what are the actions of thyroid hormone?
- stimulates energy (metabolic energy)
- heart rate and force of contractions
- growth and development of the nervous skeletal system
what is the difference between T3 and T4?
T3 - 20%, more active, and more potent
T4 - 80%, breaks down into T3
what does thyroid hormone release?
T3, T4, calcitonin
what does calcitonin do?
regulates calcium in the blood
where does thyroid regulation begin?
hypothalamus
what is primary hypothyroidism?
caused from risk factors, exposure, the environment, food, and radiation for treatment for hyperthyroidism
what is secondary hypothyroidism?
malfunction in the feedback loop, endocrine issue
what does goitrogenic mean?
food that can affect thyroid function by inhibiting the synthesis of thyroid hormones
- blocks absorption of TSH
- inhibit the release of TSH
what are examples of goitrogenic foods?
- soy
- red wine
- strawberry
- green leafy vegetables
what are the signs and symptoms of hypothyroidism?
- intolerance to cold
- extreme fatigue
- slow metabolism
- dry skin
- metabolism
- decrease heart rate
- pale and lethargy
what would happen if a patient is receiving too much Synthroid?
they would have opposite symptoms - hyperthyroidism
what is myxedema?
full-blown hypothyroid syndrome
what is endemic?
lack of iodine in the diet
what is a goiter?
irregular growth of the thyroid gland
what are the three types of goiters?
- simple
- endemic
- sporadic
what is a simple goiter?
the thyroid gland doesn’t make enough hormone therefore the thyroid hormone needs to work harder and it grows
what is an endemic goiter?
lack of iodine in the diet
what is a sporadic goiter?
typically a side effect of a drug (an example would be lithium which is psychiatric med)
what is the drug of choice for hypothyroidism?
levothyroxine (Synthroid)
how should levothyroxine (Synthroid) be taken?
- usually given PO once daily, on empty stomach with no food for 1/2 hour afterward
- if taken with food the effectiveness decreases so you would need a higher dose
- stay consistent either with or without food
what is the normal dose for levothyroxine (Synthroid)?
50-150 mcg
how long does it take for levothyroxine (Synthroid) to reach a therapeutic level? why?
1 month - T4 half-life is 1 week that is why you get your blood checked after 1 month
how often should levothyroxine (Synthroid) be taken?
once per day
what is levothyroxine (Synthroid) made of?
synthetic T4 - don’t need to take T3 because the T4 will become T3
what is a rare but serious side effect of levothyroxine (Synthroid)?
arrhythmias
what does levothyroxine (Synthroid) decrease the effectiveness of?
- GI absorption
- Dilantin, Tegretol, and Zoloft - accelerates absorption
- digoxin and insulin
what does levothyroxine (Synthroid) increase the effectiveness of?
Coumadin
what route can levothyroxine (Synthroid) be given?
PO and IV for myxedema coma
what are the signs and symptoms of hyperthyroidism?
- increased heart rate
- increased energy level
- diarrhea
- sweaty
- weightloss
what is a common medication used for hyperthyroidism?
beta-blockers like propranolol
what is the most common cause of hyperthyroidism?
grave’s disease
what are some causes of hyperthyroidism?
- inflammation
- increased iodine in the diet
- grave’s disease
what is exophthalmos?
bulging eyes caused by hyperthyroidism/grave’s disease
what is the treatment for exophthalmos?
glucocorticosteroids
why is thyroid storm?
severe and life-threatening hyperthyroidism
what are the signs and symptoms of thyroid storm?
- severe tachycardia
- severe agitation
- possible LOC
- death
- tremors
- heart failure
- coma
what are 4 treatment options for hyperthyroidism?
- propylthiouracil (PTU)
- methimazole (tapazole)
- nonradioactive iodine
- radioactive iodine
what is the normal range for TSH?
0.3-6
is TSH increased or decreased with hypothyroidism?
increased
is TSH increased or decreased with hyperthyroidism?
decreased
are T3 and T4 increased or decreased with hypothyroidism?
decreased
are T3 and T4 increased or decreased with hyperthyroidism?
increased
what is the TSH value for hypothyroidism?
greater than 6
what is the TSH value for hyperthyroidism?
less than 0.3
what is the action for propylthiouracil (PTU)?
inhibits the conversion of T4 and T3 - reduces T3
what is propylthiouracil (PTU) used for?
