Thyroid Disorders - Exam 3 Flashcards
TRH stands for ____ and comes from the _____. TSH stands for _____ and comes from the ______
Thyrotropin Releasing Hormone-> hypothalamus
Thyroid Stimulating Hormone -> Ant Pit
Describe the HPT axis in simplied terms
When there is no thyroid present, T3/T4 levels will _____ and TSH/TRH levels will _____
T3/T4 will decrease
TSH/TRH will increase
What will a pt with hyperthyroidism, ther T3/T4 levels will be ______ and TSH/TRH will be ______
T3/T4 will be increased
TSH/TRH will be decreased
A pt with hypothyroidism, their T3/T4 levels will be _____ and TSH/TRH levels will be ______.
T3/T4 will be decreased
TSH/TRH will be increased
_____ large glycoprotein synthesized by follicular cells of the thyroid; released into the colloid. _____ element actively absorbed by the thyroid for hormone synthesis
thyroglobulin
iodine aka no iodine no T3/T4 because it cannot be sythesized
____ enzyme; helps process iodine for use by thyroid ~1 mg/week requirement. Commonly added to table salt
Thyroid Peroxidase (TPO)
What is the difference between T3 and T4?
the number of iodine groups attached
When thyroid hormones are needed organified Tg (with attached T3/T4 molecules) is absorbed via
____ into the thyroid cells
pinocytic vesicles
Once in the blood, 99% of T3 and T4 bind immediately with _____ synthesized by the _____. ______ primary binding protein (80% of T3/T4)
plasma proteins
liver
Thyroxine-binding globulin (TBG) -
Most T4, once absorbed by _____, is converted to T3 by _____
tissues
deiodinases
_____ is metabolically active and is less stable, aka more easily unbound. ____ is more balanced and harder to unbind. What form is the storage form? ____ binds to the receptors with 10-15x more affinity
T3
T4
T4
T3
What would happen to T3/T4 if someone was deficient in TBG, but otherwise metabolically normal? What about to their free T3/T4? TSH/TRH?
total T3/T4 would decrease
Free T3/4 would be normal
TSH/TSH levels would be normal
Estrogen increases the levels of TBG. If someone had high estrogen levels (e.g. pregnancy, contraception), what would happen to their total T3/4? Free T3/T4? and TSH/TRH?
TOTAL T3/4 would increase
Free T3/4: normal
TSH/TRH: normal
What symptoms would you expect to see on a pt with elevated rT3?
hypothyroid s/s
_____ enzyme helps turn T4 into T3?
iodinase
What are some physiologic effects of thyroid on metabolism?
-Growth: especially of skeleton and brain
-Carb metabolism
-Fat metabolism: burns fat, decreases cholesterol, decreases fat stores
-Vitamin metabolism: increases baseline needs for vitamins
-Basal metabolic rate: hyper 60-100% increase. Hypo: up to 50% decrease
-body weight: help to decrease/maintain healthy body weight
What physiologic effects does the thyroid have on the organ systems?
-increased blood flow to tissues
-increased cardiac output
-increased heart rate
-increase heart strength with SLIGHT increase in thyroid hormone
- excitatory/depressive on nerve stimulation
- muscle weakness/sluggishness
-increased breathing rate/depth
- increase hormones secretion from other endocrine glands
What is the effect on the heart of a major increase in thyroid hormone?
weakened heart due to long-term and excessive protein catabolism
**Light periods can indicate _____. Heavy periods can indicate _____
light: can be hyper or hypo
**heavy: HYPO only!
What lab tests make up a thyroid panel?
