Lecture 18: Thyroid Disorders Part 2 Flashcards
What is thyrotoxicosis?
State of excessive T3/T4.
What is hyperthyroidism?
A state of increased thyroid function.
What is the most common demographic for hyperthyroidism?
Women > 60, esp if they smoke.
Same as hypothyroidism as well.
What is the MCC for thyrotoxicosis?
Graves disease (60-80%)
What is Graves Disease?
Autoimmune disorder in which autoantibodies bind to TSH receptors, causing excessive thyroid function.
What tests can be positive for Graves Disease?
- Thyroid stimulating Ig (TSI, 65% +)
- Anti-TPO (75% +)
- Anti-Tg (55%)
When is the most common onset of Graves Disease?
Women ages 20-40
What are TSI tests used for?
Assisting in the diagnosis of Graves Disease.
What is the first line test to check for Graves?
TSH/FT4/Thyroid panel
What can interfere with TSI lab tests?
Radioactive iodine
What are the common etiologies for excessive iodine in thyrotoxicosis?
- Iodinated radiocontrast dye
- High-iodine foods (kelp, nori)
- Potassium iodine, amiodarone, povidone iodine
What types of thyroiditis can cause thyrotoxicosis?
- Infectious/subacute
- Silent/postpartum
What are the general symptoms for thyrotoxicosis?
- Fatigue and weakness
- Weight loss with increased appetite
- Nervousness/restlessness
- Hyperactivity/irritability
- Palpitations/angina
- Muscle cramps
- Polyuria
- Diarrhea
- Heat intolerance and sweating
- Oligomenorrhea
What are the signs of thyrotoxicosis?
- Thin body habitus
- Agitation/restlessness
- Tachycardia
- AFib
- Muscle weakness, hyperreflexia, osteoporosis, fine resting tremors
- Goiter/thyromegaly
- Warm, moist skin
- Lid lag or lid retraction
What are the specific manifestations of Graves Disease?
- Graves Ophthalmology
- Thyroid acropachy
- Graves dermopathy
What does Graves Ophthalmology look like?
- Upper eyelid retraction
- Lid lag with downward gaze
- “Staring” appearance
- Conjunctival edema
What does thyroid acropachy look like?
- Digital clubbing
- Swelling of fingers and toes
- Periosteal reaction of extremity bones
What does Graves dermopathy/pretibial myxedema look like?
- Erythematous, rough plaques
- Lymphoid infiltration
What kind of cardiopulmonary manifestations can occur in Graves Disease?
- Forceful heartbeats
- Exertional dyspnea
- Abnormal conduction
- Cardiomyopathy
In what trimester of pregnancy is Graves Disease most common?
2nd trimester
Clinical
Why does Graves Disease see an improvement throughout pregnancy?
Physiologic suppression of the immune system.
Clinical
Divya is a 37-year-old female who was just diagnosed with primary hyperthyroidism. Assume she has not received any clinical interventions to treat her hormone status.
● What would we expect to happen to her T4 level?
● What would we expect to happen to her T3 level?
● What would we expect to happen to her TSH level?
● What would we expect to happen to her TRH level?
- T4 = elevated
- T3 = elevated
- TSH = decreased
- TRH = decreased
What lab abnormalities might we see in a primary hyperthyroidism patient?
- Hypercalcemia
- Elevated Alk phosphatase
- Anemic
- Decreased granulocytes
What lab is typically higher in thyroiditis over Graves Disease?
ESR
Low levels of what might suggest Thyrotoxicosis factitia?
Low serum thyroglobulin levels.
What imaging test might help us differentiate thyrotoxicosis etiologies?
Radioactive iodine uptake (RAI).
If I see increased uptake of iodine in an RAI test, what are the more likely etiologies?
- Graves Disease
- Toxic solitary nodule
- Toxic multinodular goiter
- Type 1 amiodarone thyrotoxicosis
If I see decreased uptake of iodine in an RAI test, what are the more likely etiologies?
- Thyroiditis
- Iodine-induced thyrotoxicosis
- Type 2 amiodarone thyrotoxicosis
What kind of person should almost never get an RAI test?
Pregnant women, since it contains radiation.
What are the limitations of a thyroid US?