- severe hyperthyroidism or thyroid storm
- preparation of thyroid gland prior to surgery or radioactive treatment
what is the advantage of propylthiouracil (PTU)?
takes effect quickly
what is a rare but serious side effect of propylthiouracil (PTU)?
agranulocytosis
what is the action of methimazole (Tapazole)?
suppresses the synthesis of thyroid hormone
what is the difference between methimazole (Tapazole) and propylthiouracil (PTU)?
methimazole (Tapazole) is then times more potent than propylthiouracil (PTU) but works more slowly
- methimazole (Tapazole) is preferred use for pregnancy and breastfeeding
what is methimazole (Tapazole) used for?
hyperthyroidism and prior to surgery or radioiodine
what is the dosing like for methimazole (Tapazole)?
once a day
what is the adverse effect of methimazole (Tapazole)?
agranulocytosis
what is nonradioactive iodine used for?
used for rapid treatment for hyperthyroidism
- alternative to surgery
what is the action of nonradioactive iodine?
reduces gland vascularity and suppresses thyroid
- basically makes some of the thyroid inactive
how is nonradioactive iodine administered?
administer PO as a strong iodine solution (SSKI) or Lugol’s solution
- also can be given IV for thyroid storm
what is the action of radioactive iodine (131-1)?
destroys thyroid tissue to treat Grave’s disease (hyperthyroidism)
what are the advantages of radioactive iodine (131-1)?
- exposes only the thyroid tissue to altering radiation
- eliminates the surgical risk
- allows for outpatient treatment
what can radioactive iodine (131-1) cause?
may induce delayed hypothyroidism and that will be lifelong
what does the parathyroid hormone regulate?
calcium levels in the blood
what triggers the release of parathyroid hormone regulate?
decreased calcium
what inhibits parathyroid hormone?
hypercalcemia
what does hypoparathyroidism manifest as?
hypocalcemia
what are the signs and symptoms of hypoparathyroidism?
hypocalcemia - tetany, muscle spasms, and convulsions
what is hypoparathyroidism caused by?
surgical removal
what does PTH activate?
vitamin D, which promotes the absorption of calcium in diet and bones and reduces excretion in kidneys
what is the normal level of calcium in the blood?
10.5mg/deciliter
what are the signs of hypocalcemia?
chvostek’s signs and trousseau’s sign
what is the treatment for hypoparathyroidism?
- PTH can’t be given as medication
- you can treat the hypocalcemia with calcium replacement agents and Calcitrol (Vitamin D3)
what are the signs and symptoms of hyperparathyroidism?
- hypercalcemia
- decalcification of bones
- deposition of calcium deposits in body tissue
- weakness
- lethargy
- bone abnormalities
what can cause hyperparathyroidism?
- parathyroid adenoma
- CKD especially in dialysis patients
- malabsorption by intestines
what two drugs are used for the treatment of hyperparathyroidism?
- cinacalcet
- calcitonin
what is the action of cinacalcet?
treatment for hyperparathyroidism
- decreases secretion of PTH and normalizes serum Ca
what teaching is needed with cinacalcet?
- take with meals
- watch for signs of hypocalcemia
what is the role of calcium?
- heart contractions
- clotting
- nerve functions
what drugs therapies are used for osteoporosis?
- calcium preparations
- vitamin D
- calcitonin
- bisphosphonates
- selective estrogen receptor modulators
what are examples of calcium preparations?
- calcium carbonate - TUMS
- calcium citrate - citrican
- tricalcium phosphate
what is Vitamin D?
fat-soluble vitamin used for chronic hypocalcemia is not well controlled with calcium supplements alone
what is Vitamin D used for?
- rickets and hypoparathyroidism
- recommended and for breastfed infants
what is calcitonin-salmon (Miacalcin) used for?
paget’s disease and postmenopausal osteoporosis
what are s/e of calcitonin-salmon (Miacalcin)?
itching, redness, and nasal irritation
what is the action of calcitonin-salmon (Miacalcin)?
- inhibits osteoclast activity which are the cells responsible for breaking down bones which then reduces calcium levels in the blood
- decreases the resorption of calcium in the kidneys
what is unique about calcitonin-salmon (Miacalcin)?
nasal spray - 1 spray per day and alternate nostrils
what do bisphosphates end in?
-dronate
what are bisphosphates used for?
prevent and treat and osteoporosis
what teaching is needed with bisphosphates?
- give in empty stomach with a full glass of water
- must remain upright for at least 30 minutes after administration
what is the action of bisphosphates?
inhibits bone reabsorption by osteoclasts which reduces the risk of fractures
what is an example of a selective estrogen receptor modulator?
raloxifene (Evista)
what is the action of a selective estrogen receptor modulator?
mimics the effect of estrogen on the bone
what is the use of a selective estrogen receptor modulator?
postmenopausal osteoporosis
what is the adverse effect of selective estrogen receptor modulators?
DVT, PE, fetal harm, and stroke of coronary events
