thyroid disorders pt 2 Flashcards
state of excessive levels of T3 and T4
Thyrotoxicosis
increased state of thyroid function
Hyperthyroidism
types of Hyperthyroidism
- 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
thyrotoxicosis is MC in who? who has a higher incidence?
5x more common in women
Higher incidence in smokers
MC cause of Thyrotoxicosis
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
MC onset of thyrotoxicosis
women ages 20-40
Assists with diagnosis of Grave’s Disease
May be a follow-up to other abnormal thyroid function studies
Thyroid-Stimulating Ig (TSI)
AKA TSH receptor antibodies, TSHrAb
Interfering Factors of Thyroid-Stimulating Ig (TSI)
Recent administration of radioactive iodine can interfere with results
Titers may not decline for up to 1 year after treatment
high Thyroid-Stimulating Ig (TSI) means what?
Graves disease
causes of Thyrotoxicosis
- 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
symptoms of thyrotoxicosis
- 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
signs of thyrotoxicosis
- 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
manifestations of graves disease
- Graves ophthalmopathy
- Thyroid acropachy
- Graves dermopathy
(pretibial myxedema)
pt has
Upper eyelid retraction
Lid lag with downward gaze
“Staring” appearance
May see conjunctival edema and inflammation
what do they have?
Graves ophthalmopathy
pt with
Digital clubbing
Swelling of fingers and toes
Periosteal reaction of extremity bones
what do they have?
Thyroid acropachy
pt has
Erythematous, rough plaques
Lymphoid infiltration and glycosaminoglycans accumulation in affected skin
what do they have?
Graves dermopathy
(pretibial myxedema)
Thyrotoxicosis - Clinical Presentation in Special Cases
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
basic diagnostic labs of thyrotoxicosis
- 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
if Grave’s disease what labs would you see
65% chance of (+) TSI
75% chance of (+) anti-TPO
55% chance of (+) anti-Tg
If Thyroiditis what would the labs look like?
Often have increased ESR
Typically have negative antithyroid antibodies
Low serum thyroglobulin (Tg) levels is indicative of?
Thyrotoxicosis Factitia
what is Radioactive Iodine (RAI) Uptake/Scanning
Measures thyroid metabolism by radioactive tracer iodine uptake
May help determine thyrotoxicosis etiology
elevated uptake of Radioactive Iodine (RAI) Uptake/Scanning means?
Graves Disease, toxic solitary nodule, toxic multinodular goiter, type I amiodarone thyrotoxicosis
decreased uptake of Radioactive Iodine (RAI) Uptake/Scanning means?
thyroiditis, iodine-induced thyrotoxicosis, type II amiodarone thyrotoxicosis
what does Radioactive Iodine (RAI) Uptake/Scanning NOT differentiate?
between cancer and other etiologies
Radioactive Iodine (RAI) Uptake/Scanning requires what, therefore avoid pregnant women
radiation
what imaging may help evaluate thyromegaly, nodules
Thyroid Ultrasound
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
complications with thyrotoxicosis
- Ophthalmic - Severe ophthalmopathy = extraocular muscle entrapment, diplopia, optic nerve compression, and corneal drying with incomplete lid closure
- Cardiac - Arrhythmias and HF
- Pulmonary - Dyspnea, pulmonary hypertension
- 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 - Thyroid Storm - Severe, life-threatening thyrotoxicosis
____ is also associated with Graves disease (ophthalmic)
Ocular myasthenia gravis
tx for Ocular myasthenia gravis
steroid therapy
severe - radiation or surgery
tx for cardiac complications from thyrotoxicosis
(Arrhythmias and HF)
cardiac medications - BBs, digoxin, anticoagulation
what can trigger a thyroid storm
illness, RAI administration, thyroid surgery
manifestations of thyroid storm
thyrotoxicosis symptoms, but worse
Marked delirium
Severe tachycardia
Vomiting and diarrhea
Dehydration
Very high fever
tx for thyroid storm
- Thiourea drug - Methimazole or PTU
- Inhibit oxidation of iodine, prohibiting thyroid hormone formation - Iodinated contrast agent - ipodate sodium or iopanoic acid
- Inhibit peripheral conversion of T4 to T3 - Beta blocker - propranolol or atenolol
- Relieves symptoms (tachycardia, tremor, anxiety) - Hydrocortisone
- Avoidance of aspirin therapy - Definitive tx - radioactive iodine or surgery
Normal serum FT4 and T3 with low TSH
what type of Thyrotoxicosis
Subclinical Hyperthyroidism
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
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
prognosis of subclinical hyperthyroidism
- 1-2% per year progress to symptomatic thyrotoxicosis
- If multinodular goiter - 5% per year progress
tx for Grave’s disease
- Beta Blockers - propranolol, atenolol
- Iodinated Contrast Agents - iopanoic acid, ipodate sodium
- Thiourea Drugs - methimazole, Propylthiouracil (PTU)
what medication
Improves tachycardia, palpitations, anxiety, tremor, etc.
