Thyroid Flashcards
What shape is thyroid and location
Butterfly shape. Located in middle of neck
Any protein bound to a hormone is
Inactive
Parathyroid location
Embedded in the posterior aspect of the thyroid
Parathyroid gland secretes which hormone
PTH. Parathyroid hormone
PTH regulates what
Calcium & phosphate levels
What is necessary for PTH function
Vitamin D
Hormones are what kinds of messengers & how are they transported?
chemical; transported by the blood stream
thyroid c-cells produce
calcitonin
thyroid follicles (sac structures) function
remove iodine from blood to make thyroid hormones
If the serum calcium level drops….PTH will increase or decrease
PTH will increase to get more circulating calcium
Regulation of Thyroid in order
Body stimulus–>Hypothalamus:TRH–>Anterior Pituitary:TSH–>Thyroid Glad:Thyroid Hormone
Thyroid Hormone
T3 & T4
Things that will make us have an increase in thyroid hormone
Cold environment, Hypoglycemia, high altitude, pregnancy
Anterior pituitary gland produces?
TSH
Thyroid Hormone regulates
metabolic rate
Thyroid Hormone increases?
protein synthesis, carb & fat metabolism, oxygen consumption, bone growth
Thyroid Hormone is necessary for
growth & mental & sexual development
Difference between T3 &T4
T4 has 4 atoms, T3 has 3 atoms. T3 is more powerful, T4 is more prevalent
TSH normal values
2-10 mU/ml
Secondary hypothyroidism is related to
pituitary problems
FT value
1.0-2.3 ng/dL
T4 value
5-12 mcg/dL
FT what kind of hormone
unbound to protein, active hormone
hyperthyroidism = High or Low TSH
Low TSH
T3 Values
80-200 ng/dL
When people develop thyroid antibodies they can develop
graves disease, Hashimoto’s thyroiditis, chronic thyroiditis
Who can get thyroid antibodies?
people with viral infections
An RIA ( radioactive iodine uptake) test
They inject or give this PO & look to see how the thyroid takes it up. Any iodine in the system the thyroid will take
warm spots taking up less radiation
benign lesions
cold spots taking up less radiation
Malignant tumor
What is the DR looking for if he does a thyroid biopsy?
cancer
3 alterations in thyroid function
hyperthyroidism (excess thyroid hormone); hypothyroidism (low thyroid hormone); Goiter (increase in thyroid size)
euthyroid
normally functioning thyroid
Hyperthyroid signs
everything is going to speed up. Tachycardia, anxiety, restlessness, fatigue (bc their working so hard), menstrual changes, negative nitrogen balance, weight loss
Exophthalmos
forward protrusion of eyeball; sclera visible above iris (might need surgery to fix this)
Ophthalmopathy
related to hyperthyroidism; TSA interacts with orbital tissue behind the eyeball & the extraoccular muscles that move the eyeball (bulging of eye), they can get blurred vision, eye pain, exophthalmos
Effects of Exopthalmos
eye dryness, irritation, infection& ulceration bc eyelids can not close over protruding eye
Pretibial myxedema
form of graves disease which is a form of hyperthyroidism. Plaques & nodules forming over legs & feet.
hyperthyroidism lab values
TSH decreased everything else increased
causes of hyperthyroidism?
Graves Disease, Toxic multinodular goiter, pituitary neoplasm, Thyroiditis, Tyroid Storm, Increased iodine ingestion
Graves disease
most common hyperthyroidism, autoimmune disorder, increase in iodine intake can contribute to this. TSA binds to TSH which increases thyroid production
Toxic Multinodular goiter
They have little nodules on the thyroid which secrete thyroid hormone, gradual onset, no opthalmopathy,
Pituitary neoplasm
Pituitary tumor stimulates thyroid to synthesize thyroid hormone.
who is at risk for toxic multinodular goiters?
elderly females c a history of goiters get this
What form of hyperthyroidism is pituitary neoplasm?
