Thyroid Disorders Flashcards
What are the levels (high/low) of the flowing hormones in primary hypothyroidism? Hyperthyroidism?
TSH, T4, T3
Hypo:
TSH: High T4: low T3:low
Hyper:
TSH: low T4: high T3: high
Goiter
What is it?
What is the most common world wide cause?
What are common causes in the US?
- abnormal growth of the thyroid gland
- worldwide, Iodine deficiency is the most common cause
- In the US, common causes are mulitnodular goiter, Hashimoto’s thyroiditis, graves disease
Sx of obstructive goiter
- monotone voice
- dysphagia
- tracheal compression
Goiter
-dx
- clinical hx and exam
- Obtain TSH
- -If high, measure serum free T4= hasimoto’s thyroiditis
- -If low, measure T4 and serum total T3= multinodular goiter/ grave’s disease
Hypothyroidism
-epidemiology
Epidemiology
- women, increasing with age
- most common cause is Hashimoto’s Thyroiditis
- three types- Primary, Secondary, Tertiary
Causes Hypothyroidism
- Primary
- Secondary
- Tertiary
Primary
- Iodine deficiency
- Autoimmune: Hashimoto’s
- Iatrogenic: Iodine-131 therapy, thyroidectomy
- Post Partum Thyroiditis
- Drug induced: Lithium, amiodarone, antithyroid drugs
- Congential: agenesis, dysgenesis, hypoplastic
- Adult onset: normal aging
Secondary
- Neoplasm
- Surgery
- Post partum necrosis
- Cushings
- Radiation
Tertiary
- Hypothalamus dysfunction
- Hemochromatosis
- Sarcoidosis
Hypothyroidism
Signs and Symptoms
dx
tx
History: fatigue, cold intolerance, weakness, lethargy, weight gain, constipation, myalgias, arthralgias, menstrual irregularities, hair loss
Physical findings: Dry, coarse skin, hoarse voice, brittle nails, periorbital, peripheral edema (myxedema), delayed reflexes, slow reaction time, bradycardia
dx
- TSH: elevated
- free thyroid hormone: depressed
- can have sub-clinical hypothyroidism where T3 and T4 are within normal limits but TSH mildly elevated (at risk: women, elderly, other autoimmune diseases)
tx
- Levothyroxine (T4) (Synthroid)
- should be taken on an empty stomach, monitor response
- given even to pts with subclinical hypothyroidism
How to measure thyroid function in pts with:
- an intact hypothalmic-pituitary axis
- pituitary insufficiency
- an intact hypothalmic-pituitary axis: follow with serial TSH measurements
- pituitary insufficiency: measurements of free T4 and T3
each for 6-8-12 weeks
Hashimoto's Thyroiditis aka associated with what is it precipitating factors sx dx tx
aka
-Chronic Lymphocytic Thyroiditis
associated with
-non-Hodgkins lymphoma
what is it
-autoimmune disorder believed to have a genetic basis w/ environmental factors
precipitating factors
-Infection, stress, sex steroids, pregnancy, radiation exposure
sx
- painless goiter
- fatigue
- muscle weakness
- weight gain
- feeling of fullness in the throat
- neck pain, sore throat, or both, low grade fever
dx
- TSH, Free T4
- TPOAb (anti-thyroid peroxidase antibody)
- TGAB (anti-thyroglobulin antibodies)
- ultrasound
- radioiodine uptake
tx
- thyroid hormone replacement, levothyroxine
- monitoring of TSH is best and most reliable
Myxedema
sx
tx
- thought to be related to connective tissue proliferation in reaction to increased TSH levels
- pt usually has a hx of hypothyroidism
sx
- droopy eyelids
- lethargy, fatigue, mental sluggishness
- decreased reflexes
- mucopolysaccharide infiltration of the dermal space causes: facial puffiness, periorbital edema, non-pitting pretibial edema*
tx
- Levothyroxine
- monitor TSH
Hyperthyroidism
AKA
epidemiology
causes (common, less common, rare)
AKA
-Thyrotoxicosis or Toxic diffuse goiter
epidemiology
-women ages 20-40
causes
common-Graves disease*, toxic adenoma, toxic multinodular goiter
less common-subacute thyroiditis, Hashimotos thyroiditis with transient hyperthyroid state, postpartum thyroiditis
rare-struma ovarii, hydatiform mole, TSH secreting tumor
*Hyperthyroidism that cannot be correlated to the endocrine system is usually a malignancy
Hyperthyroidism
sx
dx
tx
sx
- nervousness, heat intolerance, diaphoresis, palpitations, fatigue, weight loss, frequent bowel movements
- tachycardia, goiter, skin changes (pretibial myxedema), tremor, eye signs (exophthalmus, extraocular muscle dysfunction), lid lag, osteoporosis
dx
- TSH-low
- Free T4- High
- radioactive iodine uptake
tx
- Anti-thyroid drugs (thioamides) such as Methimazole or Propylthiouracil
- radioactive iodine tx (most recommended)(most commone SE is hypothyroidism)
- surgical removal
- can give beta-blockers (Angie’s Propranolol) for symptoms for pts with temporary form of hyperthyroidism
Grave’s Disease
- what is it
- tetrad of sx
- other sx
- dx
- tx
what is it
-organ specific autoimmune disorder. The body creates circulating antibodies (thyroid-stimulating immunoglobulin TSI) and directs TSI toward the follicles of the TSH receptor. TSI acts as a TSH-receptor AGONIST (activates thyroid hormone synthesis and release and thyroid growth)