Often given initially for s/s until antithyroid therapies have a chance to work
BBs
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
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
which Thiourea Drug is preferred in most pts
Methimazole
which thiourea drug is preferred if first trimester or breastfeeding
Propylthiouracil (PTU)
MOA of Methimazole
inhibits organification of iodine, blocking formation of thyroid hormone
indications of Methimazole
General hyperthyroidism, hyperthyroidism due to Graves Disease
SE of Methimazole
- greater risk of teratogenicity and goes more into breast milk than PTU
- Derm - pruritus, rash, urticaria
- MSK - joint pain
- GI - abnormal taste, N/V, hepatotoxicity (less risk of hepatotoxicity than PTU)
- Heme - agranulocytosis (greatest risk in first 2-3 months of tx)
how to monitor methimazole
thyroid labs; CBC; liver function tests
MOA of Propylthiouracil (PTU)
inhibits organification of iodine, blocking formation of thyroid hormone; also decreases peripheral tissue conversion of T4 to T3
indications of Propylthiouracil (PTU)
Hyperthyroidism
SE of Propylthiouracil (PTU)
- Carries greater risk of hepatotoxicity than methimazole - has a black box warning
- Derm - pruritus, rash, urticaria
- MSK - joint pain
- GI - abnormal taste, N/V, hepatotoxicity (higher risk than methimazole)
- Heme - agranulocytosis (greatest risk in first 2-3 months of tx)
- Reproductive - lower risk of teratogenicity and breast milk transmission
CI of PTU
hypersensitivity to rx; in Canada, breastfeeding is also a CI
how to monitor while on PTU
thyroid labs; CBC; liver function tests
definitive tx of grave’s disease
destruction of overactive thyroid tissue
1. Radioactive Iodine (131I, RAI)
2. Surgery
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)
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
what drug can cause reduced efficacy of Radioactive Iodine (131I, RAI)
Methimazole
d/c at least 4 days prior
which tx of grave’s disease may worsen ophthalmopathy? what should be given to tx that?
Radioactive Iodine (131I, RAI)
steroids
which drug is used to ensure patients are euthyroid at surgery
Thiourea drugs pre-op
complications with surgery for grave’s disease tx
damage to recurrent laryngeal nerve, hypoparathyroidism
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
tx for Amiodarone-Induced
-
Sx - BB + methimazole
- Adjunct therapy of iodinated contrast agent if needed - D/C amiodarone does not have a significant impact for several months
- Refractory cases - surgery
tx for Toxic Multinodular Goiter
-
Sx - BB + methimazole or PTU
- 95% recurrence if thiourea drug is discontinued -
Surgery - definitive tx; thyroidectomy
- Relieves feeling of pressure and visible external swelling
- Allows for evaluation and removal of potential occult cancers - RAI - for pts who are not surgical candidates
tx for Thyroiditis
- Thioureas - ineffective; thyroid hormone production is low
- Symptomatic - BB therapy; iodinated contrast agents if severe
- NSAIDs or opioids as adjunct for pain management
MC thyroid disorder in the US
Hashimoto (Autoimmune) Thyroiditis
- 6x MC in women
- Risks - head-neck radiation, + family hx, hepatitis C, iodine deficiency
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
what are the “silent” thyroiditis
-
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 -
Painless sporadic thyroiditis - subacute Hashimoto thyroiditis
- Similar to painless postpartum thyroiditis, but not associated with pregnancy
cause of subacute thyroiditis
- believed to be due to a viral infection (often URI)
- AKA - de Quervain thyroiditis, granulomatous thyroiditis, giant cell thyroiditis
- Up to 5% of clinical thyroid disease
- MC - young and middle-aged women, summer
cause of suppurative (infectious) thyroiditis
- nonviral thyroid gland infection
- More common in immunosuppressed > non-immunosuppressed
