Thyroid hormone provides negative feedback to the hypothalamus and pituitary to _______ secretion of _______
Decrease
TRH and TSH
____thyroidism feels more fatigue while ____thyroidism feels more agitated
Hypo
Hyper
What does USPSTF Grade I screening result tell you about?
Insufficient evidence to evaluate risk vs harm to screen for hormone dysfunction in non-pregnant asymptomatic adults
What it means in English: there is no reason to screen thyroid level in a normal healthy adult
What does USPSTF grade D say?
Recommend against screening for thyroid cancers in asymptomatic persons as risk outweighs benefit
T/F: goiters are only seen in patients with hypothyroidism
False; goiters can be present in both hypo and hyperthyroidism
Some goiter and thyroid nodules can cause _____ syndromes
Compressive
Meaning that it can compress the trachea, larynx, laryngeal nerves and esophagus
How do you assess thyroid function, what is the hormone that you are measuring?
TSH, which is produced in the pituitary
When you palpate a thyroid nodule or a goiter, what is the next thing you do/order?
Ultrasound to assess size, texture and nodularity
When do you do biopsy of a thyroid nodule?
When there is indication that the nodule may be malignant: such as microcalcifications, hypoechogenic and hypervascularity seen on ultrasound
If you see microcalcification, hypoechogenicity, and hypervascularity on an thyroid ultrasound, what is the next step?
Get a biopsy because these are malignant indicators
65 year old female complaining of fatigue, weight gain, anorexia, dry skin, cold intolerance, and constipation with some muscle cramps, likely _____
Hypothyroidism
They have slow bowel movements therefore constipation is a symptom
Clinically, a 65 year old who complains of fatigue, weight gain, dry skin and cold intolerance would have what findings on exam (signs)?
Non-pitting edema
Periorbital puffiness
Bradycardia
Decreased bp
Peripheral neuropathy
58 year old female comes in agitated, complaining of being too hot, heart beating too fast and bitching about her unexpected weight loss despite increased appetite, and pooping a lot. What is most likely going on with her?
Hyperthyroidism
Her GI sped up
Clinically, a 58 year old who feels hot and complains of palpitations and weight loss despite increased appetite, would have which findings on exam?
Warm, smooth, moist skin
Exophthalmos (if grave’s disease)
Increased systolic and decreased diastolic blood pressures
Tachycardia
Tremor
Increased reflexes
Hypothyroidism: ____ TSH, _____ reflexes
High TSH
Decreased DTRs
Hyperthyroidism: _____ TSH, _____ reflexes
Low TSH
Increased DTRs
When TSH comes back abnormal, what comes next?
Repeat TSH and also add free T4
Primary hypothyroidism has ______ TSH And _____ free T4
High
Low
Secondary hypothyroidism has ____ TSH and ____ free T4
Low
Low
Primary Hyperthyroidism has ____ TSH and _____ free T4
low
high
secondary hyperthyroidism has _____ TSH And ____ free T4
high
high
T/F: Central hypothyroidism is primary hypothyroidism
False; central refers to the CNS, so central hypothyroidism means that there is something wrong with either the pituitary (secondary hypothyroidism), hypothalamus (tertiary hypothyroidism)
Hashimoto thyroiditis is ____ hypothyroidism
Primary
What is subacute thyroiditis?
Asymptomatic, usually after a viral infection. Triphasic course: initially hyperthyroidism, followed by hypothyroid phase, and then recovery of thyroid function to the euthyroid range
Hashimoto thyroiditis autoimmune antibodies:
HLA-DR3
HLA-DR5
Anti-TPO or Anti-TG in serum
T/F: Hashimoto antibodies and CD8 T cells usually destroy the thyroid slowly over months to years and CD4 secretes inflammatory cytokines
True
Iodine excess may result from medications like Amiodarone and betadine, and this would lead to ______
basically it could lead to both hypothyroidism and hyperthyroidism
What is Wolff-Chaikoff effect?
Too much excess iodine causing obstruction of the binding and incorporation of iodine into the hormone caused by large doses of iodine
Hypothyroidism
What is Pendred syndrome?
A genetic disorder that causes hearing loss but can also affect the thyroid gland leading to hypothyroidism
Congenital causes of hypothyroidism can lead to ______
Failure to thrive
What is Riedel struma?
A chronic form of thyroiditis (hypothyroidism) due to infiltration by IgG secreting plasma cells.
