thyroid function of thyroid nodules/goiter are ?
euthyroid
Higher rates of hypothyroidism or hyperthyroidism than avg pt
96
what % of palpable thyroid nodules is cancer? what increases the risk?
1. 10%
2. _Radiation_ - increased risk with hx of head/neck or total body radiation
3. _Family Hx_ - increased risk with (+) family hx of thyroid cancer
4. _Characteristics_ - increased risk with:
- Large nodule(s)
- Adherence to local structures
- Hoarseness or vocal cord paralysis
- Lymphadenopathy
97
s/s of small, solitary nodules
typically asx
May be incidentally found on exam/imaging
98
s/s of large multinodular goiters
1. may see swelling, hoarseness, dysphagia
- Retrosternal - dyspnea, facial erythema, jugular vein distension
99
s/s of abnormal thyroid function
1. may have s/s of hyper- or hypothyroidism
- _Hypothyroidism_ - Hashimoto, iodine deficiency, some nontoxic multinodular goiters, some simple goiters
- _Hyperthyroidism_ - Graves, toxic nodular goiter, subacute thyroiditis, differentiated thyroid cancer, solitary hyperfunctioning nodules
- Euthyroidism - some nontoxic multinodular goiters, some simple goiters
100
what diagnostic testing are you getting for thyroid nodules/goiter?
1. TSH - for all pts found to have a nodule/ goiter
- +/- FT4, autoimmune labs
2. Imaging
- Thyroid US
- RAI uptake
- CT Scan
3. Fine-Needle Aspiration Biopsy (FNA Biopsy)
101
during thyroid US for a nodule/goiter, what features make it more concerning?
1. Concerning Features
2. irregular margins
3. solid lesions
4. heterogeneous texture
5. abnormal vascularity
6. microcalcifications
7. larger nodules (>1 cm)
102
what diagnostic testing evaluates size and characteristics of nodule, and if nodule is part of MNG or solitary
thyroid US
103
what diagnostic testing evaluates hyperfunctioning thyroid tissue
RAI Uptake
104
what diagnostic testing is helpful to delineate very large nodules or MNG, degree of extension into mediastinum, and presence of tracheal compression
CT scan
105
a RAI uptake of an nodule is "cold"
what does this mean?
hypofunctioning/lower iodine intake
higher cancer risk
106
a RAI uptake of a nodule is "hot"
what does this mean?
hyperfunctioning/high iodine intake
lower cancer risk
107
what diagnostic testing is most commonly used to evaluate thyroid nodules for malignancy
FNA biopsy
Can be done w/ pts on anticoagulation or ASA
Uses US guidance
108
biopsy of thyroid nodule is indicated if:
1. +1 cm and suspicious appearance (irregular margins, microcalcifications)
2. +2 cm
3. Associated cervical LAN
4. Nodule is growing
109
what makes a nodule a low index of suspicion
1. Hx
- Family history of goiter
- Residence in area of endemic goiter
2. physical characteristics
- Older patient
- Female
- Soft nodule
- Smaller size (<1 cm)
- Multinodular goiter
3. Serum factors
- High titer of thyroid antibodies, especially anti-TPO
4. FNA biopsy
- Colloid nodule or adenoma
5. Imaging
- Hot nodule on RAI
- Cystic lesion on US
- Shell-like calcification
6. Response to LT4 therapy
- Regression after 6 months of tx
110
what makes a nodule have high index of suspicion
1. hx
- Previous radiation of head/neck/chest
- Hoarseness
2. physical characteristics
- Younger patients or pediatric
- Male
- Firm or hard nodule
- Large nodule (>2 cm)
- Solitary nodule
- Vocal cord paralysis
- Enlarged LN
3. serum factors
- Elevated calcitonin or CEA
4. serum factors
- Papillary carcinoma
- Follicular lesion
- Medullary or anaplastic carcinoma
5. FNA biopsy
- Cold nodule on RAI
- Solid lesion on US
- Punctate calcification
6. response to LT4 therapy
- Increase in size
111
management for thyroid nodule/goiter
1. _General f/u_ - regular palpation and US imaging
- Q 6 months initially, then yearly
- Avoidance of excessive iodine intake
2. _LT4 Suppression_ - if nodule >2 cm and normal or high TSH
- Nodules rarely shrink >50% from original size
- Reduces emergence of new nodules
- _Risks_ - heart disease exacerbation, osteoporosis, hyperthyroidism
3. _Thiourea drugs +/- BB_ - if s/s of thyrotoxicosis
4. _Surgery_ - cancer, hyperfunctioning nodules, toxic MNG
5. _Ethanol injection_ - shrinkage of benign nodules
6. _RAI therapy_ - toxic thyroid adenomas, toxic MNG, Graves
- Shrinks nodules by up to 60%
- _Risks_ - hypothyroidism
112
thyroid cancer is MC in who?