- Cannot tell benign from malignant
- Cannot measure metabolic activity
- Depends on operator and body habitus
If a Graves patient has severe ophthalmologic manifestations, what is the typical treatment?
- Steroid therapy
- Severe: radiation or surgery
What is hypokalemic periodic paralysis and who is it MC in?
- Symmetric flaccid paralysis after IV dextrose, oral carbs of vigorous exercise.
- Asian or american indian men.
What is a thyroid storm? Manifestations?
Severe, life-threatening thyrotoxicosis
* Marked delirium
* Severe tachycardia
* Vomiting and diarrhea
* Dehydration
* Very high fever
What is the treatment protocol for a thyroid storm?
- Thiourea drug: methimazole or PTU (inhibits iodine oxidation, preventing formation of thyroid hormone.)
- Iodinated contrast agent: ipodate sodium or iopanoic acid (Inhibits peripheral conversion of T4 to T3)
- BB: propranolol or atenolol (symptomatic relief)
- Hydrocortisone
- AVOID ASA
What is the definitive treatment for a thyroid storm?
- Radioactive iodine
- Surgery
What lab values correspond to subclinical hyperthyroidism?
- Normal serum FT4 and T3
- Low TSH
Clinical
Excess ingestion of which food product can cause hyperthyroidism?
● Red meat
● Chamomile tea
● Kelp supplements
● Omega-3 fatty acids
KELP
Clinical
While useful to evaluate thyroid disease, thyroid ultrasonography is limited in that it cannot…
● Assess metabolic activity of a thyroid mass
● Distinguish a solid mass from a cystic mass
● Assess blood flow to the thyroid gland
● Evaluate smooth versus poorly defined mass margins
Assessing metabolic activity of a thyroid mass.
Clinical
Untreated hyperthyroidism could eventually lead to all of the following complications, except…
● Osteoporosis
● Peripheral edema
● Edema
● Evaluate smooth versus poorly defined mass margins
- Peripheral edema
- Edema
What medications do we give for Graves Disease patients?
- BBs (symptomatic relief until other therapy kicks in.)
- Iodinated contrast agents (severely symptomatic patients, but efficacy wanes over time)
- Thiourea drugs (Inhibits thyroid hormone production without damaging thyroid.)
What are the two thiourea drugs? When is one preferred over the other?
- Methimazole: Most patients
- Propylthiouracil (PTU): first trimester or breast feeding)
Pregnant titties being used = PTU preferred
What is the main SE of methimazole that makes it dangerous to use in pregnancy?
Teratogenicity risk and goes into breast milk.
What are the 2 MOAs of PTU?
- Inhibits organification of iodine, preventing formation of thyroid hormone.
- Decreases peripheral conversion of T4 to T3.
What is the BBW of PTU?
Hepatotoxicity
Clinical
Which of the following tests would be helpful when choosing whether to put a patient on methimazole or PTU?
● A urine hCG (pregnancy) test
● A comprehensive metabolic panel (CMP)
● A complete blood count (CBC)
● All of the above
All of the above
When do we use radioactive iodine for Graves Disease? When do we use surgery instead?
- RAI is not safe for pregnancy for lactation.
- Surgery is for those who are pregnant, refuse radiation, or are suspicious for malignancy.
Why is RAI more ideal for Graves Disease treatment?
No risk of damaging the recurrent laryngeal nerve or causing hypoparathyroidism.
What are the treatment options for a toxic solitary nodule causing thyrotoxicosis?
- Symptomatic: BB + PTU or methimazole
- Surgery: pt < 40 or healthy older pt.
- RAI: if not surgical candidate
What are the treatment options for amiodarone-induced thyrotoxicosis?
- Symptomatic: BB + methimazole
- D/C Amiodarone
- Surgery for refractory cases
What are the treatment options for a toxic multinodular goiter?
- Symptomatic: BB + Thiourea drug
- Surgery or RAI
What are the treatment options for thyroiditis?
- Thioureas: ineffective
- Symptomatic: BB or iodinated contrast agents
Clinical
Which of the following patients would be most likely to receive an iodinated contrast agent as treatment?