cause of Riedel thyroiditis
- rarest thyroiditis; often due to systemic fibrosis
- AKA - Riedel struma, woody or ligneous thyroiditis, invasive fibrous thyroiditis
- MC - middle-aged or elderly women
clinical presentation of hashimoto’s
- 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
clinical presentation of painless postpartum thyroiditis
- may have some thyroid enlargement
- Transient hyperthyroidism beginning 1-6 months after delivery
- Hyperthyroidism lasts x 1-2 months
- Hypothyroidism tends to follow and lasts for a few months
clinical presentation of painless sporadic thyroiditis
- 50% may have a small, nontender goiter
- Transient hyperthyroidism x 1-2 months
- Transient hypothyroidism for a few months
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
clinical presentation of suppurative thyroiditis
- severe pain, tenderness, redness, and fluctuance associated with the thyroid gland
- Often have associated fever
- Typically have hx of immunosuppression
clinical presentation of Riedel thyroiditis
- asymmetric, stony, adherent thyroid gland
- May have associated dysphagia, dyspnea, pain, hoarseness
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
labs for Subacute thyroiditis
- elevated ESR levels
- low antithyroid antibody titers
- May have thyroid labs consistent with hyper- or hypothyroidism
labs for Suppurative thyroiditis
- Elevated ESR and leukocytes
- Often normal thyroid function studies and antithyroid antibodies
labs for Riedel thyroiditis
May have normal thyroid labs, or signs of hyper- or hypothyroidism
Use of Anti-TPO labs
- Assist with diagnosis of autoimmune thyroid disease
- esp Hashimoto Thyroiditis (~95% of pts)
- can be with Graves Disease (~70%) and other conditions
interpretation of high anti-TPO
- Autoimmune thyroid disease - Hashimoto, Graves
- Other thyroid conditions - cancer, goiter
- Other AI conditions - RA, pernicious anemia, rheumatoid-collagen disease
interpretation of high anti-Tg
- Autoimmune thyroid disease - Hashimoto thyroiditis, Graves disease
- Other thyroid conditions - cancer, goiter
- Other AI conditions - RA, pernicious anemia, rheumatoid-collagen disease
how would thyroid ultrasounds look like/be helpful?
- Hashimoto thyroiditis - diffuse heterogeneous texture
- Suppurative - Can identify presence of abscess
- Hyperthyroidism - can help distinguish cause
- Graves Disease - increased vascularity
- Thyroiditis - normal or decreased vascularity
how would RAI uptake scanning be helpful/look like?
- Hyperthyroidism - can help distinguish Graves from thyroiditis
- Graves Disease - increased RAI uptake
- Thyroiditis - typically has low RAI uptake
FNA biopsy can be helpful in what thyroiditis conditions
- Hashimoto thyroiditis - Nodules carry an 8% chance of cancer
- Suppurative - FNA biopsy with Gram stain and culture required
complications with thyroiditis
- Abnormal thyroid function
- Thyrotoxicosis and thyroid storm
- Hypothyroidism - temporary or permanent - Higher risk of depression
- Pressure on local neck structures
- Hashimoto - Higher risk of 1st trimester spontaneous miscarriage (if untreated)
- Suppurative - Abscess and/or chronic sinus tract formation
- Cancer - Associated with chronic thyroiditis
management for thyroiditis (all conditions)
- Hashimoto - observe (asx and minimally enlarged or normal size thyroid gland)
- Hypothyroidism - replacement with levothyroxine
- Large gland/goiter - may try levothyroxine suppressive therapy - 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 - Suppurative thyroiditis - antibiotics, surgical drainage of abscess
- Riedel thyroiditis - tamoxifen and/or steroid therapy
- Surgery for decompression if needed
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
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
what would labs look like for sick euthyroid syndrome?