Secondary
Thyroiditis
inflammation of thyroid gland, can happen with any viral infection, acute disorder with increased TH secretion
If a person has thyroiditis chronically, they can develop a
hypothyroid state
Thyroid crisis/storm
extreme state of hyperthyroidism. When a person already has hyperthyroidism & they don’t know it & they get a viral infection or have stress
What things can cause thyroid crisis/storm in People who have hyperthyroidism
Stress: trauma, infection, pregnancy, co-morbidities or meds, not being treated, manipulation of thyroid gland surgery
s/s of thyroid crisis/storm
tachycardia, CHF, angina, MI, atrial fib, systolic hypertension c wide pulse pressure, agitation, restlessness & tremors, confusion, psychosis, delirium, sezures, coma, abdominal pain, vomiting, bone loss fracture, life threatening
Thyroid crisis/storm treatment
supportive therapy, respiratory support, treat hyperthermia by using cooling blankets & acetaminophen, IV fluids, hemodynamic support by vassopressors to restore or maintain bp & digoxin & diuretics to treat CHF
Adrenergic blockers- propranolol (Inderal)is given to a patient with thyroid crisis/storm in order to?
to slow the hr down, its not to correct hyperthyroidism. it is given to prevent any cardiac problems
Anti-thyroid medication is started for a patient with thyroid crisis/storm because it?
inhibits hormone synthesis but doesn’t block any thyroid hormone that’s already in the gland &partially inhibit conversion of T4 to T3
Why do we do plasmapheresis or peritoneal dialysis on a patient with thyroid crisis/storm?
to remove circulating antibodies
Treatment of hyperthyroidism depends on what
patient age & physical state, & the case of the hyperthyroidism
Treatment of hyperthyroidism
medications, Radioactive iodine therapy or surgery
Medications to treat hyperthyroidism
iodine solutions, Antithyroid agents (thioamides); Beta-blocker: Inderal
Iodine Solutions: Lugols solution, Potassium Iodine (SSKI)
prevent the synthesis & release of TH. Its a short term effect
When are Iodine Solutions: Lugols solution, Potassium Iodine (SSKI) used & why?
Used in thyroid crisis/storm hastens effect of antithyroid meds, the iodine decreases vascularity of the thyroid gland which decreases the release of TH. Its used prior to surgery
Antithyroid agents (thioamides) examples & are given when?
Propylthiouracil (PTU) & Methimazole (Tapazole); given during thyroid crisis/storm
Propylthiouracil (PTU) effects
N&V, crosses placenta & breast milk in low concentrations, onset 10-21 days c peak effect 6-10 weeks
Methimazole (Tapazole) effects
Bone marrow suppression, agranulocytosis, anemia, leukopenia, crosses placenta & breast milk
Radioiodine Therapy
Thyroid takes up radioactive iodine which will kill follicle cells in the thyroid gland which will then cause the thyroid gland to produce less TH, can be given orally, no hospitalization & no radiation precautions, Cant do if pregnant
Why would radioiodine therapy cause a patient to go on thyroid hormone replacement?
because you could send them into a hypothyroid state because you don’t know how much radioiodine they need
Dr will do Thyroidectomy if
drug therapy fails, Radiation therapy contraindicated, or patient has thyroid cancer
With a Partial thyroidectomy, does patient need Thyroid replacement therapy?
no thyroid replacement is necessary. A partial thyroid can supply adequate TH
thyroid follicles function
remove iodine from blood to synthesize thyroid hormones
Lithium & Potassium can cause
secondary hypothyroidism
Secondary hypothyroidism
something is wrong with the pituitary
Primary hypothyroidism
something is wrong with the thyroid
Aspirin, steroids, dopamine, heparin & antithyroid therapy can cause
primary hypothyroidism
cortisone, thorazine, Dilantin, heparin, sulfonamides, reserpine, testosterone, Inderal, orinase & high doses of salicylates may increase or decrease TH
decrease
What do you want to avoid prior to thyroid test
shellfish, no fluid restrictions
oral contraceptives, estrogen, clofibrate & trilafon may increase or decrease TH
increase
Graves disease, Hasimotos thyroiditis, chronic thyroiditis all have what?
thyroid antibodies