● A patient who is pregnant or breastfeeding
● A patient who is relatively young (< 40 y/o) and healthy
● A patient who presents to the ER with thyroid storm
● A patient with moderate s/s who is not a good surgical candidate
Thyroid storm patient
Only for severe symptoms.
Clinical
A patient with a toxic multinodular goiter has been symptom-free for 15 years with the use of with atenolol and methimazole. She decides to stop her medication, as she thinks it is likely that she no longer actually needs it. What would we expect to happen?
● The patient is likely to have a recurrence of her thyrotoxicosis
● The patient may have a recurrence of thyrotoxicosis, but is
much less likely to have s/s if she follows a low-iodine diet
● The patient is unlikely to have a recurrence of her thyrotoxicosis
as she has been symptom free for over one decade
● The patient is unlikely to have a recurrence of her thyrotoxicosis,
but may experience signs and symptoms of hypothyroidism
The patient is likely to have a recurrence of her thyrotoxicosis
Methimazole stoppage is highly associated with recurrence of thyrotoxicosis.
Atenolol is for symptoms only.
What is the MC thyroid disorder in the US?
Hashimoto autoimmune thyroiditis
What are the risk factors for hashimoto’s?
- Head-neck radiation
- Family Hx
- Hep C
- Iodine deficiency
What are the two silent thyroiditis etiologies?
- Painless postpartum thyroiditis
- Painless, sporadic thyroiditis
How does postpartum thyroiditis present?
Transient hyperthyroidism followed by transient hypothyroidism.
70% chance of recurrence in subsequent pregnancies.
What thyroiditis is viral? MC demographic?
Subacute thyroiditis, often due to an URI
MC demographic: young and middle-aged women in the summer.
What is suppurative thyroiditis?
Infectious thyroiditis that is NON-viral.
Rare in normal patients.
What is the rarest thyroiditis? What causes it? MC Demographic?
Riedel thyroiditis, often due to systemic fibrosis.
MC demographic: middle-aged or elderly women.
How does hashimoto’s typically present?
- Diffusely enlarged, firm, finely nodular thyroid
- Usually just a “tight” feeling in the neck.
- Often complaints of hypothyroidism symptoms.
- More prone to depression even if labs WNL.
How does painless postpartum thyroiditis typically present?
- Some thyroid enlargement
- Transient hyperthyroidism after delivery
- Transient hypothyroidism after.
How does painless, sporadic thyroiditis present?
- 50% may have small, nontender goiters.
- Transient hyperthyroidism for a few months.
- Transient hypothyroidism for a few months.
How does subacute thyroiditis usually present?
- Acute enlargement of thyroid gland.
- Pain and dysphagia, usually referred to ear or jaw.
- Malaise and fever
- Hx of recent URI
- Short-term thyrotoxicosis followed by long hypothyroidism
How does suppurative thyroiditis usually present?
- Severe pain, tenderness, redness, fluctuance
- Associated fever
- Hx of immunosuppression
How does riedel thyroiditis often present?
- Assymetric, stony, adherent thyroid gland
- Associated dysphagia, dyspnea, pain, hoarseness
How do labs usually look for Hashimoto’s?
- Positive anti-TPO or anti-Tg antibodies
- Variable thyroid labs
- Sometimes have antibodies consistent with celiac disease.
How do labs usually look for subacute thyroiditis?
- Elevated ESR
- Low antithyroid antibody levels
- Variable thyroid labs
How do labs usually look for suppurative thyroiditis?
- Elevated ESR and leukocytes
- Normal thyroid and antibody labs
How do labs usually look for Riedel thyroiditis?
- Normal thyroid labs or variable.
Clinical
Which type of thyroiditis is strongly correlated with immunosuppression?
● Hashimoto thyroiditis
● Suppurative thyroiditis
● Subacute thyroiditis
● Riedel thyroiditis
Suppurative
Clinical
The underlying etiology of postpartum thyroiditis is:
● Systemic fibrosis
● A viral infection
● A bacterial or fungal infection
● An autoimmune process
An autoimmune process
What two conditions are anti-TPO antibodies usually positive in?
Hashimoto’s (95%)
Graves Disease (75%)
What two conditions are anti-Tg antibodies usually positive in?