varies in TSH, T3, T4, rT3, and FT4
depends on severity and underlying cause
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
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
prevalence of Thyroid Nodules/Goiter
- Most nodules (≥ 1 cm) are benign (87%)
- MC - iodine-deficient areas, increased age
- Non-palpable nodules - 30% of pts on US; 60% on autopsy
- Multinodular Goiter - about 50% of palpable nodules are actually MNG
thyroid function of thyroid nodules/goiter are ?
euthyroid
Higher rates of hypothyroidism or hyperthyroidism than avg pt
what % of palpable thyroid nodules is cancer? what increases the risk?
- 10%
- Radiation - increased risk with hx of head/neck or total body radiation
- Family Hx - increased risk with (+) family hx of thyroid cancer
-
Characteristics - increased risk with:
- Large nodule(s)
- Adherence to local structures
- Hoarseness or vocal cord paralysis
- Lymphadenopathy
s/s of small, solitary nodules
typically asx
May be incidentally found on exam/imaging
s/s of large multinodular goiters
- may see swelling, hoarseness, dysphagia
- Retrosternal - dyspnea, facial erythema, jugular vein distension
s/s of abnormal thyroid function
- 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
what diagnostic testing are you getting for thyroid nodules/goiter?
- TSH - for all pts found to have a nodule/ goiter
- +/- FT4, autoimmune labs - Imaging
- Thyroid US
- RAI uptake
- CT Scan - Fine-Needle Aspiration Biopsy (FNA Biopsy)
during thyroid US for a nodule/goiter, what features make it more concerning?
- Concerning Features
- irregular margins
- solid lesions
- heterogeneous texture
- abnormal vascularity
- microcalcifications
- larger nodules (>1 cm)
what diagnostic testing evaluates size and characteristics of nodule, and if nodule is part of MNG or solitary
thyroid US
what diagnostic testing evaluates hyperfunctioning thyroid tissue
RAI Uptake
what diagnostic testing is helpful to delineate very large nodules or MNG, degree of extension into mediastinum, and presence of tracheal compression
CT scan
a RAI uptake of an nodule is “cold”
what does this mean?
hypofunctioning/lower iodine intake
higher cancer risk
a RAI uptake of a nodule is “hot”
what does this mean?
hyperfunctioning/high iodine intake
lower cancer risk
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
biopsy of thyroid nodule is indicated if:
- +1 cm and suspicious appearance (irregular margins, microcalcifications)
- +2 cm
- Associated cervical LAN
- Nodule is growing
what makes a nodule a low index of suspicion
- Hx
- Family history of goiter
- Residence in area of endemic goiter - physical characteristics
- Older patient
- Female
- Soft nodule
- Smaller size (<1 cm)
- Multinodular goiter - Serum factors
- High titer of thyroid antibodies, especially anti-TPO - FNA biopsy
- Colloid nodule or adenoma - Imaging
- Hot nodule on RAI
- Cystic lesion on US
- Shell-like calcification - Response to LT4 therapy
- Regression after 6 months of tx
what makes a nodule have high index of suspicion
- hx
- Previous radiation of head/neck/chest
- Hoarseness - physical characteristics
- Younger patients or pediatric
- Male
- Firm or hard nodule
- Large nodule (>2 cm)
- Solitary nodule
- Vocal cord paralysis
- Enlarged LN - serum factors
- Elevated calcitonin or CEA - serum factors
- Papillary carcinoma
- Follicular lesion
- Medullary or anaplastic carcinoma - FNA biopsy
- Cold nodule on RAI
- Solid lesion on US
- Punctate calcification - response to LT4 therapy
- Increase in size
management for thyroid nodule/goiter
-
General f/u - regular palpation and US imaging
- Q 6 months initially, then yearly
- Avoidance of excessive iodine intake -
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 - Thiourea drugs +/- BB - if s/s of thyrotoxicosis
- Surgery - cancer, hyperfunctioning nodules, toxic MNG
- Ethanol injection - shrinkage of benign nodules
-
RAI therapy - toxic thyroid adenomas, toxic MNG, Graves
- Shrinks nodules by up to 60%
- Risks - hypothyroidism
thyroid cancer is MC in who?
