Thyroid Gland Flashcards
Thyroid gland produces and secretes two hormones
Tri-iodothyronine (T3)
Thyroxine (T4)
What do the thyroid hormones regulate
Positive inotropic (increase myocardial contraction force)
Positive Chronotropic (Increase HR)
Increase metabolism
Increase body temperature
Increase secretion of growth hormone
Normal thyroid function
hypothalamus releases thyroid-releasing hormone (TRH)
stimulates pituitary gland to produce and release thyroid-stimulating hormone (TSH).
TSH causes thyroid to make t4 and t3
When T3 and T4 levels increase, they prevent release of
TRH and thus TSH
What happens when T3 and T4 levels drop
Hypothalamus releases TRH stimulating TSH stimulating prodction of T3/T4
Function of thyroid gland
Absorb iodine and amino acid tyrosine to create t3/t4
How much iodine needed per week from diet
1mg/week
T4 vs T3
T4 is mainly inactive in the body, unable to affet cells until it is converted into t3 which can enter cells
Examples of iodine rich food
- Kelp
2 Yogurt
3 Cows milk
4 Strawberries
5 Mozzarella cheese
6 Iodized salt
Hypothyroidism primary reason
Thryoid disorder
Most common cause of hypothyorididsm
Hashimotos Thyroiditis.
autoimmune - body attacks thyroid reduceing it’s funciton
Hypothyrdism results form
hashimotos disease
Surgical removed
Overtreatment of hyperthyoidism
Goiter often caused by insufficient iodine
SS of hypothyroidsm
Wt gain (decrease metab)
Fatigue
Cold intolerance
Course dry hair
Dry rough pale skin
Muscle cramps/weakness
Constipation
Depression
Irritability
Hypothyroidism will cause TSH to be
High, bc it senses decrease in T3/T4 and tries to stimulate thyroid to produce more
If thyroids are not working properly and left untreated in new borns this could affect
Brain development
- thyroid replacement therapy started within 6 wks as tx
Cretinism
Congenetial
- Neonate appears normal at birth but cant producce T3/T4 i
- if not treated, child will have profound developmental deficiets
Myxedema
Myxedema (acquired in late childhood, early adulthood) – characterized by slowing of metabolic processes, mucous accumulation in connective tissues
Lab tests for hyperthyroidsm
High T3/T4
General SS of hyperthyroidsm
Increased metabolic rate
Wt loss
Increased body temp
Heat intolerance
Insomnia
Tachycardia
HTN
Exothalmus: Bulging of eyes (immune system attacks muscles and fatty tissue around the eyes
Graves disease
Autoimmune disorder causesing antiobodys to bind to and stimulate TSH receptor on thyroid
Hyperthyroidism
Palpitations
Diarrhea
Nervousness
Irritability
Tcardia
Altered menstrual flow
Sleep disorders
Diseases causing hyeprthyroidsm
Graves
Plummers diseaes (Usually benign tumor on thyroid)(
Thyroid storm (Caused by infections, glucose changes, recent surgery on gland, trauma, withdrawl from antithyroid hormones)
- High mortality
Tests for thyroid disorder
Tests for presence of antibodies
(Graves and Hashimotos)
Fine needle biospy - cancer
Ultrasonography
CT scan, MRI
Radioactive iodine uptake test
Tx hypothyroid disorder
Replace missing T3 and T4 with levothyroxine (T4)
Therapy initaited ASAP
Serum TSH should decrease in response
Levothyroxine (Synthroid Uses
T4 replacement
Increases metabolic rate
thereby increasing oxygen
consumption, respiration, and heart rate
Increases rate of fat protein and carb metabolism
Promotes growth and maturation
Is T3 given?
No, just T4, since it is converted to T3
When would Levothyroxine be used
Thyroidectomy
Surgical removal of the thyroid gland
Radiation or antithyroid drugs
Congenital defect
Management of thyroid cancer
Treatment of coma related to myxedema
Given in morning at same time every day on EMPTY stomach to work effectively
AE of levothryoxine
Overexxpression of T3/4
CNS excitiablitliuy
Tremors
Insomnia
D/V
TCardia - Cardiac arrest
Assessment during levothyroxine therapy
Obtain baseline ECG AND LFTs
What serum levels and other signs to monitor for someone recieving T4
Monitor VS for sudden increases (indicating toxic levels of Thyroid hormones)
Monitor for wt loss and signs of hyperthyroidism
monitor serum levels: T3/4, TSH, and BG
Hyperthyroidism INCREASES blood glucose
What does hyperthroidism due to BG
Increases BG levels
Hyperthyroidism requires what sort of nutrition
HJigh calorie diet
6 full meals with snacks
Caffeien to be avoided
Two major tx of hyperthyroidism
Radioactive Iodine
- Reducing T3/4 production
Antithyroid drugs
PTU (Propylthiouracil )
Tx of hyperthyroidism caused by overproduction of thyroid hormone
Establishes normal thyroid state prior to sx or radioactive iodine tx
Palliative tx of toxic nodular goiter
Does not effect already synthesised hormones
AE of PTUq
Leukopenia, myelosuppression
Hypersensitivity reactions, rash, urticaria
Arthralgia, joint swelling
Glomerulonephritis
Headache, vertigo, neuritis, paresthesia
Nausea
Serious adverse effects
Aplastic anemia
Liver impairment
WHat to know abt thyroid meds
NEVER stop taking thyroidism (Hyperthyroid meds) suddenly
- Body depends on this
TSH high suggests that thyroid is producing TOO much and vis versa