- Hashimoto’s (70%)
- Graves Disease (55%)
How does Hashimoto’s appear on US?
Diffuse, heterogenous texture
What can an US help with regarding suppurative thyroiditis?
Presence of an abscess
What are the two main causes of hyperthyroidism and how can they be differentiated via US?
Graves Disease: increased vascularity
Thyroiditis: Normal or decreased vascularity
What diagnostic test besides US can help differentiate between Graves and thyroiditis?
RAI uptake scan
* Graves: increased uptake
* Thyroiditis: low uptake
What kind of diagnostic test can we run for a suspected suppurative thyroiditis?
FNA biopsy with gram stain and culture
What are the main complications associated with thyroiditis?
- Abnormal thyroid function
- Higher risk of depression
- Pressure on local neck structures
- Hashimotos: 1st trimester miscarriage risk
- Suppurative: abscess or chronic sinus tract formation
- Cancer: chronic thyroiditis
How do we manage Hashimoto’s thyroiditis?
- Hypothyroidism: replacement with levothyroxine
- Large gland/goiter: may try levothyroxine suppression therapy.
How do we manage subacute thyroiditis?
High-dose ASA or NSAIDs
Severe: iodinated contrast agents
BBs for symptoms.
How do we manage suppurative thyroiditis?
- ABX
- Surgical drainage of abscess
How do we manage Riedel thyroiditis?
- Tamoxifen and/or steroid therapy
- Surgery for decompression
Clinical
A patient has a nonspecific diagnosis of thyroiditis on her chart. Which type of thyroiditis would be most likely to have positive thyroid autoantibodies?
● Hashimoto thyroiditis
● Suppurative thyroiditis
● Subacute thyroiditis
● Riedel thyroiditis
Hashimoto’s
Clinical
A patient tells you that she had thyroiditis a few months ago, but it got much better with ibuprofen and a Medrol dose pack. Which type of thyroiditis is most likely to respond to these medications?
● Hashimoto thyroiditis
● Suppurative thyroiditis
● Subacute thyroiditis
● Riedel thyroiditis
Subacute thyroiditis
What is sick euthyroid syndrome?
State of abnormal thyroid function studies in the setting of severe nonthyroidal illness
Usually no prior hx of thyroid issues.
What is the suspected main cause of sick euthyroid syndrome?
Cytokines, especially: IL-6
What happens to thyroid hormone levels in sick euthyroid syndrome?
- Impaired deiodination of T4 to T3
- Decreased clearance of rT3
- Cytokine-based inhibition of thyroid hormone production
- Impaired accuracy of thyroid labs in severe illness
How do we manage sick euthyroid syndrome?
Observation unless history of previous thyroid condition.
Correcting the underlying disease is typically sufficient.
What characteristics make a thyroid nodule more likely to be cancerous?
- Large size
- Adherence to local structures
- Hoarseness or vocal cord paralysis
- LAN
What are the S/S of large, multinodular goiters?
- Swelling, hoarseness, dysphagia
- Retrosternal: dyspnea, facial erythema, JVD
What do thyroid nodules/goiters do to thyroid function?
- Hypo, nothing, or hyper.
What labs should we order for all patients with a thyroid nodule or goiter?
- TSH
- Sometimes: FT4, autoimmune labs
What can an US tell us regarding a thyroid nodule/goiter?
If it is part of a MNG or solitary.
Benign: Cystic lesions
What features of a thyroid nodule/goiter on US would make us concerned for possible malignancy?
- Irregular margins
- Solid lesions
- Heterogenous texture
- Abnormal vascularity
- Microcalcifications
- Large > 1cm
If a nodule appears cold after an RAI uptake, what does that suggest?
Little uptake = higher cancer risk.
What is the MC diagnostic test to evaluate a thyroid nodule for malignancy?
FNA Biopsy.
Can be done even if pt is on AC.
What is the criteria that indicates us to biopsy a solitary thyroid nodule?
- > 1 cm and suspicious appearance
- > 2cm
- Associated cervical LAN
- Growth
What do we do FNA biopsy for a MNG?
4 of the largest nodules that are > 1cm and any concerning ones.
If a nodule is >2cm but TSH is normal or just high, what treatment is recommended? Risks?
LT4 suppression.