- women (3:1)
- Increasing incidence with age
- MC endocrine cancer
- Most remain microscopic and indolent
113
1st and 2nd MC thyroid cancer?
Papillary Thyroid Carcinoma
Follicular Thyroid Carcinoma
114
characteristics of papillary thyroid carcinoma
1. Usually presents as a single thyroid nodule
2. Least aggressive form of thyroid cancer
- Slow-growing, often remain confined to thyroid/regional lymph nodes
- Best survival rates of any form of thyroid cancer
3. can be autosomal dominant trait
4. not much radioactive iodine uptake
115
which thyroid cancer is most likely to metastasize to distant sites
High level of iodine uptake - RAI scanning and treatment
Follicular Thyroid Carcinoma
116
which thyroid cancer
Can secrete calcitonin, prostaglandins, 5HT, ACTH, CRH
Often have early local metastases at time of diagnosis
Does not have good iodine uptake
medullary thyroid carcinoma
117
which thyroid cancer is the most aggressive thyroid carcinoma; worst survival
Anaplastic Thyroid Carcinoma
Classic - rapidly enlarging mass in MNG
Does not have good iodine uptake
118
presentation of thyroid cancer
1. PE - palpable, firm, nontender thyroid nodule or mass
2. Symptoms - often asx
- neck discomfort, dysphagia, hoarseness
- sometimes symptoms of hyper- or hypothyroidism
3. Metastasis - presenting s/s in about 3% of cases
- LN involvement in ~15% of adults and ~60% of children
- M/C sites - local LN, lungs, bone
4. Anaplastic - more likely to have s/s of metastasis, local invasion
5. Medullary - flushing and diarrhea (30%)
- Cushing-like symptoms (Rare)
119
diagnostic labs for thyroid cancer
1. Hyperthyroidism - can be in _follicular_ thyroid carcinoma
2. Serum thyroglobulin - elevated in _metastatic papillary_ and _follicular CA_
- Limitations - invalid if anti-Tg present; may be falsely ↑ in thyroiditis
3. Serum calcitonin - elevated in _medullary_ thyroid carcinoma
- Limitations - also high in thyroiditis, pregnancy, azotemia, hypercalcemia, other cancers
- Most useful to dx if very high levels or serially increasing levels
4. Serum CEA - elevated in _medullary_ thyroid carcinoma
- Limitations - also elevated in other cancers
- Can be used as an adjunct to help evaluate medullary thyroid carcinoma
120
uses for Tg lab
Assist with evaluating extent of papillary and follicular thyroid cancers, their prognosis, and their response to treatment
- Steadily rising Tg levels can help identify tumor recurrence
121
interfering factors of Tg
1. Elevated in benign conditions (thyroiditis, post-thyroid exam)
2. Thyroid HRT - suppress residual or metastatic thyroid tissue = falsely low Tg levels
3. Anti-Tg antibodies - false readings
122
interpretation of high Tg
1. Cancer - papillary or follicular thyroid cancer
2. Others - thyroiditis, thyroid trauma or recent examination
123
uses for calcitonin labs
1. for medullary thyroid carcinoma - evaluate extent of CA, response to tx
- Secreted by parafollicular cells of thyroid gland
- Normally stimulated by elevated serum calcium levels
- May help screen patients with (+) family hx of medullary thyroid carcinoma
124
interfering factors of calcitonin labs
1. Elevated
- pregnancy and neonates
- meds - calcium, oral contraceptives
125
interpretation of high calcitonin
1. **Medullary thyroid carcinoma**