Thyroid Stimulating Hormone - TSH
Triiodothyronine (total) - T3
Thyroxine (total) - T4
Free Thyroxine Index (unbound) - Free T4 or FT4
What are some interfering factors for TSH lab? What about the time of the day?
severe illness, NSAIDs (very protein bound)
time of the day (TSH is low in the AM and highest in the PM)
a high TSH indicates _____ or _____. _____ T3/4
a low TSH indicates ______. _____ T3/4
hypothyroidism or not enough thyroid meds. Not enough T3/4
primary hyperthyroidism. too much T3/4
primary hyperthyroidism has to due with the _____. Secondary is _____. Tertiary is _____-
thyroid itself
pituitary gland
hypothalamus
What are interfering factors of T3/T4? Does this indicate total or free?
estrogen meds
protein bound drugs )NSAIDs, phenytoin, androgens, lithium)
total unless it specifically says FREE
What is the interfering factor of FREE T3/4 lab?
Neonates have higher levels of FT4; typically screened using total T4
Why would you want to order a free T3/T4?
What thyroid labs does Professor Jensen recommend you order together?
Helps reduce confounding factor of serum protein levels
TSH and Free T4
What does an elevated T3, T4, Free T3, and Free T4 indicate? What does low indicate?
Excess amounts of thyroid hormone
Hyperthyroid states
Acute thyroiditis
Excess dosing of thyroid meds
Not enough thyroid hormone
Low T3/Free T3: decreased conversion of T3 aka liver disease or severe illness
Low T4/Free T4: pt is on T3 medication only
When is TBG used? Where is it released from?
Evaluation of abnormal total T3 or total T4 levels
Can help determine if patient is truly hypo/hyperthyroid versus just having abnormal levels of bound/unbound T3/T4
liver
What does elevated TBG indicate? low TBG?
elevated: elevated estrogen or infectious hepatitis
low: low proteins, ovarian failure, elevated testosterone levels, major stress
When is the TRH stimulation test used? What are some interfering exaggerated factors? diminished factors?
Assessment of pituitary response to TRH
Can help differentiate etiology of hypothyroidism
Can help evaluate degree of pituitary suppression in hyperthyroid pts
exaggerated in women and pregnancy
diminished in the elderly and in pts with MDD
What is a normal TRH stimulation test look like? Secondary hypo? tertiary? Hyper?
2x increase in baseline TSH within 30 minutes of TRH IV bolus
May also be seen in hypothyroidism due to severe illness
secondary: no increase in TSH
tertiary: delayed increase in baseline TSH 60-120 minutes
Hyper: Blunted TSH response due to maximal pituitary suppression by T3/T4
What are the pt stats for hypothyroidism? _____ is the leading cause worldwide. _____ is resource-rich countries
Roughly 1% of US patients - 5% of pts >60 y/o
5-8x more common in women
iodine deficiency
Hashimoto thyroiditis
What are the causes of primary, secondary and tertiary hypothyroidism?
Primary - Due to failure of thyroid to release T3 and T4
Secondary - Due to failure of pituitary to release TSH
Tertiary - Due to failure of hypothalamus to release TRH
What two medications are associated with hypothyroidism?
Amiodarone and Lithium
Fatigue
weight gain
dry skin
hair loss
constipation
poor appetite
cognitive impairment
cold intolerance
What am I?
______ is puffiness of face, hands and feet
hypothyroidism
myxedema
Hypothyroidism, TSH will be _____ and Free T4 to be _____. What other lab abnormalities would you expect?
TSH will be increased and Free T4 will be decreased
anemia, lipid abnormalities, hyponatremia (due to retaining fluid), hypoglycemia, elevated prolactin
If Hashimoto’s Thyroiditis what two antibody tests are possible to be positive. Which one is more likely to be positive?
90-95% chance of (+) anti-thyroid peroxidase antibody (anti-TPO)
70% chance of (+) anti-thyroglobulin antibody (anti-Tg)
When is imaging considered on a pt with hypothyroidism? What is the tool of choice? What other findings are possible? What do they indicate?
Consider if thyromegaly or thyroid nodule noted on exam
Thyroid Ultrasonography - noninvasive, relatively inexpensive
Enlarged thymus - possible if autoimmune thyroiditis is present
Enlarged pituitary - possible if hyperplasia of TSH-secreting cells occurs
What are some common complications of hypothryoidism?