Risks:
* Heart disease exacerbation
* Osteoporosis
* Hyperthyroidism
What are the general treatment options for a thyroid nodule/goiter?
- Thiourea drugs +/- BBs: s/s of thyrotoxicosis
- Surgery: cancerous nodules/goiters or toxic MNG
- Ethanol injection: shrinks benign nodules
- RAI therapy: toxic thyroid adenomas, toxic MNG, Graves
Clinical
You’re having a thyroid ultrasound done for a mass that was palpated on exam. Which statement from the sonographer would be most reassuring?
● “I see a few calcified areas.”
● “It looks like it’s filled with fluid.”
● “There is a lot of blood going to this nodule.”
● “It’s really hard to see the edges; they’re very irregular.”
It looks like it’s filled with fluid
Clinical
What treatment would be most effective to eradicate a 3-cm thyroid nodule with cells concerning for carcinoma on FNA biopsy?
● Radioactive iodine
● Surgical excision
● Levothyroxine suppression
● Methimazole, +/- propranolol
Surgical excision
What gender is thyroid cancer more prevalent in?
Women
What is the MC type of thyroid cancer?
Papillary thyroid carcinoma (80%)
How does papillary thyroid carcinoma typically present?
Single nodule that is slow-growing and confined to lymph nodes.
Usually autosomal dominant?
What are the 3 rarer kinds of thyroid cancers?
- Follicular thyroid carcinoma
- Medullary thyroid carcinoma
- Anaplastic thyroid carcinoma
All of these have high metastatic risk
What is the worst kind of thyroid cancer?
Anaplastic thyroid carcinoma
Highly aggressive, poor iodine uptake.
Classic: rapidly enlarging mass in a MNG.
Which thyroid cancer has high RAI uptake?
Follicular thyroid carcinoma.
What are the MC sites of thyroid cancer to metastasize to?
- Local lymph nodes
- Lung
- Bone
What symptoms can medullary thyroid carcinoma present with?
Flushing and diarrhea.
Can sometimes appear like Cushing’s.
How does a thyroid carcinoma feel on PE?
- Palpable
- Firm
- Nontender mass
Which thyroid carcinoma can present with hyperthyroidism?
Follicular thyroid carcinoma.
What thyroid carcinomas is serum Tg elevated in?
Metastatic papillary or follicular
What thyroid carcinoma is serum calcitonin and CEA elevated in?
Medullary thyroid carcinoma
Clinical
A patient newly diagnosed with thyroid cancer has not only abnormal thyroid function labs, but also abnormal levels of non-thyroid-related labs such as calcitonin and serotonin. What type of thyroid cancer is most likely?
● Anaplastic
● Medullary
● Follicular
● Papillary
Medullary thyroid carcinoma
What else can elevate CEA besides medullary thyroid carcinomas?
- GI cancer
- Breast cancer
- Lung cancer
- Pancreatic cancer
- Hepatobiliary cancer
When is a thyroid US more sensitive than CT/MRI for evaluating thyroid carcinomas? When are CT/MRI better?
- US: Evaluating for neck metastases
- CT/MRI: Distant metastases
What is the criteria for determining treatment for a thyroid mass?
- Is it cancer?
- How big is it?
What is the treatment for a >1cm cancerous thyroid mass? < 1cm?
> 1 cm: total thyroidectomy + cervical lymph node
< 1 cm: lobectomy if no other risk factors.
What is the surgical treatment for a < 4 cm indeterminate thyroid mass? > 4 cm?
< 4 cm: lobectomy
> 4cm: Total thyroidectomy
For postsurgical patients or non-surgical patients, what pharmacotherapy is indicated to manage differentiated thyroid cancer?
- Thyroxine suppression
- RAI therapy
What is the treatment for more aggressive thyroid cancers?
- Chemotherapy
- Local resection and radiation for anaplastic thyroid carcinoma. (unresponsive to RAI and other chemo)
How do we monitor for recurrence of thyroid cancer?
- Annual thyroid US
- Tg (if applicable)
- TSH
- RAI scan (if cancer was well-differentiated)
What thyroid cancer has the best prognosis? Worst?
Best: Papillary and follicular
Worst: Anaplastic
