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