CVD
adrenal disease
infertility
increased risk of bacterial pneumonia
increased risk of megacolon
_____ severe, life-threatening hypothyroidism. Often triggered by infection, illness, cold exposure, or drug use. What is the classic pt?
Myxedema Crisis
elderly women who have a stroke or stop taking thyroid meds
hypothermia
hypotension
hypoventilation
hyponatremia
hypoglycemia
cognitive impairment
mild confusion to coma
may see rhabdomyolysis and AKI
What am I?
What is the tx?
Myxedema Crisis
IV levothyroxine (LT4) therapy (if coma, add on IV T3)
Supportive care: warming blankets, intubation, tx of underlying cause
How do you define subclinical hypothryroidism? What is the MC pt type? How does it present? What is the tx?
Normal serum FT4 with TSH above reference range
MC in elderly (>65 y/o) pts - up to 13%
asymptomatic or mild hypothyroid s/s
observation if no s/s. May do trial of LT4 if symptomatic
1/3 of cases resolve spontaneously within 2 years
What is the first line tx for hypothyroidism? What do you need to screen for before starting? **What are threed important education points?
levothyroxine
valuate clinically for adrenal insufficiency/angina before start
- need to take at the same time every day on an empty stomach with a sip of water
- diff manufacturers make blood levels differ slightly so I need to know if you tablet changes
- peak response is usually seen in 4 weeks
Name some instances that you would need to increase the thyroid medication. What are the two major ones?
Medications - many anticonvulsants, sertraline, bile acid-binding resins, PPIs
**Increased estrogen - pregnancy, estrogen-containing medications
GI Disorders - celiac disease, IBD, lactose intolerance, gastritis
**Weight gain - over 10% body weight aka the heavier the person, the more medication they need to take
Name some instances that you would need to decrease the thyroid medication. What are the two major ones?
**Decreased estrogen - cessation of estrogenic meds, postpartum, post-oophorectomy
Increased androgen - starting testosterone therapy
**Weight loss - over 10% body weight
What is the BBW for all thyroid hormones?
All thyroid hormone replacement therapies carry a black box warning against the use of thyroid hormone replacement as a treatment for obesity.
**When a pt who has already been dx with hypothryroidism has an elevated TSH, what is the first question you should ask?
Verify how patient is taking medication!
If a hypothyroid pt has a hx of CAD or atrial fibrillation, where does their TSH level need to fall?
May need high-normal TSH if pt has history of CAD or atrial fibrillation
What would you do if a hypo pt has a normal TSH but is still symptomatic?
May consider free T3/T4 levels to evaluate adequacy of therapy
May consider T3 supplement or changing to combination T3/T4 (controversial)
If a hypo pt has a low TSH, what are you thinking?
too much thyroid meds
other medications: NSAIDs, opioids, CCBs, steroids
What does a suppressed TSH put you at risk for?
risk of atrial fibrillation, osteoporosis
What is the recommended starting dose for levothyroxine? What is the titration recommendations?
25-75 mcg daily OR 1.6 mcg/kg; titrate every 4-6 weeks to euthyroid status
first line is Levothyroxine!!
What are the SE of levothyroxine? What are the monitoring recommendations?
s/s of hyperthyroidism
TSH Q 4-6 wks after start/dose changes, then Q 6-12 mo
What is second line for hypothyroidism?
Liothyronine (LT3)
all SE, dose and monitoring are the same at levothyroxine
______ is a 1/4 ratio of T4/T3, made from beef or pork. What is the grain to mcg equivalent? What is the titration recommendation?
Desiccated Thyroid: 2nd line
65 mg (1 grain) = ~88-100 mcg of levothyroxine
titrate every 6 weeks to euthyroid status
______ state of excessive levels of T3 and T4.
_____ increased state of thyroid function
Thyrotoxicosis
Hyperthyroidism
What are the pts stats for Thyrotoxicosis?