Potential causes of central hypothyroidism:
Pituitary adenoma and other tumors
Pituitary hemorrhage
Sheehan’s (postpartum pituitary ischemia)
Iatrogenic (radiation/ drugs)
Infectious/inflammatory
Infiltrative
Trauma
A 30 year old postpartum female, complaining of tunnel vision, fatigue, cold intolerance, think ______
Secondary hypothyroidism- likely a tumor on the pituitary, even more so likely it is Sheehan syndrome
Hypothalamic dysfunction would have these symptoms:
Temperature regulation
Appetite change
Other hormonal dysfunction signs and symptom
If suspect central hypothyroidism, what imagining should you order to evaluate for hypothalamic-pituitary tumor
MRI of the region
What is myxedema coma?
Severe undiagnosed or untreated hypothyroidism from any cause
Triggered by a physical stress
Symptoms of myxedema?
altered mental status
Hypothermia
Bradycardia
Hyponatremia and hypercarbia
Cardiomegaly, pericardial effusion, cardiogenic shock and ascites/edema may be presents
T/F: status post an acute or severe illness or surgery, it is likely to develop a reversible thyroid condition called euthyroid sick syndrome
True; thyroid function tests not necessary in non-thyroid illness
If anti-thyroid peroxidase, and anti-TG antibodies come back positive, this is indicative of ______
Hashimoto thyroiditis
Graves disease, ____ antibodies would be elevated
TSI (TRab- thyroid autoantibodies)
What is subclinical thyroid disease?
abnormal TSH level, but Free T4 is often normal
Patient is asymptomatic
Meaning some functional thyroid intact, responding to the feedback loop
T/F: Subclinical thyroid disease and Subacute thyroiditis are the same thing
False; subacute thyroiditis is triphasic thyroiditis after a viral infection, and subclinical thyroid disease is elevated TSH with normal free T4. Both are asymptomatic
Most likely etiology of hypothyroidism:
Hashimotos thyroiditis
Patient with recurrent miscarriages with or without infertility, use this test:
Anti-TPO antibody
T/F: to diagnose hashimoto, must confirm with the Anti-TPO antibody?
false; most cases of primary hypothyroidism are due to hashimotao, the current recommendation is to initiate treatment without further testing
What is the treatment plan for subclinical hypothyroidism?
Watchful waiting to see if free T4 is decreasing in like 6 month, this would suggest that the thyroid is starting to malfunction
T/F: pharmacologic therapy is not recommended to treat subclinical hypothyroidism
True; because you don’t want to shut down the thyroid gland, especially if TSH is <10.
Thought if consistent elevation of TSH >10, then maybe can give levothyroxine
Contrast hyperthyroidism vs thyrotoxicosis
Hyperthyroidism (RAIU >30%) is a state of thyroid hormone excess due to thyroid gland overactivity
Thyrotoxicosis (RAIU <10%) a state of thyroid hormone excesss that may or may not be of thyroid gland origin, maybe an external/ exogenous cause
RAIU >30% is suggestive of ______, and RAIU of <10% is _______
Hyperthyroidism due to increased thyroid function (taking in more radioactive iodine)
Not associated with increased thyroid function - thyrotoxicosis
Graves disease would have this appearance on radionuclide scans:
Diffuse homogenous iodine uptake
If there is an isolated uptake of iodine of radionuclide scans, what does it mean?
an adenoma
Subacute thyroiditis would have RAIU _____ than normal thyroid RAIU
Less uptake than normal
Exophthalmos is suggestive of _______
Graves disease
HLA-DR3, HLA-B8, TSH receptor autoantibodies is this autoimmune disease:
Graves disease
What is the antibody that is indicative of Graves disease?
TSH receptor autoantibodies (Trab)
HLA-DR3, HLA-B8
Weight loss, heat intolerance, goiter, pretibial myxedema are signs and symptoms consistent with ______ disease
Graves
Exophthalmos may also be present
Thyroid hormone exposure (exogenous source) would have _____ free T4 and ____ TSH
Increased
Decreased
T/F: diet supplements often contain much iodine, which could potentially lead to hypothyroidism
False; diet supplement usually contain T3/T4, which taking it could cause hyperthyroidism
What are examples of ectopic thyroid tissues?
Struma ovarii- ovarian teratoma comprised of throud tissue which secretes thyroid hormone
Metastatic follicular thyroid cancer
What is struma ovarii?
Ovarian teratoma comprised of thyroid tissue which secretes thyroid hormones
A hyperthyroidism that is not caused by thyroid gland overactivity
T/F: Lithium and iodide inhibits thyroid hormone release. Patient treated with lithium may actually develop hypothyroidism and thyrotoxicosis can also occur
True
Postpartum thyroiditis have transient _____ free T4 and ____ TSH
High free T4
Low TSH
Hyperthyroidism patient should avoid substances that may worsen agitation and metabolic stress, ie______
Caffeine
Excess sugar
Stimulant medication or drug such as cocaine or pseudophedrine