2. _Non-cancer thyroid disorders_ - parafollicular cell hyperplasia, thyroiditis
3. _Other cancers_ - breast, pancreatic, lung
4. _Others_ - hyperparathyroidism, cirrhosis, pernicious anemia
126
uses for CEA lab
AKA: carcinoembryonic antigen
1. Assist with evaluating extent of certain cancers, and response to tx
- Steadily rising CEA levels can help identify tumor recurrence
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interfering factors of CEA
1. Elevated in smokers and due to many noncancerous dx (e.g. IBD, cirrhosis)
2. Not all cancers in target tissues produce CEA
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interpretation of high CEA
1. Cancer - GI, breast, lung, pancreatic, hepatobiliary, medullary thyroid
2. Others - inflammation, cirrhosis, peptic ulcer
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diagnostic imaging for thyroid cancer
1. Thyroid US - Helpful for determining size and location of mass
- More sensitive > CT/MRI for evaluating neck metastases
2. RAI Scan - Can use after thyroidectomy to do whole-body scans
- May reveal presence of metastatic tissue
- Not all thyroid cancers concentrate iodine well!
3. CT/MRI - Can help evaluate distant metastases (lung, liver, bone) or help delineate retrosternal masses
4. PET Scanning - Helpful for detecting mets not visible on RAI scanning
- Lacks specificity for thyroid cancer; expensive
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what is the papillary or follicular Ca staging
undifferentiated or anaplastic carcinomas are ALL stage IV
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management for thyroid cancer
1. **_Surgery_**
- _>1 cm mass known cancer_ = total thyroidectomy + cervical LN dissection
- _<1 cm mass known cancer_ - may consider lobectomy
--- well-differentiated, pt is young (< 45), no LN involvement seen on US, and no hx of risk factors such as radiation exposure
- _<4 cm indeterminate lesion_ - lobectomy (+/- later thyroidectomy)
- _>4 cm indeterminate lesion_ - total thyroidectomy
2. _Thyroxine Suppression_ - For differentiated thyroid cancers
- Must monitor thyroid labs; consider periodic bone density screening
3. _RAI Therapy_ - For differentiated thyroid cancers
- Can be done post-op or for pt who cannot have surgery
- _CI_ - pregnant or nursing, lacking childcare
- Pts must take a low-iodine diet for 2 wks before starting tx
- *Not helpful with undifferentiated cancers*
4. _Chemotherapy_ - for aggressive differentiated cancers
5. Anaplastic Thyroid Carcinoma - local resection and radiation
- Unresponsive to RAI and most chemotherapies
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Complications of Surgery
Laryngeal nerve palsy or permanent injury, hypoparathyroidism, airway swelling, bleeding, infection
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f/u for thyroid cancer
1. Recurrence - Most differentiated cancers recur within 5-10 years after tx
2. Monitoring - At least yearly thyroid US; thyroglobulin (if appropriate)
- Must monitor thyroid function studies to ensure adequate hormone levels
- TSH - Should be suppressed
- RAI Scan - May be ordered if cancer was well-differentiated
3. Prognosis - 10-yr survival rates
- >90% with papillary and follicular thyroid carcinomas
- ~78% with medullary thyroid carcinoma
- ~7% with anaplastic thyroid carcinoma