Roughly 1% of US patients - 5% of women >60 y/o
5x more common in women
Higher incidence in smokers
_____ is the MC cause of thyrotoxicosis. What antibodies are commonly found? Which on is unique to this dz?
Graves Disease
**Thyroid-stimulating Ig (TSI) - (+) in 65% of cases
May also see (+) anti-TPO (75%) and (+) anti-Tg (55%)
Who is the MC pt type with Graves dz?
MC onset - women ages 20-40
When trying to confirm dx of Graves disease you would want to order _____. What will the result be? what are some interfering factors?
Thyroid-Stimulating Ig (TSI)
will be high in Graves dz
Recent administration of radioactive iodine can interfere with results
Titers may not decline for up to 1 year after treatment
What are some causes of thyrotoxicosis?
excessive iodine
thyroiditis
thyroid nodules
meds
hCG
Thyrotoxicosis factitia
Ectopic thyroid tissue
TSH hypersecretion
What are some causes of excessive iodine? What is the major one?
Iodinated radiocontrast dye
High-iodine foods (kelp, nori)
Medications: potassium iodine, **amiodarone, iodinated topical antiseptics (povidone iodine)
_____ intentional or accidental excessive ingestion of exogenous thyroid hormone
Thyrotoxicosis factitia
Fatigue
weight loss
increased appetite
nervousness
palpitations
polyuria
diarrhea
heat intolerance and sweating
What am I?
Thyrotoxicosis
What are the 3 clinical manifestations of Graves disease?
Graves ophthalmopathy (bulging eyes due to enlargement of extraocular muscles)
Graves dermopathy (pretibial myxedema) on the shins
Thyroid acropachy (clubbing of the fingers and toes)
What are some cardiopulmonary manifestations of thyrotoxicosis?
forceful heartbeat
exertional dyspnea and pulmonary HTN
abnormally fast heart rhythms
can lead to cardiomyopathy
atrial fibrillation that may cause heart failure
Why would a pregnant patient see an improvement in Grave’s disease during the course of her pregnancy?
pregnancy suppresses the immune system
What 3 antibodies will likely be present in Grave’s disease?
65% chance of (+) TSI
75% chance of (+) anti-TPO
55% chance of (+) anti-Tg
In thyroiditis, you would want to order _____. What will the result be?
Often have increased ESR
Typically have negative antithyroid antibodies
If you suspect Thyrotoxicosis Factitia, what do you want to order? why?
serum thyroglobulin (Tg) levels, should be low because thyroid meds do NOT have Tg
Why would you order Radioactive Iodine (RAI) Uptake/Scanning? What does an elevated uptake mean? decreased uptake?
to help determine thyrotoxicosis etiology
Elevated Uptake - Graves Disease, toxic solitary nodule, toxic multinodular goiter, type I amiodarone thyrotoxicosis
Decreased Uptake - thyroiditis, iodine-induced thyrotoxicosis, type II amiodarone thyrotoxicosis
What is a drawback to Radioactive Iodine (RAI) Uptake/Scanning?
Does not differentiate between cancer and other etiologies
_____ may help evaluate thyromegaly, nodules. What are two drawbacks?
_____ can identify increased blood flow Limitations of thyroid US
Thyroid Ultrasound
1. Does not delineate between benign and cancerous lesions
2. Does not delineate metabolic activity of tissue
Color flow Doppler sonography
this complication of thyrotoxicosis can cause extraocular muscle entrapment, diplopia, optic nerve compression, and corneal drying with incomplete lid closure. What am I? What is the treatment?
Severe ophthalmopathy
Treated with steroid therapy or, if severe, radiation or surgery
seen in graves disease and ocular myasthenia gravis
**What are the complications of thyrotoxicosis on the heart and lungs?
Cardiac - **Arrhythmias (including atrial fibrillation) and heart failure
Pulmonary - Dyspnea, pulmonary hypertension
What are two additional complications of thyrotoxicosis?