- women (3:1)
- Increasing incidence with age
- MC endocrine cancer
- Most remain microscopic and indolent
1st and 2nd MC thyroid cancer?
Papillary Thyroid Carcinoma
Follicular Thyroid Carcinoma
characteristics of papillary thyroid carcinoma
- Usually presents as a single thyroid nodule
- 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 - can be autosomal dominant trait
- not much radioactive iodine uptake
which thyroid cancer is most likely to metastasize to distant sites
High level of iodine uptake - RAI scanning and treatment
Follicular Thyroid Carcinoma
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
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
presentation of thyroid cancer
- PE - palpable, firm, nontender thyroid nodule or mass
- Symptoms - often asx
- neck discomfort, dysphagia, hoarseness
- sometimes symptoms of hyper- or hypothyroidism - 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 - Anaplastic - more likely to have s/s of metastasis, local invasion
- Medullary - flushing and diarrhea (30%)
- Cushing-like symptoms (Rare)
diagnostic labs for thyroid cancer
- Hyperthyroidism - can be in follicular thyroid carcinoma
- Serum thyroglobulin - elevated in metastatic papillary and follicular CA
- Limitations - invalid if anti-Tg present; may be falsely ↑ in thyroiditis - 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 - 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
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
interfering factors of Tg
- Elevated in benign conditions (thyroiditis, post-thyroid exam)
- Thyroid HRT - suppress residual or metastatic thyroid tissue = falsely low Tg levels
- Anti-Tg antibodies - false readings
interpretation of high Tg
- Cancer - papillary or follicular thyroid cancer
- Others - thyroiditis, thyroid trauma or recent examination
uses for calcitonin labs
- 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
interfering factors of calcitonin labs
- Elevated
- pregnancy and neonates
- meds - calcium, oral contraceptives
interpretation of high calcitonin
- Medullary thyroid carcinoma
- Non-cancer thyroid disorders - parafollicular cell hyperplasia, thyroiditis
- Other cancers - breast, pancreatic, lung
- Others - hyperparathyroidism, cirrhosis, pernicious anemia
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
interfering factors of CEA
- Elevated in smokers and due to many noncancerous dx (e.g. IBD, cirrhosis)
- Not all cancers in target tissues produce CEA
interpretation of high CEA
- Cancer - GI, breast, lung, pancreatic, hepatobiliary, medullary thyroid
- Others - inflammation, cirrhosis, peptic ulcer
diagnostic imaging for thyroid cancer
- Thyroid US - Helpful for determining size and location of mass
- More sensitive > CT/MRI for evaluating neck metastases - RAI Scan - Can use after thyroidectomy to do whole-body scans
- May reveal presence of metastatic tissue
- Not all thyroid cancers concentrate iodine well! - CT/MRI - Can help evaluate distant metastases (lung, liver, bone) or help delineate retrosternal masses
- PET Scanning - Helpful for detecting mets not visible on RAI scanning
- Lacks specificity for thyroid cancer; expensive
what is the papillary or follicular Ca staging
undifferentiated or anaplastic carcinomas are ALL stage IV
management for thyroid cancer
-
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 -
Thyroxine Suppression - For differentiated thyroid cancers
- Must monitor thyroid labs; consider periodic bone density screening -
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 - Chemotherapy - for aggressive differentiated cancers
- Anaplastic Thyroid Carcinoma - local resection and radiation
- Unresponsive to RAI and most chemotherapies
Complications of Surgery
Laryngeal nerve palsy or permanent injury, hypoparathyroidism, airway swelling, bleeding, infection
f/u for thyroid cancer
- Recurrence - Most differentiated cancers recur within 5-10 years after tx
- 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 - Prognosis - 10-yr survival rates
- >90% with papillary and follicular thyroid carcinomas
- ~78% with medullary thyroid carcinoma
- ~7% with anaplastic thyroid carcinoma