Tetrad of sx
- NONTENDER, smooth, symmetric thyroid enlargement
- Thyrotoxicosis- hyperthyroid state
- exophthalmosis
- pretibal myxedema
Other sx
- extremely thin digits
- excess sweating
- older people may have hyperthyroidism: flat affect, weight loss, emotional lability, A fib, CHF, muscle weakness
dx
- TSH: low
- T4: high
- TSI
- RAIU (radioactive Iodine Uptake)
tx
- Antithyroid drugs (Propylthiouracil and Methimazole)
- Beta blockers
- Radioactive Iodine
- Surgery
Multinodular Goiter (“Plummers Disease”)
- characterized by what
- caused by
- Characterized by functionally autonomous nodules
- caused by hyperplasia of the follicular cells whose activity becomes independent of TSH
Factitious Hyperthyroidism/Thyrotoxicosis factitia
- caused by
- what happens to T4, T3, and TSH
- caused by ingestion of levothyroxine by euthyroid patients (usually an attempt to lose weight)
- T3 and T4 go up, TSH goes down
Thyroid Storm
- Precipitating factors
- clinical features
- dx and tx
EMERGENCY
Precipitating factors
- hyperthyroidism
- stress
- infection
- diabetic ketoacidosis
- trauma
- manipulation during thyroidectomy
Clinical features
- Very high fever
- CV events
- CNS effects
- N/V
dx and tx
- RAPID
- peripheral cooling
- replace fluids, glucose, electrolytes
- propranolol to block effects of T4 on CV function
- Glucocorticoids to correct adrenal insufficiency and to inhibit peripheral conversion of T4 to T3
- Propythiouracil (PTU) and Methimazole (Tapazole) to block thyroid synthesis
How to distinguish Thyroditis
Usually presents clinically as hyperthyroidism due to leakage of preformed thyroid hormone but most patients ultimately develop hypothyroidism.
-Can be distinguished from other causes of thyroiditis as the RAIU (radioactive iodine uptake) is low
Acute Thyroiditis complication of what sx dx tx
- septicemia
sx
-fever, redness of the skin over the thyroid and TENDERNESS of thyroid
dx
-if blood cultures are negative, aspiration of the thyroid gland may be be tired to identify the organism
tx
-IV abx, occasionally I and D of the gland
Subacute Thyroiditis secondary to what sx dx tx
-viral infection
sx
- fever and anterior neck pain*
- exquisitely tender thyroid gland
dx
- ESR: high
- thyroid scan shows little or no uptake of radioiodine
tx
-symptomatic
Postpartum (subacute lymphocytic thyroiditis) onset resolution sx tx
- onset occurs within 3-12 months post delivery
- eventually resolves (could take months)
sx
- NONTENDER thyroid gland
- low RAI uptake
tx
- propranolol for tremors and tachycardia
- if hypothyroidism develops, levothyroxine
Other types of Thyroiditis
Iodine-induced- induced by contrast agents for aniography or CT
Amiodarone induced- Iodinated drug with antiarrhythmic and antianginal properties
Riedels Struma (invasive fibrous thyroiditis)- a type of chronic thyroiditis. seen in middle aged women. Gland is stony hard and adherent to surrounding structures, may cause sx of compression (dysphagia, dyspnea, hoarseness). Treat with chemo and steroids for inflammtion
What is the most common endocrine problem in the US?
Thyroid nodules!!
Thyroid nodules
most often ____ neoplasms from _____ _____
typically how many?
pain or no pain?
most often benign neoplasms from follicular epithelium
- usually solitary
- often painless, often discovered during a routine physical exam
- most pts have normal thyroid function
- appears COLD on RAIU
Features that favor a BENIGN thyroid nodule
- FH of Hashimotos
- FH of benign thyroid nodule
- sx of hypothyroidism or hyperthyroidism
- pain or tenderness associated with nodule
- soft, smooth, mobile
- multinodular without prominent nodule
- “warm” nodule of thyroid scan
- simple cyst on ultrasound
Thyroid cancer
- sx
- dx
- types and tx
sx
-painless swelling in the region of the thyroid
dx
- thyroid function test are normal
- dx made by fine needle aspiration cytology
Types
- Papillary (most common): tx is thyroidectomy with RAI
- follicular: tx is same as papillary
- medullary: calcitonin is a unique tumor marker for this, tx is surgical removal
- anaplastic (least common)
–Hurthel cell: very rare, classified as follicular thyroid cancer, can be benign or malignant, tx is surgical removal
Hypo vs hyperthyroidism
Hypo- dry coarse hair, loss of eyebrow hair, puffy face, enlarged thyroid (goiter), slow heartbeat, weight gain, constipation, brittle nails
-arthritis, cold intolerance, depression, dry skin, fatigue, forgetfulness, heavy menses, infertility, muscle aches
Hyper- hair loss, bulging eyes, sweating, enlarged thyroid (goiter), rapid heartbeat, weight loss, frequent bowl movements, warm/moist palms, tremor, soft nails
-difficulty sleeping, heat intolerance, infertility, irritability, muscle weakness, nervousness, scant menses