Calcium - Hypercalcemia, osteoporosis, nephrocalcinosis
**Hypokalemic periodic paralysis - symmetric flaccid paralysis after IV dextrose, oral carbs, or vigorous exercise - in Asian or American Indian men
**_____ symmetric flaccid paralysis after IV dextrose, oral carbs, or vigorous exercise. Common complication of _____. What is the MC pt population?
Hypokalemic periodic paralysis
Thyrotoxicosis
asian or american indian men
______ is a severe, life-threatening thyrotoxicosis. May be triggered by illness, RAI administration, thyroid surgery.
thyroid storm
Marked delirium
Severe tachycardia
Vomiting and diarrhea
Dehydration
Very high fever
What am I?
What is the tx?
What do you need to avoid?
thyroid storm
Treatment in order:
Beta blocker
Thionamide drug
Iodine (give at least 1 hour after thionamide drug)
hydrocortisone
Avoidance of aspirin and NSAID therapy: because it will knock off T3/4
What is the definitive treatment for thyroid storm?
once the pt is stable, radioactive iodine or surgery
What is the definition for Subclinical Hyperthyroidism? what are they at risk for?
Normal serum FT4 and T3 with low TSH
osteopenia/osteoporosis and caradiac arrhythmias
What is the tx for Grave’s disease?
Beta Blockers: propranolol and atenolol
++iodinated contrast agents: iopanoic acid, ipodate sodium <- not available in the US
Thionamide (Thiourea) Drugs
____ inhibit production of thyroid hormone. SE include agranulocytosis, aplastic anemia, and hepatotoxicity. What are the two medications?
Thionamide (Thiourea) Drugs
Methimazole
Propylthiouracil (PTU)
_____ is the medication for hyper that is commonly used in most patients except if they are pregnant. Then use ______
Methimazole
Propylthiouracil (PTU)
_______ inhibits organification of iodine, blocking formation of thyroid hormone. What is the dosing schedule?
Methimazole
start dosing higher and slowly decrease
______ carries greater risk of teratogenicity but has LESS risk of hepatotoxicity
Methimazole
_____ inhibits organification of iodine, blocking formation of thyroid hormone; also decreases peripheral tissue conversion of T4 to T3. What is the titration schedule?
Propylthiouracil (PTU)
may start higher in moderate and severe cases
**_____ carries a BBW for a greater risk of hepatotoxicity and is safe to give to preg pts
Propylthiouracil (PTU
What is the definitive tx for Grave’s disease?
Destruction of overactive thyroid tissue via
Radioactive Iodine (131I, RAI)
Surgery
For radioactive iodine, you need to d/c _____ for at least 4 days prior and may worsen _______, so need to give ______ concurrently
Methimazole
ophthalmopathy
steroids
NOT SAFE IN PREG
Surgery for Graves disease, need to give ______ pre-op to make sure their thyroid is normal, What are some complications?
thionamide drugs
damage to recurrent laryngeal nerve, hypoparathyroidism
What is the tx for Toxic Solitary Nodule?
Symptomatic - BB + methimazole or PTU
Keep TSH slightly suppressed to inhibit further growth of nodule
Surgery - if pt is <40 y/o or in healthy older patients
RAI may be given to patients who are not surgical candidates
What is the tx for Amiodarone-Induced thyrotoxicosis?
BB + methimazole
D/C amiodarone but it takes several months to clear out of the thyroid
refractory cases: surgery
What is the tx for Toxic Multinodular Goiter?
