____a____(endocrine/exocrine) glands release hormones directly into the bloodstream, whereas ___b___ (endocrine/exocrine) glands release chemical substances through ducts, releasing outside the body.
a) endocrine (e.g. hypothalamus, pituitary, thyroid, adrenal, gonads, pancreas, parathyroid)
b) exocrine
this is the most common thyroid hormone
T4
what is the function of the thyroid gland in children
critical for normal growth and development
what is the function of the thyroid gland in adults
this hormone secreted by the thyroid is 4x more potent
T3
this hormone secreted by the thyroid is the major circulating hormone
T4
what do the TSH, FT3 & FT4 look like in hypothyroidism
TSH = increased
FT3 = low
FT4 = low
(Low levels of thyroid hormones, TSH increases due to -ve feedback)
what do the TSH, FT3 & FT4 look like in hyperthyroidism
TSH = decreased
FT3 = increased
FT4 = increased
(thyroid hormones increased, TSH decreased b/c of -ve feedback)
what do the TSH, FT3 & FT4 look like in subclinical hypothyroidism
TSH = increased
FT3 = normal
FT4 = normal
what do the TSH, FT3 & FT4 look like in subclinical hyperthyroidism
TSH = decreased
FT3 = normal
FT4 = normal
what is the best screening test for hyper/hypothyroidism?
TSH
give examples of high risk patients who should be screened for thyroid disease
what are some signs and symptoms of hypothyroidism
list examples of Primary Hypothyroidism
Levothyroxine (Synthroid, Eltroxin)
used for Tx of hypothyroidism
- synthetic T3
Short half life
Side effects: same as synthetic T4, may be worse since T3 is more potent
Liothyronine (Cytomel)
used for Tx of hypothyroidism
Animal protein derived (risk of allergic reaction)
Side effects: same as synthetic T3 & T4
Desiccated thyroid
when should the patient start to feel better after being started on levothyroxine for hypothyroidism
~ 2 weeks
how long after starting tx should TSH/FT4 be monitored in hypothyroidism
6-8 weeks -> FT4 more reliable indicator initially, but in the long run we want normal TSH
If a patient changes LT4 brands, or gains more than 10 pounds, when should they get their TSH checked
4-6 wks following these changes
what are the signs and symptoms of hyperthyroidism
ophthalmology:
- dry eyes
- blurry vision
- lid lag
this is a type of hyperthyroidism; most common; is an autoimmune disorder due to Thyroid Receptor Antibodies (TRAbs) which stimulate thyroid growth, hormone release
Grave’s Disease
this is a type of hyperthyroidism; autonomous thyroid nodules that secrete excess thyroid hormone (increased radioactive iodine uptake (RAIU))
tx = RAI or removal of thyroid gland
solitary toxic nodules & toxic Multi Nodular Goiter
this is a type of hyperthyroidism; inflammatory damage to the gland which increases release of hormones.
subacute = develops after a viral syndrome
painless = cause is unknown
tx = self-limiting, beta-blockers for HR, NSAIDs for pain control, steroids for severe cases
thyroiditis painless/subacute