Symptomatic - BB + methimazole or PTU
Surgery - definitive treatment; total or near-total thyroidectomy
RAI may be given to patients who are not surgical candidates
**What is the tx for Thyroiditis? What should you NOT give?
Symptomatic - BB therapy; iodinated contrast agents if severe
NSAIDs or opioids as adjunct for pain management
**Thionamides - ineffective; thyroid hormone production is low
______ is the MC thyroid disorder in the US. What antibodies are associated with it?
Hashimoto (Autoimmune) Thyroiditis
Associated with (+) anti-TPO and (+) anti-Tg
What are some risk factors for Hashimoto (Autoimmune) Thyroiditis?
head-neck radiation, + family hx, hepatitis C, iodine deficiency
6x more common in women
What are the characteristics of painless postpartum thyroiditis and painless sporadic thyroiditis? Both are called _____
Transient hyperthyroidism followed by transient hypothyroidism
silent thyroiditis
______ is believed to be due to a viral infection (often URI) MC in young and middle aged women in the summer
Subacute thyroiditis
ask about hx of cold s/s
_______ nonviral thyroid gland infections that is primarily seen in immunosuppressed patients. severe pain, tenderness, redness and fever.
Suppurative (infectious) thyroiditis
_____ rarest thyroiditis; often due to systemic fibrosis. woody or ligneous thyroiditis. MC in middle aged or elderly women. asymmetric, stony, adherent thyroid gland. May have associated dysphagia, dyspnea, pain, hoarseness
Riedel (IgG4) thyroiditis
______ diffusely enlarged, firm, finely nodular thyroid
Usually no pain or tenderness associated; may have “tight” feeling in neck
Often complain of hypothyroid symptoms
May be more prone to depression and fatigue even once thyroid labs WNL
Hashimoto thyroiditis
_____ acute enlargement of thyroid gland. Often associated with pain and dysphagia
Subacute thyroiditis
thyroid will be sore
Often have hx of recent URI
Many pts have thyrotoxicosis for ~4 wks, then hypothyroidism x 4-6 months
____ and ____ antibodies are used to dx Hashimoto thyroiditis. What other disease can they also be consistent with?
anti-TPO and/or anti-Tg antibodies
celiac disease
Subacute thyroiditis is ____ in nature and have elevated _____ rate
viral in nature
elevated ESR levels but low antithyroid antibody titers
Suppurative thyroiditis is ____ in nature. and have elevated ____ and _____.
bacterial in nature
elevated ESR and leukocytes
What can you see in the labs values for Riedel thyroiditis?
May have normal thyroid labs, or signs of hyper- or hypothyroidism
Anti-TPO is seen in what 2 thyroid diseases? what percent of each? What does a high value indicate?
Hashimoto Thyroiditis (~95% of pts)
Can also be seen with Graves Disease (~70%)
Hashimoto thyroiditis or Graves disease
Anti-Tg is seen in what 2 thyroid diseases? what percent of each? What does a high value indicate?
Hashimoto Thyroiditis (~70% of pts)
Graves Disease (~55%
Hashimoto thyroiditis, Graves disease
Hashimoto thyroiditis will look ____ on US. Suppurative you are a looking for ____ on US.
Hyper due to Graves Disease will have _____ vascularity. Hyper due to thyroiditis will have ____ vascularity
Hashimoto thyroiditis - diffuse heterogeneous texture
Suppurative - Can identify presence of abscess
Hyper Graves: increased vascularity
Thyroiditis: normal or decreased vascularity
How do you distinguish Graves from thyroiditis? What will the results show?
RAI Uptake Scanning
Graves Disease - increased RAI uptake
Thyroiditis - typically has low RAI uptake
Fine needle biospy of Hashimoto thyroiditis carries an ____% chance of cancer. What is the next step in suppurative FNA?
8% chance of cancer
Suppurative - FNA biopsy with Gram stain and culture required
Hashimoto thyroiditis has a higher risk ?????. Regular thyroiditis has a high risk of _____
of 1st trimester pregnancy loss (if untreated)
depression
What is the treatment for Hashimoto thyroiditis?
may observe if asymptomatic and minimally enlarged or normal size thyroid gland
Hypothyroidism - replacement with levothyroxine
Large gland/goiter - may try levothyroxine suppressive therapy
What is the tx for Subacute thyroiditis? What if it is severe?
high-dose aspirin or NSAIDs are tx of choice
+/- corticosteroids for severe or refractory cases
BB can be helpful for acute symptoms
iodinated contrast agents
What is the treatment for suppurative thyroiditis? Riedel thyroiditis
antibiotics, surgical drainage of abscess
tamoxifen +/- steroid therapy
______ state of abnormal thyroid function studies in the setting of severe nonthyroidal illness. What is the underlying cause? What is the pathophysiology? What is the treatment?
Sick Euthyroid Syndrome
**Thought to be due to cytokines, especially IL-6
impaired deiodination of T4 to T3
DO NOT CHANGE thyroid meds, treat the underlying cause
palpable thyroid nodules are present in ____ of adult women and ____ of adult men in US. **____ of palpable (≥ 1 cm) nodules are benign. Describe the patients thyroid function.
5-6%
1.5%
87%
normal
Cancer is estimated ___ of palpable thyroid nodules . What are some risk factors? What are some characteristics?
10%
Risk: radiation especially to head/neck, family hx
characteristics:
Large nodule(s)
Adherence to local structures
Hoarseness or vocal cord paralysis
Lymphadenopathy
What are some s/s of large multinodular goiters?
swelling, hoarseness, dysphagia
Retrosternal - dyspnea, facial erythema, jugular vein distension
What are the dx test need to correctly dx a Thyroid Nodules/Goiter? give reasoning as to why you are ordering that test
TSH (FT4, autoimmune labs): high or low
Thyroid US: will evaluate size, characteristics, single/multi
RAI Uptake: evaluation of hyperfunctioning thyroid tissue
(NOT FIRST LINE) CT scan: Helpful to delineate very large nodules or MNG, degree of extension into mediastinum, and presence of tracheal compression
FNA Biopsy: most commonly used to evaluate thyroid nodules for malignancy
**What are concerning features to see on a Thyroid US? What type is usually benign?
size/shape - irregular margins, large (>1 cm)
consistency - solid, heterogeneous texture
abnormal vascularity
microcalcifications
benign: cystic lesions
On a RAI uptake scan you see a “cold” nodule. What does this mean? “hot” nodule?
“cold” nodules with little uptake
higher cancer risk
“hot” nodules with high uptake
lower cancer risk
Will a cold nodule appear white or black on a RAI scan? What about hot?
Cold: shows up white
hot: shows up black
When is a FNA biopsy indicated? If there are multiple, how many do you bx?
1+ cm and suspicious appearance (irregular margins, microcalcifications)
2 cm or larger
Associated cervical lymphadenopathy
Nodule is growing
biopsy of four largest nodules (1 cm +) and any specific nodules of concern (see above)
What is the management for a non-cancerous non-toxic thyroid nodule/goiter? What risks are increased due to nodule?
regular palpation and US imaging Q 6 months initially, then yearly after stable
Avoidance of excessive iodine intake
Medication aimed at the s/s -> LT4 Suppression - if nodule >2 cm and normal or high TSH OR thionamide drugs if s/s are hyper
Ethanol injection - shrinkage of benign nodules
increased risk of: heart disease, osteoporosis, hyperthyroidism
What is the management for a toxic thyroid nodule/goiter?
surgery
RAI therapy
What is the risk of RAI therapy? Shrinks nodules up to ____
hypothyroidism
60%
thyroid cancer is more common in _____. Younger or older?
women
older
_____ is the MC type of endocrine cancer.
thyroid cancer
**_____ is the MC type of thyroid cancer. What percentage? How does it usually present? Is it aggressive or passive? Is it metabolically active?
Papillary Thyroid Carcinoma
80%
Usually presents as a single thyroid nodule
**Least aggressive form of thyroid cancer, best survival rates
NOT very metabolically active, will have some RAI uptake
______ is the 2nd MC thyroid cancer. What percent? Is it likely to metastasize? Is it metabolically active?
Follicular Thyroid Carcinoma 14%
Likely to metastasize to distant sites
High level of iodine uptake - RAI scanning and treatment
_____ is the 3rd MC type of thyroid cancer. What percentage? Is it likely to metastasize? Is it metabolically active? What is unique about this thyroid cancer?
Medullary Thyroid Carcinoma 3%
local metastases
Does NOT have good iodine uptake
***secretes all the hormones that are not thyroid aka calcitonin, prostaglandins, 5HT, ACTH, CRH
_____ is the most aggressive form of thyroid carcinoma with the worst survival rate. What is the classic presentation? Is it metabolically active?
Anaplastic Thyroid Carcinoma
rapidly enlarging mass in multi-nodular goiter (MNG) aka one nodule grows super fast in a group of multiple
Does NOT have good iodine uptake
palpable, firm, nontender thyroid nodule or mass
often asymptomatic
May see neck discomfort, dysphagia, hoarseness
Occasionally will have symptoms of hyper- or hypothyroidism
lymph node involvement
What am I?
Where are the MC sites?
thyroid cancer
local lymph nodes, lungs, bone
Lymph node involvement in ~15% of adults and ~60% of children
_______ thyroid cancer may present with flushing and diarrhea (30%) and can rarely have s/s of Cushing dz. _____ is more likely to have s/s of metastasis, local invasion
Medullary
Anaplastic
**hyperthyroidism may be present in _____ thyroid cancer. Serum thyroglobulin levels are elevated in _____ and ____ cancer. What is the limitation?
follicular
metastatic papillary
follicular
invalid if anti-Tg present; may be falsely ↑ in thyroiditis
____ and ____ are elevated in medullary thyroid cancer
Serum calcitonin: high in thyroiditis, pregnancy, azotemia, hypercalcemia, other cancers
Serum CEA: also elevated in other cancers
When is Tg utlized?
Assist with evaluating extent of papillary and follicular thyroid cancers, their prognosis, and their response to treatment
Anti-Tg antibodies can cause false readings
When is calcitonin ordered?
to screen for medullary thyroid carcinoma - evaluate extent of cancer and response to tx
When is a CEA ordered? What other conditions is it also elevated in?
carcinoembryonic antigen
Assist with evaluating extent of certain cancers, and response to tx
Elevated in smokers and due to many noncancerous dx (e.g. IBD, cirrhosis)
What thyroid cancer is best dx with RAI scan? Why?
follicular because it is metabolically active and will pick up iodine
_____ is the treatment of choice for thyroid cancers.
> 1 cm, known to be cancer proceed with ______
< 1 cm, known to be cancer proceed with _____
< 4 cm indeterminate lesion proceed with _____
> 4 cm indeterminate lesion proceed with _____
surgery!!!
> 1 cm, known to be cancer - total thyroidectomy + cervical lymph node dissection
< 1 cm, known to be cancer - may consider lobectomy
well-differentiated, pt is young (< 45), no lymph node 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
What are some complications of thyroid sx?
Laryngeal nerve palsy or permanent injury, hypoparathyroidism, airway swelling, bleeding, infection
What is the tx for differentiated thyroid cancers aka follicle aka super slow growing?
Thyroxine Suppression, add DEXA screening
RAI Therapy: CI in women who are pregnant or nursing, or who lack childcare
What is the tx for anaplastic thyroid cancer?
local resection and radiation (old school radiation)
because they are unresponsive to RAI and most chemotherapies
When do most differentiated cancers recur? What is the monitoring?
recur within 5-10 years after tx
At least a yearly thyroid US
thyroglobulin: for follicular and papillary
TSH should be suppressed (goal is below 0.1)
RAI scan if cancer is well differentiated
